CL175K0 Build, Barn Fresh-Adjacent

Ready for a test ride. Replaced burned out headlight instrument bulbs, replaced the rear brake light switch with one that works. Remaining is prep and paint of tank, side covers and tool can. I have the race bike tank on there now temporarily, it's an identical tank. Just look at that luscious ten-footer chrome! lol

Can't think of any issues, though I'm mindful that it's miles from home when these test riders balk and refuse to proceed

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stl360+450 said:
Looks good. Is the tire pressure okay? Maybe I'm just not used to those tires.
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Yeah looks odd for sure. New race and old race tire 22 psi whew, the new one's a Bridgestone BT39SS

We like those Avons and such that get so hard and ornery after 40 years that they stop wearing out, they're like wagon wheels
 
Twenty mile test drive successful, out there about 45 minutes before rain resumed, I'm really pleased. Got the idle settled down (needed more enrichment at the slow jet) and it just runs like a sewing machine now. I was having so much fun I didn't want to stop!

I'm geared up slightly so the speedo underreports. A little juddering under heavy front brake, something to inspect.

A little oil weeping from the clutch rod seal, I expected this and assumed when everything got up to heat things like that would present themselves.

Happily, an oil leak I believed was coming from the head gasket has sealed itself, maybe the gasket swelled? I'll keep an eye out.

I'll take the bike out for 40 miles tomorrow and will try to get plenty miles on it in the short term. A 200 mile motogiro day in September up in BC is in this bike's future, and hillclimbs the next day. So if it's in the mood to let a feller down I wanna know sooner to effect repairs. This just in...evidently my turn signals have stopped working (again.) Not excited about messing with the switch, as all of you I'm sure can relate.
 
I thought it might be best to place this post in its own new thread but I couldn't see any category in which it naturally fit. I'm trying to find out if anyone has any idea of the fitment for this awesomely patina'd rear rack a guy gave me. He said it was for a CB77 which would make it fit a CB72 as well but I don't see how it would mount properly on my CB77. Nor on the CB175K6 or CL175K0 for that matter.

The idea looks like it's supposed to mount at the shock eyes and then bolted to the fender, but there doesn't appear any way for the taillight to exist. Any ideas? I don't need this thing, especially if it doesn't fit anything I have.

Rack 1.jpg
 
Wait, this just in....an image search on the gargler reveals this pic of Pirsig's bike, looks like the exact same rack as mine, I still have no idea how it gets around the taillight

Pirsig.jpg
 
The bracket in the center of the rack has a curved part that looks like it should go on top of the fender and bolt to where the taillight is. My guess is that the bracket is sandwiched between the fender and the taillight.
 
boddy said:
The bracket in the center of the rack has a curved part that looks like it should go on top of the fender and bolt to where the taillight is. My guess is that the bracket is sandwiched between the fender and the taillight.
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I agree...I thought the idea was the bolt holes for the fender and the taillight would neatly match up, but I'm guessing only the upper holes on the fender are used. Maybe one needs to drill an additional hole in the fender? Dunno

I suppose my target market is a True Believer endeavoring to build an exact replica of Pirsig's ZAMM Superhawk...I hope riches don't change me
 
Figured there's no reason to delay replacing this clutch rod seal, certainly there's even a reason to be thankful it didn't spit the thing completely out in the 70 miles of shakedown and sea trials

I note the entire exhaust needs to be loosened and eased slightly out if one needs to remove the side cover, so that's an annoying bespoke design feature...no casual peeks at the air filter condition allowed

oil seal.jpg
 
This is the better of the two seats I have so it's a keeper...it's in very good condition, the piping is faded but all there. I don't see any reason not to freshen it up and just keep using it until necessity dictates something different.

Any of you cats have success spritzing some secret sauce or whatnot that gives 57 year old Honda vinyl that showroom shine?

Seat.jpgI
 
Having received no responses to my seat restoration question, we move on.

Prepping the tank for painting, but what's this? I note the YT rabbit hole makes available all manner of crappy videos of guys attempting tank repairs with soldering, brazing, and JB weld. I note most of these gjuys have never soldered anything in their life because they're pushing the solder onto the iron and apparently just trying to glob the area up enough to plug the leak. Have any of you cats experienced a tank repair like I'm contemplating?

