Author Topic: 1975 Honda CB400 Four Project - Rookie  (Read 317191 times)

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Offline Godffery

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #425 on: August 16, 2011, 07:41:28 AM »
It dose sound like a pilot jet issue; if the pilots are larger then what came stock, I recommend going back to stock with those.  The only time increasing the pilots seems successful is with race bikes because they usually remove the chokes and fatter pilots makes them a little easy to start, plus there ran flat out most of the time and the idle is set Rather high. 
If your pilots are actually same as stock, then drop the clip on your needles one notch.

As for the HP; Photolar hit the nail on the head. Manufacturers liked using HP rattings from the crank because it sounded much better in there brosures then the lower result of testing it from the rear wheel.

Offline Hush

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #426 on: August 17, 2011, 09:45:17 AM »
More riding, less fiddling Rick. ;D
You are falling into the SOHC4 trap of spending more time wrenching and less time actually enjoying the bike for what it is.
As you say the bike is all pretty much brand new so maybe a few miles on her will sort some of your issues out it will also get you used to her little personality defects. :D
Does sound like carbs though.........Hush.
I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

Offline RickB

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #427 on: August 26, 2011, 08:54:19 AM »
Thanks for the words of wisdom guys.

@ Godffery, your carb advice sounds solid. Thanks.

@ Hush, I hear what you're saying about the tinkering. Don't worry, I've been riding it like a bat out of hell (photos below!).

@ Photolar, you are correct, that HP rating I got from the spec sheet here on SOHC4.net. That is probably at the crank so 31HP isn't all that bad I'm told.

Ok so some updates...



Firstly, the riding. Me and my two mates went on a great trip up to Marysville, around Lake Mountain way to Warburton. It is really an incredible part of Victoria that I'd never been too before. And the roads... Wow. It's like a video game in parts; ferns and tall gums over-hanging tight corners and flawless roads. It was incredible.

Without having anything to compare to, I feel the bike handles great. Brakes, acceleration, cornering, suspension were all performing well I thought. No surprises (except for some badly timing down shifting on my part that was a little scary coming into a corner).

I tried really hard to let the bike run at higher RPM's (6k-7k RPM) and not be afraid of the 6 speed gear box.



Smiles all 'round. We'd just pulled over to talk over a particularly fun part of the trip. A very fast looking Lamborghini had just sped past us.









So I finally sorted out my tail light situation. I bought a NOS Lucas L488 over eBay. The rubber was a bit split in places and the globe mount borderline antique but it all works (eventually I'll have to buy the new version they make and replace it). I think it looks perfect and really ties the back end together nicely.

As you can see, I still haven't had a chance to have the seat upholstered. I just really can't stand to be off the bike for the time it will take to have done!





For the license plate holder I just cut off the front plate from the Lucas type mount I had bought years ago and bent up some aluminum to hold it off the rear frame hump. It's not graceful by any means, but I really couldn't think of a better way to mount it. Fixing it to the seat with resin perhaps? I really should have made that seat out of alloy!



Speaking of things that should be alloy, a mate cracked my side cover when we were off loading the bike from his ute. Bummer but the plastic is quite brittle with age so it was bound to happen. For now, I'll just deal with it but a respray and color match will have to happen.





You may recall me saying a while back that the chrome on my muffler had been ruined from an overflowing/overcharging battery on my first ride. Here's some close ups of the damage to both the muffler and the center stand spring that was in the path of the overflow tube. Some acid ended up on the rear hum but it didn't do much damage, just some light pitting in places. The above damage does not wash/polish/buff out. It's permanent.



I know it's months overdue but one of you blokes asked for some close ups of the muffler as it is a cheapo Norton Commando replica from eBay fitted to the stock CB400F headers. Here's the old ruined join.





And the new replacement one. Same thing really. Basically Matt The Mechanic cut off the existing smaller mounting pipe from the muffler and welded a bit of stainless tube on at a slight upwards angle. Then on the stock header collector box he had to weld on a larger pipe mount so the pipe would slip on the right way for flow. So it does alter the stock collector but I love the result. Obviously I have to clean up the welds and apply a little touch up rust proofing where the chrome burned off.







Had to get a mirror for the safety inspection. I went with the rectangle style and I think it works. Not subtle, but I really don't like the droopy bar end look for some reason. Posh make a non-adjustable version that would clean it up further, but it was twice the price and the shop didn't have it in stock at the time. This will do for now.





