Author Topic: My little SL350 rebuild thread  (Read 16326 times)

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Offline the-chauffeur

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My little SL350 rebuild thread
« on: July 24, 2010, 12:54:25 pm »
May 2010

A bike I've been after for oooohh, several months shows up on eBay.  It's an SL350 K0, and although it looks largely complete, it's no oil painting.  No big deal, I hear you mutter to yourself - they're a dime a dozen (well, nearly).  Yeah, I'd agree if I was based in the US, but nope, I'm in the UK . . . and from what I've learned since, I don't think there are more than a handful of these things over here.  In part that's why I've only been after one for such a short time - up 'til now, I didn't know they existed.  Did I end up paying over the odds for it?  Why yes, thank you.  I'm not sure what affected the sale price more - the rarity in this country or the relative completeness(?) - suffice it to say it wasn't cheap.

There's a bunch of other images, but here are the headlines:



Like I said, largely complete.  But not pretty.  Faded paint all over, dents and rust in the tank.  Messy frame.  Cracked tyres, faded controls, scruffy engine outers.  It's been over on the right side at some point, which bent (among other things) the bash plate.  The seller rather optimistically listed it as a runner, but buying at a distance meant I couldn't check that out.  Turns out it almost certainly wasn't true, but hey, thems the chances you take.

On the upside, although they were cracked and dinged, the sidecovers were there.  And ditto the exhausts, which also have their fair share of dings.  Before buying, I had no idea just how hard those things are to find.  I now know better.

So what to do - mild resto or all out showroom redo?  Well, it's a scrambler, so I'm steering away from bling overload.  It's starting out as a 9/10ths resto, but that may become more intense as I get more involved.  And no, cutting it up never crossed my mind.  Sorry to you bobber/chopper/modders out there, but the scarcity of this thing is taking me in other directions.

This first post comes a little late - I'm already well into the rework, but stupidly didn't take many photos.  What I'll probably do is a post on each element - front end, rear end, top end, bottom end, seat, engine and so on and update them as things move.  Should be easier to follow that way. 

And believe me, there's plenty to follow.

« Last Edit: May 29, 2011, 02:52:06 pm by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #1 on: July 24, 2010, 01:47:44 pm »

Teardown

After trying (vainly) to get it started, the unbundling began.  Nothing particularly surprising to report about the teardown - at least, nothing really horrible nesting under the outer clothes.  

The frame is straight, as are the forks.  The wheel rims are scruffy and consumables are irrecoverable - the chain's long gone.  Looking at the crap on the underside and in the fins of the engine, the bike was last used in a field and then stored in a barn.  Not very well.  The electrics are intact, but until I get to the stage of trying to get it going again, I'm not going to know whether the coils have any useful life left in them.

Minor discoveries - in addition to cracks and fading, one of the sidecovers was missing a lug.  The covers hid a couple of ugly looking air filters but no inner filter covers, which struck me as being very strange.  There were some other missing little bits and pieces like the battery cover and toolkit, together with one of the chainguard pieces and some of the little fastener clips and cable ties.  The more observant will also notice a brake pedal from a C90 - that'll have to go.  The clocks show 7k in miles covered under the bike's own power, which looks about right.  Unfortunately (as you'll see) it's time, rather than distance travelled, that hasn't been particularly kind . . .

So, bits were sorted into several piles, including one for frame and parts to go for powdercoating, another for painted parts, and so on.  Shortly after dismantling began local shops started running out of ziplock baggies.  And silicone spray.  And WD40.


Where we're at right now . . .

The frame and ancillaries are back from the powdercoaters.  I've tried to stick to the same colour scheme as the original and so the frame is silver, with a number of other bits having been done black.  Not a lot to say about the process itself, other than the frame looks a whole lot better than it did and cost around $250 in total.  A box of bits to give you an idea:


You can probably just make out that the bash plate is serviceable, but not brilliant, despite the powdercoat.  I really need an NOS one.  Another frame part that wasn't great was the tubular front mudguard stay, which was strangely deformed on one side - something I only noticed after it had come back from being powdercoated.   D'oh.  With no real hope whatsoever of finding a new replacement, I put in the part # to CMS/David Silvers and to my amazement there are still a couple of NOS ones on store shelves out there.  Good job 'cos the tubular frame would be a nightmare to reshape.  Another surprise was that I managed to fit the lower suspension bushes into the swingarm using little more than a freezer, grease, threaded rod, oversize washers and nuts.  I also modified the swingarm bushes using Hondaman's guide in his 750 book (buy it - it's great - and lots of the frame advice applies across the Honda range).

Chromework.  Hmmm.  Originally I was going to leave much of the chrome because although it's a bit grotty in places, it's still serviceable.  However, a few hurdles have since appeared on the timeline horizon, meaning that I'm going to be doing lots of hurry-up-and-waiting.  So a bunch of stuff is going away to be replated -

Front rim / rear rim / spokes and nipples / handlebars / fork tube covers / headlight ears / tach and speedo mounts / instrument bridge / taillight mount / horn cover / exhaust roses / carb tops / rear brake pedal

The paint is also done.  More on that later.  Ditto the engine in bits.