Tank hole.jpg
 
I soldered several holes in my tank with a propane torch but after finding yet more leaks I opted to line it with Caswell tank liner.
 
Tony Clifton said:
Any of you cats have success spritzing some secret sauce or whatnot that gives 57 year old Honda vinyl that showroom shine?
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My secret has been spritzing dollars on eBay for a decent replacement seat cover, but yours looks worth the effort. Mine have generally been torn or worse.

I avoid polishing my seat covers. The few times I tried it I was worried I was going to slide off the back of my bike!

Tony Clifton said:
Have any of you cats experienced a tank repair like I'm contemplating?
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I used the JB Tankweld product to seal up some leaks around the crossover tubes on one of my tanks. The leaks showed up after I removed an old Red Kote lining and I then relined the tank with another product.
 
I have soldered up some rust holes with a torch and 50-50 lead/tin solder. Never actually used the tank as de-rusting brought out a lot more holes making the tank unusable. I would de-rust the tank to see what other areas might be "thin". You could probably plug the rust holes with something like plumbers putty while you soak the tank in you favorite liquid.

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boddy said:
I have soldered up some rust holes with a torch and 50-50 lead/tin solder. Never actually used the tank as de-rusting brought out a lot more holes making the tank unusable. I would de-rust the tank to see what other areas might be "thin". You could probably plug the rust holes with something like plumbers putty while you soak the tank in you favorite liquid.

View attachment 56711
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Yeah I was considering that what I can see may just be the tip of a thin rusty iceberg. If I wanted to try out a JB Weld repair, I was considering treating it like you would a hole in drywall, where you can insert an oversize backing plate into the hole and another plate on the outside and sandwich the hole between them. So that would mean enlarging this existing hole, not bad because otherwise it's just crossing one's fingers about the level of rot
 
I've used a piece of fine metal screen material as a backing and just laid it across the hole and solder the whole thing to the tank. Works okay on the underside but not suitable where the patch would be conspicuous.
 
Tony Clifton said:
This is the better of the two seats I have so it's a keeper...it's in very good condition, the piping is faded but all there. I don't see any reason not to freshen it up and just keep using it until necessity dictates something different.

Any of you cats have success spritzing some secret sauce or whatnot that gives 57 year old Honda vinyl that showroom shine?

View attachment 56324I
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Formula 303 Protectant - the marine version. clean prior with a mild detergent, dry well and then soak it down liberally and place in the sun. about every 15 minutes go over it with a light spritz and a microfiber, until it's not absorbing anymore. then dry wipe it, keep it warm until it's not greasy anymore.
 
Mechanically this bike is complete and I'm quite happy with the results. Starts from cold on first kick, idles fine, rides fine. But there is this tapping noise I'm hearing from the top end that is worrisome. I've attached a link to a short video of the bike idling.

 
Update on this build: I tracked the noise down to the cam chain and I fixed that. Now, it starts and runs fine, idles and doesn't smoke and is pleasurable. But....there is an odd rattle that shows up, usually on deceleration. At first I thought it was a loose muffler baffle, but that wasn't present before I removed and replaced the engine this last week so it would seem strange for such a thing to occur NOW. (Occam's Razor and all that.) So I'm wondering. I can only describe the sound as like an intermittent sheet metal vibration, but I've checked and rechecked anything that seems like a likely culprit.

I would think something associated with rings or whatnot would show itself through smoking but it doesn't seem to smoke.

Took the bike on a 12 mile ride today and rode it hard, trying to make the problem announce itself with more vigor or go away. Accelerated through all the gears to 60 mph, no problem. It seems the same. Another puzzle. Still starts on the first kick and idles fine, revs fine, etc.

I need you guys to tell me exactly what's going on based on very limited information.
 
stl360+450 said:
I'm only quoting this because it was funny to read.

Adding to Tom's suggestion, maybe you already checked the heat shields, but what about the internal baffles within the mufflers?
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Since the heat shield and internal baffle seemed the most likely culprits I have spent much time pondering them and it's not the heat shield. I can't tell about the internal baffle, the end of the baffle or whatever piece of metal just inside the muffler is complete and not rotted, it also blocks off and prevents any further review of the muffler's guts. Coming in from the other direction, I could remove the lower pipe from the muffler and see if that's any better, my reluctance to mess with exhaust pipe connections notwithstanding. Still...it sounds like a sound from the engine being blared through the muffler, though I hope I'm wrong.
 