Finally found some 5mm adapters for a borrowed carb sync tool. Looking forward to getting this done.



You were all right. Clubmans are the poor mans clipons. So I bought clipons. Timbo highly recommended the Woodcraft ones but nothing else on this bike is billeted and I wanted to keep it that way. So good ole' steel it is.





I also got a spare top triple tree from 400FourBits.co.uk for ten pound. I had it filled with weld at the local body shop (which took almost three weeks...) and now I'm trying to cut it down. The cutting discs/grinder I had wasn't up to the task, so I'll have to try again tomorrow with the right tools. Then it's off to the powder coaters along with some other bits and pieces (finally going to cut off the rear passenger foot peg mounts I think).

That's it for now.

Rick.
« Last Edit: August 26, 2011, 08:58:56 AM by RickB »

Offline Godffery

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #428 on: August 26, 2011, 01:08:50 PM »
Hmmm, I'd be really surprised if that top triple tree isn't warped now from the heat of having it filled with weld.

Sorry, you probably didn't want to here that.  = /

Offline tom8Toe

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #429 on: August 26, 2011, 02:05:17 PM »
I didn't have it taken all the way down, but here's what my tripple looked like after it was filed and polished.

-Chris-

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Past Rides:
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'72 BSA A75 Rocket3 (Sold)
'65 Honda CB450 Black Bomber (Stolen, never recovered)
'89 Honda GB500 (Sold)
'75 Honda CB400F (Sold)
'08 Triumph Bonneville T-100 (Sold)
'14 Triumph Scrambler

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Offline RickB

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #430 on: September 06, 2011, 12:45:01 AM »
Hi guys,

So I finally did my carbie balance/sync. It was quite difficult with the twin vacuum gauge I had. I would do 1-2, then the idle for 3-4 would be super high. I just couldn't get it right. In the end, I did the best I could but I think a 4 dial gauge is the way to go.

Until then, more bits and pieces:







I don't think it's warped. Or at least it looks straight. I got a cutting disc, a grinding disc and some sanding disc and put it in a bench vice and went to town. The thin cutting disc worked the best, along with the sanding disc. The metal is quite soft so it was easier than I thought. The hard part was smoothing it off afterwards.

In the end I decided to fill it with resin and some body filler for the holes where the welder missed. I regret this now as the powdercoater said they can't powdercoat resin/filler because it just boils off from the heat. So now I'll have to paint it to match the frame. Not the worst, but another unexpected problem.







This is continuing on from the Norton Peashooter muffler mounting photos above. This is the custom bracket my mechanic made up that connects the muffler to the stock mounting bracket. It's a bit rusty because I rode it a few times without painting it. It's now at the powdercoaters.



You can see here where the high pressure water cleaner at my local car wash stripped the chrome right off my cheapo Thailand chrome spokes! Do yourself a favor, spend the extra money and buy stainless spokes. The poor man pays twice as now I have to take the wheels and tyres off and send them off to be re-laced with stainless spokes. Lesson learned.









Just showing off a little bit here. I have dropped the seat off to the upholster finally, that should be interesting when I finally get to see it. Brown leather tuck n' roll, like the Nitrohead seats but without the press studs.

I have yet to do things like re-torque the head, carbie sync, grind off the rear swingarm passenger peg mounts as one is missing because of the muffler, install clip ons, polish/clean, changing some bolts/springs for NOS parts, figure out how to install fairing, paint fairing, repair side-cover, decals and repaint.

However, for the most part, it's done. I deliberately took the above photo in the same place I took the first photo years ago.



Before - May 24, 2009.



After - September 06, 2011.

Thanks again for all the help over the years guys, couldn't have done it without you all.

Rick.

Offline MoMo

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #431 on: September 06, 2011, 02:22:53 AM »
Rick,  Very nice...Larry

Offline -CB-Jamie-

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #432 on: September 06, 2011, 03:06:44 AM »
Looks well Rick, Pity about the spokes, I have them too on my project.
Jamie
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Offline fastbroshi

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #433 on: September 06, 2011, 03:53:02 AM »
Alrighty then.  Where's the next one?  :)
Just call me Timmaaaaay!!!

Offline RickB

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #434 on: September 06, 2011, 08:41:11 AM »
Haha, thanks guys.

Jamie, don't use a high pressure car washer thing on those spokes then. It ripped the chrome off straight away.

