Author Topic: Keep telling yourself - a restored 750 K2 is an investment (Read 38569 times)

the-chauffeur · « **Reply #100 on:** December 09, 2008, 03:48:15 PM »

Man, it's been a long time since I was here last. I had to go back seven pages to find this thread. Just shows how industrious the folks who use this site are - by comparison, the UK board has hardly moved . . .

And so to business. After what seems like an eternity, the engine is home again. The boys at the garage came up trumps and have done more work on it than anyone thought was going to be necessary. Not only have they replaced the bearing journals (hooray - the crank moves nice and freely), but they did some checking and measuring while they were in there. Almost everything is within tolerance, with the exception of one of gear selector forks, but they tell me it's not significant and won't be noticeable - good job too, 'cos they're now obsolete. Even better, they found and repaired some stripped threads, which came as something of a surprise. In putting it all back together, they stuck a new top-end gasket set on and torqued everything up/down.

The downsides? Well, there are two - scuffed paintwork on the casings, and the cost. As far as the paint is concerned, it was only stuff I'd sprayed on myself, and since the engine hasn't been run yet, it hadn't cured. I've since bought some brush-on VHT stuff, so I'll put that on and stick it in front of a heater. It's nice enough, but I've still not found a finish I really like - or that seems as durable as that from the factory. All of the paints I've tried so far seem to be only a few microns thick when applied, unlike the factory stuff which looks more like powdercoat. Ah well . . .

And then there's the cost. When I asked the shop a week or so ago, they said they couldn't give me an accurate estimate 'cos they hadn't kept a proper record of the amount of hours that had gone into the engine - but they did mention something like 15 (yes, fifteen) man hours. I have to admit to struggling not to go berserk at that point - it didn't take me that long to pull the thing apart and rebuild it when the cases came back from being dipped. And considering that labour alone is around £50 p/h, I could see a staggering bill coming my way. But I kept my temper - and good job too. As I've said before, they're good guys and so I was very pleasantly surprised to get a bill for a total of half the previous guestimate when I picked the engine up late this afternoon. Now I admit that still doesn't sound cheap, until you consider that it included the cost of all the labour, an entire new set of journals, plus a new gasket set, plus a bunch of little bits, plus taxes. That's gotta be a bargain in anyone's book - and given that I'd budgeted more than I paid (and knowing that they must've undercharged me) I gave them a good few quid towards their Christmas party. It's not that I've got money to burn, but little things like that can go a long way - and you never know when you'll need to call in a favour.

And since my last visit I've rebuilt the wheels, which turned out to be a whole lot more straightforward than I'd thought it would. With the help of lots of research and reading materials, together with a guide I found on YouTube, I made a half decent job even if I do say so myself. In the end I bottled out of trying to get the tyres off/on again myself and took the wheels to a local tyre dealer. Turns out one of the guys there runs old bikes (he's got a Greeves amongst other things) and when I took the rebuilt wheels back in, he asked me where I'd got them done 'cos he was so impressed with the results. Funny to see the look on his face when I told him that it was all my own work.

That's all for now. As I said, the new engine paint is drying/curing and then it should (he says) just be a case of putting the jigsaw back together. Photos to follow.

Thanks for sticking it out . . .

Neil

HondaMan · « **Reply #101 on:** December 09, 2008, 08:11:17 PM »

Gettin' anxious to see it back together!
Mine, too. I've got 3 apart at the moment, and a foot of snow just set in for Winter.
Sniff.

kpier883 · « **Reply #102 on:** December 09, 2008, 08:30:33 PM »

I just read this whole post from start to finish. Sometimes I can't figure out how I miss a thread entirely when I rarely go a day without signing in. Anyway, thanks for posting all the details and pictures. I am really looking forward to see how this turns out. It sounds like you are going to have a really great ride when you are done.