Tyres pretty much fell off the rims, but the innertubes seem perfectly fine.  The problem there is finding matching front and rears, given the unusual wheel size.  Looks like my only real option on that front is Dunlop K70's . . .
« Last Edit: October 23, 2010, 09:47:59 am by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #2 on: July 24, 2010, 02:15:34 pm »

Suspenders

There's good news and less-good news.  

The good news is that the rear shocks are very clean.  There's minimal surface rust on them and after pulling them apart and cleaning off 40-years' worth of dirt and grime, they look - and seem to work - fine.  I'll maybe disassemble them again and put the coils into a bowl of coke/rust remover to lift off the last remaining rust traces I couldn't reach with a toothbrush, but other than that, they're about as good as they need to be.

The not so good news was the fork stanchions.  Wouldn't you believe it, 98% of the chrome was shiny and solid . . . but that remaining 2% was a rust bubble right on the point where the left stanchion crossed the oil seal in the leg lower.  It didn't need any encouragement in flaking off and showing just why the seal was shot.  Stripped the forks down and noted the internals weren't great - and the 'oil' left inside them needed removing with a spade.  I also noticed the fork caps were really scruffy and needed replacing or rechroming.  

Sent the stanchions off for hard rechroming and regrinding, and asked very politely if they'd also do the caps.  The response was that they probably couldn't, 'cos the caps needed decorative (as opposed to hard) chroming, but send them along anyway and they'd see what they could do.  Three weeks later, they were back and looking great.  Total overhaul cost to me was about $250.  No photos 'cos one stanchion's much the same as another.  But as for the caps . . .


Yay!  

While they were apart, I polished the lowers.  Not to a mirror finish, but shiny enough to not look out of place.  Rebuilt the forks with new upper and lower bushes, but had to buy 2 sets of oil seals - the first set turned out to be for, well, not the bike I was told they were for.  And that was another lesson - Honda's fork seals aren't cheap.

Completed forks now sit in a corner of the workshed.  Might be a while before they get mounted and properly tested.
« Last Edit: October 23, 2010, 09:49:38 am by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #3 on: July 24, 2010, 02:33:19 pm »
Seat

Another piece that observant folks will notice needed some serious attention.  Cover was discoloured in a couple of places and torn in others, which in turn had played havoc with the foam.  The seat pan was really grotty - surface rust again.  But at least most of the hardware was there in varying states of repair.

So the search for fixin' bits was on.  eBay again turned up the best options - replacement precut foam ($60) and to make sure I got the closest match in covers, I opted for one of the reasonably expensive far eastern copies ($80).  As with the frame, the pan went off for powdercoating and came back looking sharp.  The foam was a good fit; the cover was tight but after some huffing and puffing (and help from a hairdryer) it all went together.  I've since read an article on recovering seats that recommends putting a very thin plastic layer between the cover and the foam to aid placement . . . if I'd thought of that it would have saved me a couple of hours fighting.

During the stripdown, I managed to extract the chrome buttons from the sides without too much grief.  The cover kit came with replacements, but I thought I'd reuse the originals for that slightly-faded-glory touch.

And now it looks a little bit like this:



The lock catch and rubber pieces have all either been cleaned up or replaced.  The last piece was the seat stay, but they're virtually impossible to find for the K0, so I ended up using one intended for a CL350 instead.  Part# 77216-286-000 turned out to be an almost perfect replacement for the SL item. The angle of the bend was slightly too obtuse, but was made more acute with a little brute force.  I also stuck a little rubber cap on the long end piece to stop it digging holes in my nice frame powdercoat when I use it to hold the seat open.
« Last Edit: October 23, 2010, 09:50:52 am by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #4 on: July 24, 2010, 03:34:08 pm »

Exhaust

I know, I know.  Part one of the 'holy grail' of the K0's.

Once I'd realised just how rare they were, I gingerly removed the pipes and looked over them to see what I was faced with.  Fortunately for me, both sets of headers and mufflers are amazingly tidy and more importantly, the outers are rot free.  The orange/rust coloured bits in the main photos seems to be the material under the paint - making me think that the muffler outers were stainless (I'm not entirely sure that's right, but it's the same colour as stainless headers go after a while).  The outer protector plates are also intact, although one has seen more action than the other.  

The same can't be said of the muffler inners; one of them is pretty much complete inside, but only around 1/2 of the other remains - the rest of it sort of fell out in dust and small pieces.  I can't see the incomplete inners being a great problem other than from a noise perspective - and if they're too loud, I guess I can get some loose packing material in there.  

Restoration consisted of beadblasting the outers and trying as best I could to wiggle out some of the small dings in the mufflers.  The header-to-muffler joint collars proved to be a problem because bi-metallic corrosion had effectively welded the tightening bolts in place . . . so much so that I had to cut the head off one during the teardown (otherwise I'd've buggered something else up).  After no luck trying to drill out the residual bits, I took the collars to an engineering shop and they cleaned 'em right up.

And then everything that needed it got several coats of VHT flat black and a couple of new rubber bits.


(The other one is in the bubblewrap underneath).

I guess I could've gone gloss, but just about every K0 picture I've found shows flat black exhausts.  If you look very carefully, you can still see some minor dings - they're not sharp or blunt; more gentle bumps, and not so intrusive that they warrant serious invasive work.  The flat black hides them fairly well.  Maybe they'll go gloss one day when everything else is done.  Meantime, I think I've tracked down some gaskets for the header-to-muffler join which is no mean feat, given they were never sold as individual parts . . .