Fastbroshi, the next one? Well now that I'm living in the US (and the 400 is in Australia) I was thinking I might tackle a CR750. I'm excited about not having to pay $30+ for shipping anything. I'm currently on the lookout for a relatively unmolested but too far gone CB750K2 or K3 that I won't feel guilty about chopping up.

I can't wait to get stuck into that thing!

Rick.
« Last Edit: September 06, 2011, 08:44:34 AM by RickB »

Offline Doctorlumen

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #435 on: September 12, 2011, 10:02:49 PM »
Well done, Rick. She really came about with style.

Just wanted to mention a couple of things about the way your carbs are performing, as your symptoms sound a bit like issues I've been chasing. Firstly, you may need to get used to hearing "be happy with what you've got, shes an old bike" speech. I have heard it alot over the years of owning my 400f. I grit my teeth every time I hear it...but really I couldn't be happier with my bike.

Specific to your performance issues at temp, here is what I've learned by trying and reading everything I could find on the topic:
 An idle that "hangs up" when warm is said to be a bit rich. My idle rises when warm for sure, but you should be able to blip the twistgrip and have it rise and fall accordingly. Rick Denoon on the yahoo group recommends dropping the idle jet to a #38 (two points down from stock?) and I concur after trying it myself. Also, Ensure your needle clip is in the middle slot...though bumping one notch richer makes the midrange feel stronger on short rides, you wind up rich once the temp gets up there. Tons of folks I know who have built, owned, and raced 400fs longer than I've been into motorbiking swear there is nothing truly to be gained in moving that needle on most bikes.
Once you start getting into cam profiles and big bore kits, the needle becomes more important
Always the tinkering fool, after trying a bunch of the notches for fun, I'd tend to agree.
Those idle adjust screws really should remain in the "2 turns" range no matter what the final jetting. Again, I've learned from tinkering. Same with the floats....22-25mm. A small change here will affect quite a bit, especially at idle and slow speeds.
Finally, the main jet is the real meat and potatoes in the system...and pretty easy to swap without pulling the whole rack of carbs. Most folks I know/have read about run a jet in the mid-to-high 80's with an open pipe and pods. My bike loves a #98...the carb bodies are bored, I use pods, and have a fairly restricted Marving "classic" pipe. I peaked at 31hp and 26ft/lb torque before I had the carbs bored out...not sure what she has now. My point is, every 400 is a bit different, but all seem to react well to broad steps in the main jet. I would recommend starting with that #38 pilot, as that cleared up most of my low speed, high temp richness. She isn't as crisp as a modern bike, but this change helped a ton. Then start swapping the mains.

Also, consider advancing the ignition a bit further...I got that last hp by twisting the advance plate a tad and it cleaned up some of my higher temp "gurgles" as well.
Once the jetting and high temp richness is dialed in, try treating yourself to a quick-turn throttle tube to deal with the flat spot at take off. I haven't got one yet, but have been told it helps immensely with the lag between 1100 and 3000rpm. Hope this long winded post helps you sort your ride out! 

Offline RickB

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #436 on: September 20, 2011, 01:07:30 PM »
Doctorlumen,

This is tremendous help, thank you! I'm basically going to try everything you've suggested. I'm like you, ok isn't good enough. Not when I've come this far. I want this thing to be the best it can. Plus, I enjoy the tinkering.

Can you suggest a good place for me to buy OEM Honda carb parts? Specifically idle and main jets. I've been told to stay off the Keyster kits so I think buying Honda is the only way to go.

Rick.

Offline -CB-Jamie-

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1975 Honda CB400 Four Project - Rookie
« Reply #437 on: September 20, 2011, 01:13:25 PM »
Rick David silvers has oem jets for the 400's as far as I know
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Offline Doctorlumen

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #438 on: September 20, 2011, 08:11:08 PM »
I honestly recommend bike bandit for the jets at least. I don't think DSS even has those smaller pilots. And neither did sudco last I tried.

Good luck and report back! I'm curious to see how your bike takes to the settings I'm running.

Ping me with any questions!

Offline -CB-Jamie-

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #439 on: September 21, 2011, 01:34:14 AM »
Sorry didn't realise you were talking about dropping the jet size, David Silver has the standard size jets alright.
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Offline RickB

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #440 on: January 23, 2012, 06:38:41 AM »
Hi guy,

So after what feels like a year away from the bike, I'm back home visiting and have been getting the bike prepped for a trip with the mates this weekend. Lots of photos to come.