KP

andy750 · « **Reply #103 on:** December 10, 2008, 04:42:41 AM »

Sounds like you got a bargain with the engine work - it dosent sound expensive to me (and Ive had work done in the Uk and the USA so can compare). I am also looking forward to see you putting it back together and looking forward to that first ride report!

good luck!
Andy

the-chauffeur · « **Reply #104 on:** December 10, 2008, 02:02:11 PM »

Thanks for the kind words fellas. Nice to hear from you all.

So the rebuild has started - and I've already got a couple of questions. It's one of my least favourite parts of the engine - the gearshift assembly. Too bloody fiddly for my liking.

When I got the engine back, it was in what I thought was neutral . . . but that thought only lasted until I tried to fit the external shift mechanism, which seemed to be in completely the wrong orientation.

So this is about as far as I got. As far as I can gather, the position the drum is in now should be neutral-ish (with the shortest of the five pegs hidden by the shift fork). I know it's a bit of an ask, but does that look right? And I think I may have asked this before, but when the bike is in neutral and the rear wheel is turned, should the engine make a loud clicking noise?

TTFN

Neil

HondaMan · « **Reply #105 on:** December 10, 2008, 07:24:00 PM »

It may not quite be in neutral, if the gear dogs are clicking against one another. I hope you still have the cover for the drum's pins? In the picture, it looks to be slightly toward 1st gear, still. It should center nicely between the shift arm tangs when it's right on neutral. Or any gear, for that matter.

Also, try shifting through all gears up, then back down, then find neutral, to see if the gear dogs release each other. It's pretty hard to reassemble with spacers in the wrong places on this tranny, but I'll take a look at one of my out-of-the-cases gearsets to see if possibly an out-of-position spacer might cause off-center spacing. I honestly don't remember if it's possible to put it together wrong and still get it inside the case! There certainly isn't a lot of 'extra' room in there...

the-chauffeur · « **Reply #106 on:** December 13, 2008, 02:06:57 PM »

Thanks HM. Yup, still got the pin cover, and that whole section is back together.

I think I'm paranoid about the clicking. I can't work out what it is yet, but I figure that the main reason I hadn't noticed it when I got the engine back from the shop was 'cos I hadn't attached a chain to it. I'll leave well alone for now.

Spent the day putting the rest of the bike back together, and after about 6 hours, all it really needs are the side panels and seat back on. Cosmetically, anyway.

The electrics are another matter. Tried the old coils for the hell of it - nothing. Put the brand new aftermarket coils in, and can't seem to stop blowing fuses just by turning the key in the ignition. I'm assuming this is a sign that some power is getting through the ignition system, although it's clearly not right. So riddle me this - do the coils have a specific polarity (i.e. have I wired them up back to front)? The replacements I've got don't have colour coded wires (blue, yellow and black-white) - they just have black and black-white.

If I can get this bit sorted, it could cough back to life sometime tomorrow . . .

the-chauffeur · « **Reply #107 on:** December 14, 2008, 07:33:31 AM »

Ha!! Success (of sorts). It lives!

After some wiggling of wires and twiddling with the coils, the bike finally coughed into life earlier today. The trouble with the coils turned out to be a short that was jumping through the thin plastic boots covering the point where one of the feed wires enters the coil. Put that right, and with big, fat sparks all round, the bike barked and ran for a couple of minutes - albeit with revs all over the place. Great news, I thought.

Now for the tidying up. Firstly, I'll need to get the revs under control. I haven't had time to look too closely at the settings yet, but the first thing I need to do is get them down from 3-4k to something a bit more manageable - and strangely the idle screw didn't seem to make any difference when I tried it. I'll balance the carbs when they're closer to being normal.

And while we're on the subject of carbs, I have a feeling the floats need work. Having put fuel into the bike for the first time in a very long time, I've found that if I don't switch the tap to the off position, at least 2 of the carbs leak out of the overflow nipples. And of course I found that out when petrol splashed onto the nice new engine paintwork. Genius. Anyways, I'm assuming the overflow means that the float heights are wrong (there don't appear to be any cracks or splits in the carb bodies/float bowls) - on that note, anyone now what the float height should be? I can't find any measurements anywhere; both workshop and Haynes manuals mention a gauge, but not what the gauge dimensions are.