« Last Edit: October 23, 2010, 09:53:46 am by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #5 on: July 24, 2010, 04:15:37 pm »

Paint

Did I say how scruffy it started out?

Turns out a good paintjob on something like this isn't cheap.  First, there's the sheer number of painted surfaces - 6 separate parts.  Second, there were dents, pits, minor rust and other imperfections in all of the bits with the exception of the headlight bowl.  The tank had bumps and scratches on both sides and then there are the  white flashes that would need recreating.  The side panels were another story - they're made of the thinnest plastic I've ever seen and are fragile as hell.  That said, one had a dent in it, which was something of a surprise . . . very weird . . . I didn't think plastic like that dented.  As for the other, it had a 2in crack in it, and was missing the lower lug.  

So in addition to pulling/reshaping the tank and mudguard dents and dings, there was a fair amount of plastic welding to be done.  And then there's the cost of the paint itself.  Being a candy, it needs several different processes - one containing a UV ingredient which I'm told is hideously expensive - and the complexity of the tank striping is no mean feat to re-apply.  The prep work alone must've taken hours (although I had the mudguards blasted clean when I got the frame done).  As for colour match, there was some original unfaded paint on the underside of the tank which I told the sprayer to use as a guide.

Five weeks later, and here's a small sample of what came back:


Pretty sharp, huh?  Bad light stopped play today, so I'll post more another time, but it looks really good.  If I'm being hyper-critical, it's around a 98-99% job - over the last few weeks I've found some tiny imperfections in a few places, but they're soooo small, most observers will be real hard pressed to find them.  Total cost was about a grand (yeah, eye-watering but pretty much worth it).

Being an early K0, the 'Honda' logo on the tank was a transfer, and not something Honda have ever sold (I've since found that CBdecals.com make repro white stripes with the logos, but that's another story).  Frankly, the Honda part of the originals wasn't something I could replicate without throwing quite a lot more cash at it.  But it turns out that shortly after mine rolled off the assembly line, Honda changed the printed logos to metal tank badges - a far more sensible idea if you ask me.  So to save a whole lot of screwing around, I've picked up a NOS pair of badges to be fitted once everything else is complete.  Not a route I'd've taken if I was an absolute purist . . . so it's a good job I'm not.

That wasn't the end of the tank story.  When it arrived, the tank had the most eye-wateringly foul smelling liquid inside it - something akin to a mix of thirty-year old fuel, 2-stroke oil and acetone.  It was so unpleasant it had eaten through one of the fuel cock filters, and the fuel tap itself was solid with an evil combination of chemicals.  So I flushed the tank before I sent it away for painting, but didn't look too closely inside.  It was only when it came back all sparkly on the outside that I noticed the coating of surface rust and pitting on the inside.  Crap.  Literally.  

After doing some research, I came up with two or three possible remedies: electrolysis, Metal Rescue-type rust remover or tank liner.  I've seen some really poor tank liner results before, so I thought I'd only go that way if I absolutely had to.  Electrolysis seemed like a bloody nuisance, so I took the path of least resistance and went with the liquid rust solution first - at least I wouldn't lose anything/screw it up if that didn't work.  Having part-filled the tank with distilled water and dumped in a couple of metre-long pieces of small link chain, I shook it about a bit in an attempt to take out any loose debris.  It's the same principle as using sand or lead weights, but chains are much easier to extract (just use a magnet).  I then filled the tank with the liquid remover and left it for a week.  And what a difference seven days make.  Again, sorry for the lack of comparative before shot, but:


The inside is back to bare metal with no sign of rust.  Way cool.  The last step was to flush it out, again with distilled water, and then with a petrol/2-stroke oil mix to protect it for the next month or so before it sees any real action.

And order a new fuel tap.
« Last Edit: October 23, 2010, 10:03:17 am by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #6 on: July 24, 2010, 04:33:59 pm »

Carbs

The main reason why I very much doubt the seller was able to get the bike running.  They were in a horrible state - inside and out.

Much like the engine cases, the outers were covered in dried mud and dust.  Taking them apart revealed dry float bowls and jets covered in a sticky residue.  Whatever fluid had been stored in the tank had made its way into the carb bodies at some point, but that was about as far as it had gone.  Disgusting.  All of the o-rings were hardened to the point of cracking.

I got busy with cleaning the outers and ordered a couple of o-ring repair kits.  Two encouraging signs - the floats were hole-free and the diaphragms were still flexible.  The jets were resigned to a jewellery ultrasonic cleaner and the diaphragms soaked in silicone solution (to keep them soft) until the o-ring kits appeared.  Only useage will tell how well the clean-up worked.  Here's your obligatory before-and-after shot of the outers:


There are a couple of areas where the black paint has peeled, so they'll need attention, but they're minor.  Since I've got a pile of stuff to be rechromed, I've decided to send out the caps as well.  The stock chrome is still pretty tidy, but the cost of getting them done properly is gonna be negligible when they're bunged in with everything else.
« Last Edit: July 25, 2010, 05:32:51 am by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #7 on: July 24, 2010, 05:02:48 pm »

Electrical

Something I've found is that these bikes weren't big on electrics - with no indicators, there's only half a dozen or so circuits to worry about.  While it was in one piece, I tested the lights and horn, which were fine.  The starter worked, but only with a direct feed from the battery, and because I couldn't get it to run, I wasn't able to do much in the way of testing the charging circuit.  Now it's in bits, I've resigned myself to tidying up the already neat wiring loom - which pretty much just needs some better quality heatshrink and a couple of new bullet connectors soldering on - and overhauling the switchgear.