Part of what I needed to do was re-torque down the head as I was getting a lot of oil leaks and it was a freshly rebuilt engine so needed a re-torque now that everything had bedded in.

Anyway, on reassembly I ran into trouble. The middle upper left rocker cover bolt started giving me that dreaded 'no resistance' feeling. I immediately stopped, pulled the bolt out and my worst nightmare had come true.





I have no idea how I stripped it, those bolts are only about 8 ft-lb of torque and I hadn't even gotten to that yet when it gave way. I've never had a bolt pull out a neat spiral like this either. Is this what they call a helicoil? A gift from the previous owner perhaps.

So what should my next course of action be? Do I need that bolt? Would the other three be enough? Obviously I have to fish out whatever mess is left in the hole, but will it damage the engine? Do I need to rebuild it again?!

I'm devastated.

Rick.

Offline jessezm

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #441 on: January 23, 2012, 06:59:12 AM »
Rick, this is really uncanny--
   On Saturday afternoon I retorqued my head bolts as well, as I have just hit 120 miles on my fresh top-end.  I also had a very slight weep at the base gasket.  On putting the cam cover back on, I stripped the EXACT bolt that you did--same one out of the 4!!!  It felt and looked exactly as you described, so I doubt that was helicoil.  The threads came out in a coil just like that.   I had also used very little torque, and I too was flummoxed.

I picked out all the bad thread and there was still a little bit of grip left, so what I did was just reassemble everything except for that bolt, and then I put it in last and went just over finger-tight, and it snugged up ok.   This is just temporary for now, and I do think that a longer bolt might work there in fact.  But I can report that I've got no leaks or problems thus far after doing that, but I was only able to ride another 30 spirited miles before it rained the rest of the weekend.  If you can find a slightly longer bolt I think that's the quickest/easiest solution.  The 3 other bolts, plus all the other ones that hold down the cam cover, should be plenty.

How strange is it that we both stripped the same exact bolt on the same day doing the same thing???




Offline jessezm

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #442 on: January 23, 2012, 07:00:21 AM »
Oh, in better news, however, the oil weep is gone!

Offline strynboen

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #443 on: January 23, 2012, 07:14:11 AM »
mine 550 did the same thing..i heli coiled them..and was running same day
i kan not speak english/but trying!!
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Offline RickB

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #444 on: January 24, 2012, 05:21:04 AM »
Thanks for all the great advice guys.

Jesse, good to hear from you mate. How's your rebuild running? I have been following your ups-and-downs. Likewise your quick advice allowed me to sleep at night, thank you! So funny that we both did the exact same thing. I remember at one stage we both had the same switch gear too. Sister bikes from different countries! Anyway, I don't feel like such a noob for screwing up, you've pulled your fair share of engines apart and know what you're doing and it still striped. It can happen to the best of us.

I took your advice and cleaned out the thread as best I could (most of the big stuff came out with the bolt as you can see) and tightened it down as much as I dared. It is more than finger tight but has some play with a spanner on it.

As it's quite easy to get to (just take the breather cover off), I think I'll go looking for a slightly longer screw tomorrow. Might stick a long one in, measure how much is sticking out and work out just how deep the thread goes and find a bolt that is as long as possible. I'm a little concerned as those four bolts essentially hold the cam shaft in place and I certainly don't know enough about engines to even want to take a chance with that!

A helicoil is obviously the long term solution, but where it's located (right under the coils/frame) I think it would require taking the head off just to get to it, even if someone could drill a helicoil in straight enough.

Once I got the rocker covers all back together I then moved onto the next step in the manual... Setting the tappets (valve clearances?). That was a time consuming, fidgety, frustrating chore. There has to be a better way of doing that? Two cumbersome spanners and a flimsy feeler gauge is torture! Any advice for me?

Thanks again for the help guys, couldn't do this without you lot.

Rick.

Offline jessezm

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #445 on: January 24, 2012, 05:45:42 AM »
Well I for one hope we, if not our bikes, get a chance to meet some day!  It does seem like our builds have had a parallel track! 

Anyhow, sounds like you have things sorted with the bolt for now.  Really I think you won't need to worry about it for a while--just don't forget about it next time you dig into the valve cover!  You can ride for a bit and recheck your valve clearances to assuage your worries about the cam, just make sure you check them with a totally cold motor so you don't throw yourself off.  I rechecked mine yesterday and they were right where I left them.