Weather's too crappy for photos, but I guarantee they'll follow. I gotta say it was nice to hear life come back to the bike. Not far to go now . . .

HondaMan · « **Reply #108 on:** December 16, 2008, 08:48:06 PM »

Oh, yeah, the carb goo....
After you get the float needles and seats clean, make sure the tiny vents are open (look around inside the bottom of the carb, there's several in each one), use a slim wire to push through and then spray through. One that's tough, and often clogged or partially so, is the one that goes from the air horn (a tiny brass hole), forward a bit, then down a bit, then forward to the mainjet emulsifier tube. You'll have to take the mainjet holder out and use a good light inside there to see the wire you must push through from the air horn end to this center area, and spray clean. Even a partial blockage in this one will cause gas-fouled plugs. It comes from mixing old, dried gas and moisture, makes a white powery paste in there. If you ride once a month or more, it never happens: let it sit 2 years and it can close right up.

The fast idle: check the ignition timing with a timing light. Even a few degrees too much will make them idle at 2k-3k.

754 · « **Reply #109 on:** December 16, 2008, 09:00:31 PM »

Or the throttle is hanging up, make sure cable has a tiny bit of slack..

is it just me or does anyone else think that the engine was dragging simply because a few shells got mixed up...?

the-chauffeur · « **Reply #110 on:** December 17, 2008, 06:39:30 AM »

Nah 754 - you're not alone. Me included. But TBH, I'm a lot happier knowing that all of the shells have been changed. Hopefully, that's the last time they'll need any attention for some considerable time.

But - and it's a big but - I'm really not happy about the clattering noise from the engine block when the bike is in neutral and the rear wheel is held stationary. It emanates from the area just behind the drive sprocket (and no, it's not the drive chain) and it desists when the clutch is pulled in, but returns when it's let out. My guess is that there's something still not right in the gearbox. I can't imagine how it would get this way, but it's almost as though there's a mis-alignment of one or more of the gear cogs.

<cue lots of head scratching>

the-chauffeur · « **Reply #111 on:** December 18, 2008, 10:57:19 AM »

Well, that's a relief (kinda). The clattering noise is the clutch pack. How do I know? Take the clutch pack out . . . no noise.

I'm thinking that the friction plates are creating a little too much friction and aren't releasing fully. They're in oil right now, so I'll refit them when they've soaked for a while and we'll see how that goes.

Electrics are all done as well, which is a good thing. And even better, I found a used set of bars on fleabay (pre-drilled originals) - so they're fitted too. Looks sleek with no wires poking out. About the most complicated job remaining (other than the clutch) is balancing the carbs.

Yay

HondaMan · « **Reply #112 on:** December 19, 2008, 09:33:04 PM »

You can measure those plates for warp: get a piece of flat plate glass and lay a plate (either steel or cork) on the glass, try to slide feeler gauges under it where it does not touch down to the glass. The max warpage is .007", but at about .004" they will cause a bit of drag anyway. If you have more than 3 total plates (steel or fiber, added together) that are warped .005"-.007" each, then you will have some stiff-ish gearbox issues, especially when the engine is hot.

the-chauffeur · « **Reply #113 on:** December 20, 2008, 08:03:32 AM »

I'm going to go and sit in a quiet room for a very long time. It's not the clutch.

It's the gearbox. The dogs in gears 2,4 and 5 don't mesh properly. It's either wear (unlikely) or a badly seated circlip. Either way, the engine needs to come out again.

<*sigh*>

HondaMan · « **Reply #114 on:** December 20, 2008, 08:49:58 AM »

Quote from: the-chauffeur on December 20, 2008, 08:03:32 AM

I'm going to go and sit in a quiet room for a very long time. It's not the clutch.

It's the gearbox. The dogs in gears 2,4 and 5 don't mesh properly. It's either wear (unlikely) or a badly seated circlip. Either way, the engine needs to come out again.

<*sigh*>

I cannot think of a circlip that would cause this, unless it was simply not set into the groove at all. Was the transmission disassembled, with gears off the shafts?