As I said, faded.  The top pictures show the state they were in when the bike arrived, and it was soon after pulling off the right-hand switchgear that I found the reason the starter wouldn't - the starter wire in the switch housing had snapped.  After seeing the price of NOS RHS switchgears (the prices reflect their similarity to the Sandcast CB750 bits they're virtually identical to), I thought I'd have a go at refurbing the ones I had.  Feeling brave, I extracted the switchgear internals - with just the horn button, the left is a whole lot easier than the right - and sent the outers off with the frame and seat pan for blasting and powdercoating and while they were away, used some spray plastic paint on the very faded black killswitch knob.

Reassembled, the right hand side looks a bit like this:


It needs a little red paint on some of the lettering, but that's about all it wants to look new again.  I've checked out the connections and they all - including the starter button - work fine.  Before they go back on I'll put some waterproof grease on the internals to keep out moisture.  

More news on the other electrics as the rebuild goes on.
« Last Edit: July 25, 2010, 05:36:53 am by the-chauffeur »

Offline hoodellyhoo

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #8 on: July 24, 2010, 07:25:22 pm »
Very interesting thread so far. Looking forward to more updates.
1972 CB350F (Back from the Dead!)- http://forums.sohc4.net/index.php?topic=20822.0
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Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #9 on: July 25, 2010, 05:16:53 am »

Engine – general / bottom end

Once out of the frame, the engine needed much elbow grease – a whole lot of cleaning.  It’s amazing how stubborn field mud becomes over time.  Might not look like it from the early pictures, but there was mud covering the lower and side cases and in and around the fins.  No amount of scrubbing, degreasing and soaking would shift it, and so I look for a more radical approach.

First off, the easily accessible side and top covers.  After trying unsuccessfully to tart them up, I decided to take them to Dale the polish with strict instructions not to go mirror-finish beserk.  Could do the ali polishing myself, but decided it was too much of a messy job and Dale’s set up for that sort of thing.  Anyways, he’s buggered off on holiday for the next few weeks, so there’s some wait time I wasn’t quite prepared for.

In the meantime, I disassembled the remaining engine parts, extracted all of the internals and took the big top and bottom end bits to Dave the vapours.  A couple of weeks later and he’s blasted the outers with beads and water and they’ve come up looking very smart.  Although Dave had washed the cases before I took them away, I ran taps through the various bolt holes and extracted about a teaspoon-full of dust, dirt and tiny beads.  The clean cases then went into the dishwasher, followed by a de-ionised water bath and then a rinse with white spirit.

I’ve decided not to paint the main pieces for several reasons.  Firstly, I’ve tried to paint several engines before and not once had satisfying results despite trying a number of different methods, heat treatment and allsorts.  Second, the cases look pretty good as they are, and Dave reckons that with periodic applications of ACF50, they’ll stay that way.  And lastly, I come back to the fact that the bike is a scrambler and so wouldn’t look right being overly spiffed up.

Right now, we’re at the point where the lower cases and internals are reassembled and buttoned up – and sitting on the shelf.  


Fortunately, the bottom end internals showed no signs of damage or any real wear – well, with only 7k on the clock, I was kinda hoping that would be the case.  The oil (if that’s what you can call it) that was floating around inside before I dismantled the bike seems to have protected the moving parts from ageing.  So with the exception of a spring clip on the kickstart mechanism that snapped when I tried to remove it and a couple of locating dowels, the only bits I needed to replace were oil seals.

Really wish I could say the same of the cylinders and top end . . .

Quick update on the engine

Dale's back from holidays and he's been busy with his polishing toys.  Just picked up these:


I'm hoping they'll stay looking this good.  I've got myself some rim wax (intended for chrome wheels) which I've polished into them in the hope it'll act as a protectant.
« Last Edit: October 23, 2010, 10:13:12 am by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #10 on: July 26, 2010, 01:25:41 pm »

Handlebars

I think I mentioned my suspicion the bike had been down on its right hand side at some point.  Well, I wasn't wrong.  Of all things, the handlebars are wonky.

I have to say it took some squinting at funny angles and measuring up against other bars to be sure, but they're definitely off centre.  Spotting the shift is made more difficult because of the trapezoid shape the crossbar forms with the main pipe.  Anyway, once I was sure they were out, I realised there was no point getting them chromed - I need a straight set first.  The relative scarcity of this bike doesn't help - yet again, no spares to speak of in the usual places, so it looks like I gotta work with what I got.

The bars have gone off to a frame straightening specialist down the road.  Initially he was dubious 'cos he said chromed bars are always hard to work with for fear of destroying the chrome with heat.  Once I'd explained I was gonna get the rechromed anyway, everyone was happy.  I told him to get on and do whatever to get them either back to, or very close to, original shape.  That'll take a few days, and then we're off to find a chromer.