Anyhow, about the valve adjustment pain--I find it is MUCH easier to do with the coils and horn removed and breather cover off--there's just more knuckle room-- so doing it right after re-torquing was a sinch.  You're right that it's hard to get in there, but this is what I do--use one spanner (9mm) for the locknut and just a simple needlenose plier to hold the top of the tappet in position.  I watch it's position to make sure it doesn't move when I'm ready to do the final tightening.  You get a real feel for the feeler gauge and the amount of play you need and it gets easier each time you do it.  Good luck!


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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #446 on: January 24, 2012, 08:42:11 AM »
Great looking bike Rick!
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

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Offline RickB

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #447 on: January 29, 2012, 11:22:23 PM »
Hi everyone,

It's been a big week for the bike. I spent all last week preparing it for a 400 odd mile trip down the Great Ocean Road.

Firstly, I ran the bike with the aforementioned striped rocker cover bolt hand tight all weekend and it seemed fine. I wasn't holding back either! My eyes start watering before the bike stops accelerating but I'm pretty sure I got her up to top speed of 100mph. Regardless, I'd like to get that slightly longer bolt in this week.

I've got a bunch of photos and updates, but I'll take it one at a time. I've been dealing with an oil leak since I got the engine back in the frame. Finally got around to taking the rocker cover off and getting stuck into it.





Took the rocker cover off. This was one of the more intimidating things I've done on the bike. I had never opened the engine up before and was reluctant to do it without qualified supervision. However my mechanic was moving house and didn't have time for me. He gave me plenty of instruction, an encouraging word and the sound advice of "don't be scared when you see the price of a decent torque wrench". True words I would discover.



So the purpose of all of this was this pillar nut. I suspect this is where my oil leak is coming from because Matt, my mechanic and the talented man that put this ragged engine back together, was never able to get those rubber ringed washers that go under these nuts to seal right. In the end we had this area machined to try and flatten the surface it sits on flatter as it had been damaged.











So in an effort to seal this area, Matt fitted the standard copper washers and added some sealant in an attempt to hold the oil at bay. It doesn't appear to have worked. So I cleaned the area up and installed new stock rubber ringed washers to see if they could do it. No is the answer, I still have oil coming out from the general fin area, more so on the left side.

One thing I don't understand about these pillar nuts is this. You torque the nut down to 18ft-lb (I actually went a little tighter to 19ft-lbs), then you're told to torque the rocker cover bolt into this pillar nut at 8ft-lbs. That essentially means you're lifting that pillar nut up 8ft-lbs, meaning it is only torqued down 11ft-ilbs. That seems like a silly design and an obvious area for leakage.

Has anyone else had oil leaking that you suspect was from these two pillar nuts? Were you able to fix it?

Thanks,
Rick.
« Last Edit: January 30, 2012, 12:10:25 AM by RickB »

Offline jessezm

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #448 on: January 30, 2012, 05:34:39 AM »
Rick,
  When I redid my engine I used new washers from Honda for those nuts, and have not had a problem with them.  I'm not sure your logic is right on the torque values canceling each other out, though.  When you torque that first nut down, the torque value is obtained by nut pulling against the threads of the engine stud, and that value is transferred to the face of the nut bearing down on the head (or the washer, rather).  When you tighten down the valve cover, the position of the lower nut on the threads should not change, and if it does, it should be even tighter because your turning the bolt into it in the same direction (and if it does turn, your torquing that valve cover nut way too much!).  Granted this is all my own made-up logic, but I think your problem might be with the sealing washer or mating surface rather than the torque values.

I wish I could help, more.  I would warn against using much sealant on that washer, though, as I imagine it would be easy for some to migrate into those tiny oil jets and cause an obstruction.  How bad is the leak?  Can you get any pictures of it?  I don't recall--did you use a Honda head gasket?

Offline RickB

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Re: 1975 Honda CB400 Four Project - Rookie
« Reply #449 on: January 30, 2012, 05:21:15 PM »
Jesse,

I hear what your saying with the pillar nut pulling on the engine stud. The rocker cover bolt should be pulling on the thread of the stud, and should not lift up. I think you're right in that my leak has more to do with the seal between mating surface between the pillar nut and the cylinder head.

I'll take some photos of the leak area next time I take the bike out (raining here at the moment). I didn't use OEM Honda head gaskets no, I used the kit that DSS sells. I've since read about how unreliable those gasket kits can be, so perhaps that's my problem more so than the pillar nut/washer?

Thanks for the guidance, much appreciated.

Rick.