Wear won't do this, with the exception of a damaged groove tip on the shifter drum itself. This defect would not push the gears far enough away from each other (for the affected shift fork), which could then cause this issue. A severely bent shift fork can also cause it: the most common malady is the one that hangs down during the upside-down bottom case reassembly: I have seen it get bent if it was not guided properly into the gear's track, and then the cases were bolted together. So, it may be time to check the drum and forks. Also, if one of the pins inside the fork(s) is cracked or broken, reducing its diameter significantly, this can have the same effect as the above-mentioned bad groove in the shifter drum.

All of these events are rare, usually occurring only during engine (mis-) reassembly. A bent shift fork is even rarer, unless the bike is raced and shifted often without the clutch. It's one of the toughest bike transmissions ever built!

the-chauffeur · « **Reply #115 on:** December 20, 2008, 04:38:28 PM »

To my knowledge, the transmission wasn't disassembled. I sure as hell didn't pull it apart - when I pulled the bits out of the crankcases, I kept everything in its mounted state and just lifted the shafts out. I guess it's possible that there's a damaged groove tip, but for the life of me I can't think how it would've happened. Same with the shifter forks. I know that the shop guys checked some of the tolerances, so it's possible that they took some of the transmission apart - and looking at the (somewhat unpalatable) alternatives, I'm guess I'm hoping that it's the circlip.

I think I'm pretty much screwed if it's a damaged part - haven't seen any gearbox internals show up on fleaBay over here for a while. S'pose I might end up having to import something, but for now I guess I've just gotta put my head down and get on with the disassembly again. I'll have to see if I can beat my previous best of 5 hours (inc. bagging and tagging).

Small consolation for now is that the top/bottom ends sound great. No cam/drive chain noise, and a great exhaust note. Oh, and I'm off work for the next two weeks - and the shop guys are gonna sort it once the engine's out. But it's gonna to be hard going.

the-chauffeur · « **Reply #116 on:** December 21, 2008, 08:31:52 AM »

Four hours - from fully built to engine in the boot of the car.

*yawn*

HondaMan · « **Reply #117 on:** December 21, 2008, 09:42:44 AM »

I've got a couple of trannys if you need a piece or two.

Magpie · « **Reply #118 on:** December 21, 2008, 10:01:13 PM »

This has been bugging me for some time and after many glasses of red wine I have a couple of questions. Are you sure it's inside the motor? If it is ignore my ravings. Sorry to bother you.
Was there a clicking noise when you turned the motor without the chain on? Did you change the primary sprocket? Is the primary cover the same one as you started with? Was the chain adjusted tight? Was the primary cover on the motor when you noticed the noise? Why? Because I had a similar clacking noise when I installed my motor and used a different primary cover. The chain was clacking against a post-like thing on the inside cover of the primary. A bit of work with a file stopped the noise. Maybe this is what's going on here. You say you have the engine in the boot of your car, can you remove the spark plugs and use the kick starter to turn over the motor? Will it still make the noise? If it does still clatter, my apologies for bringing this up.
As Hondaman says, I too have a number of transmission parts and shifter forks if the need somes up.
Good luck,
Cliff.

the-chauffeur · « **Reply #119 on:** December 22, 2008, 05:07:28 AM »

Thanks guys - the offers of help are very warmly received. I'll let you know what the diagnosis is in due course.

Maggie - with the chain off there was more of a dull knocking noise, which is probably more to do with the slow speed of hand turning in the absence of any other means of drive. The chain was adjusted, but not tight - and all of the covers that needed to be off were off (IIRC the only sidecover that stayed in place was the alternator cover). I know the post-like thing you're talking about - it's a chain guide that should have a rubber sleeve on it - but the cover that it's mounted inside was off when the engine was running. It definitely wasn't chain lash.