Did I mention the top end troubles?  Thought so . . . I'm getting round to that.

Quick update on the handlebars

Picked them up from the straighteners, but sadly, they're not much better than before.  The ends are the same height, and have the same rearward sweep, but there's still a torsional twist in there.  For now, I reckon I'm going to have to go with an aftermarket set.  I know I'm about the only one over here who'll know the difference, but even at this early stage, I guess it's going to be one of those little detail things that'll bug me until I (eventually) find a proper set.
« Last Edit: October 23, 2010, 10:15:16 am by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #11 on: July 28, 2010, 09:11:41 am »

Top end

This was the bit where it dawned on me the rebuild was going to be more costly than I'd originally thought.

Time - and standing in a field - is the enemy of motorcycles, and this one was no different.  Taking the top end off revealed that not everything in the engine had remained covered in a film of oil.  Whilst nothing was broken, lifting the lid revealed a camshaft that had pitting on three of the four lobes.  Not exactly potholes, but marks deep enough that if left unattended would ruin the rocker faces.  And yes, the rocker faces were also pitted in areas corresponding with those on the cam lobes.  It looks like very small amounts of condensation had gotten in when the bike was last used and stayed put.  Over time, it ate away the unprotected surfaces.  

Visually, the other cam components like the sprocket, spring retainers and valve guides look fine, as does the chain - although I've not been able to find a service limit guide for the cam chain, so I have no idea whether it's still good or not.  And then there's the springs and camchain guide wheels.  The guide wheels were scruffy, but that's no great problem - they're still available.  However, after waving the verniers at the springs, I've discovered two outers and two inners are squished beyond their service limits.  Probably victims of continuous compression (and no movement) over thirty plus years.  Nope - they're no longer available new, unless of course you want to spend $$$ on remanufactured titanium racing kits . . . thanks, but no.

Then there are the valve faces and seats.  Quite why a bike with only 7k miles on it would have worn valve seats, I dunno.  But again, the wear was in the form of pitting, so I s'pose it's possible my hypothesis on the camshaft lobe/rocker face damage could also be responsible for the valve seats.  In any event, the wear was bad enough that lapping alone was not going to bring the seats back to usable condition.

And last - but by no means least - we move on to the cylinders.  Like the head, from the outside the cylinders look fine, but one of the inners tells a different story.  Despite looking pretty clean (all things considered), one barrel had a scratch from the top to bottom of the piston ring run area.  It's weird - one scratch, looking like it occurred on one stroke as opposed to repeated piston movements.  I'm wondering if it happened when the folks I bought the bike off got it, ahem, running(!?!).  Annoyingly it was just deep enough to not want to come out after honing, and so the only real option is to go for a rebore and go to first oversize pistons.

Not the most inspiring of finds.  So where are we now?

First order of the day was to get the camshaft/rockers fixed up.  Much to my amazement, NOS camshafts for my bike (very early production model) are still available, but not cheap.  So for half the price of a new 'shaft, I got the mine repaired, and the rockers retipped.  Phil the cams took about one thou of an inch off the cam lobes and reprofiled them to the right shape, and to keep the performance as close to stock as possible, he built up the rocker faces by the corresponding amount.  And here's what they look like:


Someone on another forum has pointed out that the journals look pretty crappy in the above picture - and he was right, they do.  Fortunately a quick buff on the polishing wheel cleaned them right up, so what you see in the picture turned out to be crud.  And now they're almost as shiny as the lobes.

The head has gone off to Brian the engineer for a valve job.  He's got the valves and the heads and by the sound of things will recut the seats and properly lap in the valves.  In the meantime, I found that Sirius Inc supply 1st oversize pistons and rings and when mine arrived, the cylinders and new pistons went off to Martin the rebore.  Not sure how long that'll take - he's busy right now.  I also stumbled across a used set of valve springs on fleabay; I'm just hoping I can make a good set out of all of the various springs I'll have when the bits arrive.

More pictures when the various bits come back . . .

Quick update on the cylinders

Martin the rebore has done his thing and I now have a set of decent bores.  I've been round the cylinder outer casing with a dremel and a fine bit making sure all of the cooling airways are clean and wide open (another little something I learned from Hondaman's book on the 750's).  All I need now is the valve job finished and we're good to go on the top end rebuild . . .
« Last Edit: October 23, 2010, 10:24:03 am by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #12 on: August 14, 2010, 03:11:49 pm »

Wheels

To date, next to nothing associated with this build has been easy.  Just about everything that could go wrong, or be a bloody nightmare to put right, has.  So why I thought the wheels would be any different is anybody's guess.

In fairness(?) to the bike, the front rim was in pretty good shape.  Unfortunately, after wire brushing the rear rim inner (the bit the tape sits in), the rim started sounding like it was full of sand . . . well, rust bits.  All of the spokes looked pretty crappy, even after soaking and polishing.  Yes, it would have been cheap to use a bit more elbow grease on the spokes, but there was no way - beyond rechroming - the rear rim was ever going to look as good as (I hope) the rest of the bike will.  And if you rechrome one . . .