Believe me, it's the gearbox internals. In the process of fault finding, I removed practically everything I could from the outside - and it's one of those things that you can really hear if you stick a screwdriver onto the cases and put your ear to it (using it like a stethoscope). Not that I want to make excuses for anyone, but what seems to have made it harder to detect when the engine was put back together last time is that doesn't happen when there's no counterweight on the drive shaft i.e. the clutch pack - and I'd taken the clutch pack out before I dropped it off at the garage last time to save weight (and to make sure no bits got lost). This time I've left it in place.

It's now just a case of waiting . . . again.

More news as it's made

the-chauffeur · « **Reply #120 on:** December 29, 2008, 04:46:04 PM »

It's an update, Jim, but not what you'd be expecting if you've been following this thread . . .

. . . if you hadn't guessed, I'd been getting bored with waiting for the return of the completed 750 engine. Added to that, I know from all the practise that I've had recently(!?!) that it'll only take me a few hours to rebuild the bike once the engine's back. Pretty much everything is fit to go back on, and although it may not be cosmetically perfect, it all works very well and looks very tidy. Soooo . . .

. . . I've just bought something else to work on. It's a Honda, and it's the same age as the 750 ('72), so it sort of qualifies for mention on this board, but it's a DOHC - specifically a CB450. Why a CB450? Well, whilst they may be a relatively common site in the US, they were never officially imported into the UK, so there aren't many of 'em about over here. Added to which, it's a parallel twin, which is an engine I don't have in my collection right now (collection, he says - makes four sound like some kind of museum).

Anyways, here it is . . .

It looks very sound and apparently it's only got around 10k on the clock 'cos it's been standing around for a bit. The only major downsides are that it's not yet registered in the UK (I'm trying to work that bit out) and I haven't actually seen it yet 'cos it's 250 miles away.

Still, it should give me something else to do when it arrives.

More on the 750 as soon as I hear something . . .

the-chauffeur · « **Reply #121 on:** December 29, 2008, 04:47:30 PM »

- oops - duplicate post -

HondaMan · « **Reply #122 on:** December 30, 2008, 05:19:57 AM »

Just one look at that beautiful example of the "big twin", and you can see the heritage of the 750K0. Rear brake, seat, grab rail, styling...

the-chauffeur · « **Reply #123 on:** January 01, 2009, 01:03:50 PM »

Thanks HM. Just found a post of yours copied onto another forum about 450's. Didn't realise you were such a fan. I'll be sure to post some better photos when it arrives, although it sounds like I'm going to find myself in something of a bureaucratic nightmare 'cos without any papers I can't prove that import duty has been paid on it (effectively it's got no title documents). Ah well, it'll be a learning experience if nothing else . . .

But whilst things are at a standstill, I've got a question about breather hose routing on the 750. Having searched the forum for breather hose routing, about the best I came up with was this - http://forums.sohc4.net/index.php?topic=685.0 - which kinda helps, but seems to have some differences from the routing on my K2. The outlets that are confusing me are the one on the rear of the rocker cover and the one at the rear of the upper crankcase.

Having just had a look at the K2 oil tank, it's got 2 entry/exit points on the rear - one at the top (into what I assume is a separating chamber) and one much lower down. If I'm reading the diagram in the page linked to above correctly, the rocker cover outlet hose should go into the connecting point on the upper rear of the oil tank. But at the same time, it seems as though the lower entry/exit point should go to atmosphere. If that's right, what does the rear crankcase exit point connect to? The diagram seems to suggest it goes into the airbox (or something close) but since my airbox is hidden under a bunch of other parts awaiting the return of the engine, I can't check if I'm reading the map upside down . . .

Thanks in advance - oh, and Happy New Year all

Neil

754 · « **Reply #124 on:** January 01, 2009, 08:22:38 PM »

Nice Double_Knocker..

You can alway vintage race it or display at shows.. nice piece of living room art!

The tank stripe almost looks to me like a different one than we had in NA, might be wrong tho..

Skinny line on back of 750 motor goes to skinny fitting on oil tank. Valvecover breather goes behind motor , points to ground. I think the big one on that seperator thing on tank goes towards the ground too.

News:

Author Topic: Keep telling yourself - a restored 750 K2 is an investment (Read 38569 times)