 . . . moving on, I'd been keeping my eye out for sources of the same size rims to replace mine.  I wanted to keep them chrome to retain as much originality as possible, and although I know the sizes are problematic with tyre options, I thought I'd stick with the same dimensions - 1.85 x 19 front and 2.15 x 18 rear.  By chance, one of my eBay trawls turned up a far eastern seller advertising a pair of K0 rims, and another selling spokes for the same.  Bonus, I thought, particularly because even with delivery they'd cost 2/3rds what they would here.  So I put my orders in, at which point things start to come unstuck.

A day or so after placing the order for the rims, I got an e-mail from the seller asking me to confirm I was happy for him to send me a 1.65 x 19 front and a 2.00 x 18 rear.  Er, no - I don't recall those figures being anywhere near correct.  Yes, said the seller, but these are the sizes we fit over where we are because they are lighter than the original sizes.  Ah, I see - you're not selling straight replacement K0 rims; you're selling rims that can fit a K0.  Why the f*~# didn't you say that in the ad?  After a bunch of to-ing and fro-ing (all very cordial, I might add), the seller said he could do a correct front and an ali rear in the size I wanted - again, no good to me.  Move on a week, and we decide to terminate the deal - again, a pleasant enough transaction (I really can't be bothered to get upset about this sort of thing), but a complete a waste of time.  I've ended up ordering chrome rims (with all of the right drilling) from over here - something I now realise I should've done in the first place.

And then the spokes arrived.  Chrome they are, but butted (like the originals) they ain't.  Somewhat more worrying, the fronts seem to be a few mm longer than the originals and the nipples are a completely different shape.  Trouble is, until I have the rims I'm going to lace them into, I've got no way of knowing whether they'll fit.  Oh well, I guess I can always grind them down a bit if needs be.  Could be worse - at least they're not too short . . .

Quick update on the wheels

I was right about the spokes being too long, but wrong in thinking it was just the front end.  Both ends were about 5mm too much.  A tip for anyone else out there considering ordering from eBay - unless you want to spend a few hours trying to figure out how best to cut down the spoke ends, don't.  Buy from a reputable supplier and make sure they get the sizing correct.  Grinding down 72 spoke ends is no fun.
« Last Edit: October 23, 2010, 10:27:16 am by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #13 on: September 05, 2010, 07:45:53 am »

Handlebars (pt 2)

The aftermarket set I've ended up with are close, but there are some obvious differences.  The original have a strengthening section on the lower edge and the crossbar is higher and at a sharper angle.  More problematic was that they weren't drilled - and if you've never tried drilling chrome bars without a fully kitted out workshop, you won't know what a joy(!) that job is.  Grinding wheels and Dremels make life easier, but it's not a job I'd recommend doing unless you really have to.

So they're drilled and assembled.  The cable covers (for the electrics) are pretty scruffy, so I'm on the lookout for heatshrink tape or similar. Other than that, I just need to fill in the lettering on the right-hand switchgear with red paint.  Oh, and swap those scruffy brake/cable ends for tidy ones (hopefully without paying through the nose for the Honda bits, which are ludicrously expensive).






Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #14 on: September 05, 2010, 08:10:14 am »

Engine - Top End (pt 2)

I finally figured out what professional restorers already know about why some restoration jobs take so damn long.  Pulling things apart and putting them back together doesn't take that much time.  Neither does putting in your orders and getting bits delivered.  Nope, what really holds up progress is the workload of the folks you rely on for rebores, crank regrinds and other specialist work.  Take a rebore - the setting up, drilling and honing itself takes at most a couple of hours.  However, if, like me, you're dealing with small engineering shops, it often takes them two to four weeks to get round to even looking your stuff.  Add in postal/delivery times - and some antiquated payment systems - and it's easy to see how these things can drag on for months.

Newfound wisdom section over, let's move on. The head was treated to recut valve seats and a combination of springs from a couple of different machines to get a complete set that were in tolerance.



The cylinders came back, overbored by 0.25mm and nicely honed clean.  New pistons and rings are also shiny lookin'.  Various cam train consumables were replaced, too.


And with newly vapour blasted cases, it was time to start the rebuild . . .
« Last Edit: October 23, 2010, 10:30:13 am by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #15 on: September 05, 2010, 08:23:00 am »
Engine rebuild

Not a lot to say here, really. 

Once I'd cleaned out all of the thread holes with taps covered in grease, the lower half of the engine was very straightforward to reassemble with new seals - probably because I hadn't split the crank or various gear assemblies into their component parts.  With only 7k on the clock and no obvious signs of damage, there didn't seem to be a whole lot of point in going beserk.

As for the top end, I had a bit of a struggle getting the camchain over the sprocket because of the lack of wiggle room. Once I'd figured out that the sprocket needed to be put in the chain loop just above the cylinders and then passed up through the various gaskets and two other head sections, it made a lot more sense.

And here it is:


The wheels are away for new tyres right now.  Once they're back, reassembly proper can commence . . . he says . . .

Update

It took me a while to realise that I'd made a silly mistake during reassembly that resulted in a leak around the head gasket.  As previous images attest, I'd removed the cylinder studs prior to the cases being blasted, and when I put them back, I tightened them to manual spec thinking that would be the end of it.  Nope; not only do they need to be torqued properly but the tops need to end up at the right height from the face of the upper engine case so that when everything is assembled, the top nuts can be properly torqued down without bottoming out and not putting the top end under the correct tension. 

I now know how obvious this sounds, but I managed to make the same mistake on both of my SLs (see later posts).  Yes, it took me a while to figure out and yes, if you've pulled the studs you need to assemble everything dry - gaskets and all - to check that all the studs end at the right heights before finalising everything.  If you do the dry run without the pistons or cam train being installed, it'll take you no more than five or ten minutes, and that simple check may save you the head-banging it gave me for longer than I care to mention.  Still, I got there in the end . . .
« Last Edit: April 03, 2019, 12:50:09 pm by the-chauffeur »

Offline gregk

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #16 on: September 05, 2010, 08:35:20 am »
chauffeur

I may have a NOS tach for your restoration.  The tag claims it will fit an XL 350 but it appears that this tach was also used on the CL 350. 
Got this tach in a box of other parts, and will sell cheap.

greg
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Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #17 on: September 06, 2010, 05:08:05 am »
 
Clocks

Thanks for the offer Greg - very kind.  As it happens, I've already got the clocks pretty much sorted.  This is how they started out life:


The speedo, whilst scruffy on the surface, was pretty darn clean underneath.  The perspex front was clean and relatively unscathed, the face wasn't particularly faded - although the pointer's a little off colour - but it had clearly never been apart.  It took some elbow grease and toothpaste to clean up the front, and it's now ready to go back into service - assuming it works (something I've not yet been able to test).  

Sadly the same couldn't be said of the tach, which hadn't survived quite so well.  If you look carefully at the picture above, you can see clouding on the inside of the perspex face, which was also scratched.  Taking the clock out of the base, the insides pretty much came away from the outer case . . . which went some way to explaining the condensation traces and clouding on the clock face and inside of the perspex.  Someone's been at it before.  So plenty of eBay trawling later, I've now got this:


Comparing the new with the old, I think I've got the right replacement - certainly the redline on the new on matches the one that came with the bike.  

Back to your tach, Greg - it looks to me like it might be compatible with the K1 or K2 SL350 models, but not the K0.  Another giveaway is whether it has a narrow chrome band round the sides.  The earlier models don't - they're plastic sided and sealed.  But again, thanks for the offer.
« Last Edit: September 06, 2010, 01:33:10 pm by the-chauffeur »

Offline putnaja1

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #18 on: September 06, 2010, 06:20:00 am »
Wow! What a great looking bike you've got there!  Reminds me of a very nice XL a riding buddy of mine had in the early 80's- and it always looked so nice I could never understand wanting to take that nice a machine riding in the dirt!  Darn, I've been trying to hold off on my desire to find an old CL175 to restore until I finish with my BSA restoration- but seeing this SL makes it tough!

You're doing great quality work there!!  Excellent work!
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Offline fastbroshi

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #19 on: September 06, 2010, 01:42:51 pm »
  That bike's going to be a, er, KO when you get done.  Don't think I've ever seen one before.  Lots of CL's for sure. 
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Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #20 on: September 12, 2010, 04:05:33 pm »

Thanks guys.  I'm hoping it'll look pretty spiffed up.  Actually, I sorta know how it's gonna look . . .

Re-assembly pt.1

The wheels came back with tyres on yesterday.  Dunlop K70's - about the only matching tyres that fit the K0 rims.  Not sure why, but to get the beads to seat, my shop buddy's inflated the innertubes to 80+ psi.  They held OK, and the tyres are now at the right pressures.  And they look sharp (in a rubbery kinda way), too.

So with the wheels sorted, the bike has a base.  The basic (big) parts of the reassembly started well.  Wheels on, engine in, carbs on, and generally it all seemed to be pretty straightforward for a good few hours.  That was until I gave the kickstart a bit of a wiggle to see how easily (or otherwise) the engine would spin.  And it did - very briefly - and then ping . . . the circlip on the very end of the kickstart shaft on the inside of the engine case - the same one that I had replaced earlier - gave out.  I dunno how or why - it just did.  Yup - that's the engine out again.

Three hours later, the kickstarter assembly was fixed and the engine was on its way back in.  Then, annoyingly, it clipped the frame.  Not massively, but enough to put a few marks on the powdercoat.  Not sure how I'll cover them right now; I was more concerned with getting everything back together.  Back together it pretty much went, with me remembering different bits that needed to be added, moved, shifted, taken off and turned round jigsaw puzzle-style.

By the time I got finished this evening, I was nearly at the point of putting the exhausts back on.  And it was only then I discovered why the brake pedal felt so loose.  Of all the bits to go missing, I seem to have lost the brake pedal spring.  Can't find it anywhere.  Nowhere.  Gone.  It's not like it's a small bit, either - it's a big ol' coil.  Quite what's happened to it, I don't know - that said, the brake light spring was almost stretched to breaking, so I'm beginning to wonder if it had a brake pedal spring when I got it.  Either way, I'm on the hunt for a replacement . . . anyone got an SL350 K0 rear brake pedal spring they could be tempted to part with?

The only other news right now is that there are a couple of electrical gremlins that I need to trace - one is to do with the starter button, which works when the lights are off, but doesn't when the lights are on.  That - and the horn - aside, pretty much everything does what it should, and we've got sparks from the plugs.  So that's good.

Pictures to follow.  Now time for sleep and then brake spring hunting . . .

Quick update on the frame

I mentioned the few little dings in the powdercoat, right?  Well, I looked up a few fixes on t'internet and the one that came up must often (and seemed the least painful/risky) was make a paste by mixing a small amount of powder with thinners.  Then, using a selection of fine art brushes, fill the dings with the paste - hey, the powder in powdercoat is basically just paint, right?  

For me, this solution worked really well - the powder on the bike isn't a uniform colour and has several grey/ali tones in it, with some shiny bits to give it sparkle.  Consequently, the repairs blended very well; fortunately, the dings were small and in unobtrusive areas, so you can't tell what's original and what's a fix.  I'm not sure how well this method would work with a uniform colour - like a black gloss - but it's certainly worth a go.
« Last Edit: October 23, 2010, 10:50:49 am by the-chauffeur »

Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #21 on: September 13, 2010, 10:53:40 am »

So, we've gone from this . . .


 . . . to this (with apologies for the poor light and uninspiring backdrop) . . .


As you can see, it's still missing a few bits.  You'll all be pleased to hear I've found a rear brake spring - it'll just take a week or so to get here.  

Meantime:

- the exhausts are staying off until the rear brake pedal spring is fixed on - the heatproof paint on them is too fragile right now ('cos they've not been heat treated).  Don't ask.  I find it best not to.

- the electrical gremlin turned out to be a grounding issue . . . looks like the powdercoat on the switchgears is just too good.  

- the tank needs finishing - fuel cap, side badges, fuel lines and inline filters need fitting

- some of the control cables need replacing - they're on order - and minor tidying like the horn cover going back on

- chain needs fitting, as does the skid plate once it's back from being powdercoated the same colour as the frame

Once that lot's done, it should just be a case of filling it with fuel and oil (praying it's oil tight) and, erm, pressing play . . .




Yeah, right.
« Last Edit: September 13, 2010, 10:59:32 am by the-chauffeur »

Offline fastbroshi

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #22 on: September 13, 2010, 11:40:31 am »
You're almost there, and you work really fast as far as the final assembly went, bravo.  Pretty cool that the first SL I've seen was done this well.
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Offline the-chauffeur

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #23 on: October 18, 2010, 08:47:53 am »

A very small (but not insignificant) update.

Finally got all of the little jobs in the above post finished.  None were particularly tricky, just time consuming - and/or involved waiting for overseas deliveries.  So anyhoo, I got it to the point where it was ready to run, but try as I might, I couldn't get it to fire.  No amount of prodding and twiddling with levers and dials was gonna get me started and so in exasperation, I wheeled it off to my local Honda shop.  There's a couple of guys there who cut their teeth on the old CB's and so after some poking around, they worked out that I'd put the cam lobe on the spark advancer 180 deg out - in other words, it was sparking at BDC instead of TDC.  If that wasn't dumb enough on my part, I'm sure that's not the first time I've gotten myself into that situation.  D'oh.  They then set up the timing, checked the clearances and balanced the carbs . . .

 . . . and so here it is in all it's, ahem, glory.  Again, apologies for the background - until the bike is registered, I can't take it out on the road.




Yes, it runs - and very sweetly, too.  It's got a kind of easy, lazy idle to it, which seems to suit the bike's character perfectly.  Although the registration thing is still to come, I did get to ride it home from the test centre, and boy is it good fun.  Pulls hard, and trots along very easily.  Sounds fantastic, too - I think I mentioned before that the exhausts were in better shape externally than internally so they've got a bit of a straight-through sort of sound to them, but even then, it's not exactly an offensive noise.

Like any project, I doubt it's ever going to be completely finished.  There's still plenty of room for improvement, and shiny though it looks, I never did get round to having the chrome redone.  I may go mad with chroming at some point, but I say may 'cos that decision will very much be down to costs.  Dave Silvers still has things like the fork covers and headlight ears as NOS, which may well end up cheaper than a rechrome job - and I keep an eye on his ever-changing stock for odd bits.  I guess we'll just have to wait and see.  Incidentally, I'm still on the lookout for a set of 'bars but again, finding a good, straight, unmarked set is going to be a pig of a job over here, so I'm in no hurry.

The exhausts will probably need to come off for another coat of paint, too - they're showing signs of a few drops of fuel here and there.  And those tiny marks on the red only I seem to notice could be made invisible.  The carbs could also do with being repainted (black), but until I can find a finish I know will stand up to fuel spills they can stay looking the way they do now.

Finally, of all of the other extras I've got in mind, I guess the one thing I will almost certainly add is a Hondaman transistorised ignition.  I cannot be doing with messing about with points any more.  They're set now; I'd like them to stay that way.

Now all I've got to do is finish the 450 twin, and rebuild the 750 K2 engine from the ground up . . .
« Last Edit: October 23, 2010, 10:54:26 am by the-chauffeur »

Offline hoodellyhoo

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Re: This SL350 K0 rebuild is gonna be a cake walk . . . isn't it?
« Reply #24 on: October 18, 2010, 05:03:17 pm »
Great job!!!  That bike looks fantastic!
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