Center stand or side stand vibrating against the muffler? Nevermind - duh - CL, not CB
 
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I remember back in the day that the license plates would crack without a backing plate. Maybe your plate needs a little support?
 
boddy said:
I remember back in the day that the license plates would crack without a backing plate. Maybe your plate needs a little support?
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I thought about that possibility myself, and with only top bolts holding it they often made buzzing vibe noises.
 
ancientdad said:
I thought about that possibility myself, and with only top bolts holding it they often made buzzing vibe noises.
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License plate is secured

I suppose I'll put some more miles on it and see if it gets worse, better, or stays the same

One of the "tells" is the sound does not manifest itself under hard acceleration, from bottom to the top of the rev range it pulls hard all the way to 60mph without issue, so I'm pondering what kind of mechanical shortcomings such as crank, rods and bearings or would seem fine under heavy load but make strange brief shuddering sounds at other times
 
Removed the exhaust and performed a thorough exam. Everything is solid, not the cause of a rattle.

I'm suspicious that it's a ring issue. There's a bit more smoke even after warmup than I'd like, and the left exhaust port is dribbling a little bit of oil. The right side by comparison is dry, no oil or wetness of any kind. Given no further evidence to consider, it seems prudent to remove this engine for the umpteenth time, remove the head and cylinders and examine those pistons.

I don't know much about broken rings but if a ring broke and stayed in the piston groove, it's possible perhaps to run fine except for a bit more smoke and noise, for awhile anyway, I welcome opinions on this from any of youse
 
You checked to see that the valves were sealing when you had it apart? The valve guides were in good shape? How did the exhaust ports look when/if you had the headers off?

And what about current compression?
 
Do you have access to a boroscope? Were a ring or rings loose in the groove they wouldn’t stay that way and there’d be evidence.
 
What an interesting thread. I’ve just read through it and enjoyed doing so.

Alan :)
 
stl360+450 said:
You checked to see that the valves were sealing when you had it apart? The valve guides were in good shape? How did the exhaust ports look when/if you had the headers off?

And what about current compression?
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You're on to something...coincidentally I sat bolt upright in my chair yesterday with the thought I hadn't performed a compression check yet, so I did

95 psi left side, 135 psi right side, a bit of oil wetness on L side spark plug, R side spark plug completely dry....this is relevant to the oil dribbling from the exhaust port I earlier mentioned

So yeah, I need take a look at the valve seating and look for evidence of leakage through the valve guides but am bereft of knowing how anything in that area could contribute to that intermittent shuddering sound

I'm going to strip this motor out of the frame today and tear it down, at least remove the head and cylinder block, maybe replace the cam chain tensioner assembly (I have extras)

This can't go on, I need to move forward and figure it out one way or the other
 
Hopefully I'll load some pics up soon but here's the lowdown:

1. Cam chain has been grinding the bejeezus off the bottom of the tensioner block...the oil looks like I'm preparing paint for a candy finish
2. Pistons/rings/sleeves look fine
3. Left side exhaust valve stem leak confirmed
4. Con rod big bearings seem ok, no wobble or play

Unsure of next steps, should perhaps pop out the L side exhaust valve and relap. The head is new and I carefully reamed the valve guides properly so I dunno what's going on with the oil weeping there, we'll see. I'm still kind of a novice on some of these things.
 
I would pour some acetone into each intake and exhaust port and check if there are leaks past the valves into the combustion chamber area. Next I would check the ring gap to make sure they are in spec. Lapping too much removes the the thin stellite coating on the valve seating face.
 
boddy said:
I would pour some acetone into each intake and exhaust port and check if there are leaks past the valves into the combustion chamber area. Next I would check the ring gap to make sure they are in spec. Lapping too much removes the the thin stellite coating on the valve seating face.
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These are great suggestions, I will do and report back
 
The left side valve guide leak...I removed the valve and then decided I would replace it with another used valve. I cleaned up the "new" valve and lapped it in. Decided to do a quick leak test I saw on a YT video where a guy filled the top of the combustion chamber with water (covering both valves and spark plug) and simply blew compressed air up the backside of the valve and looked for bubbles. My newly lapped exhaust valve was fine but my intake valve did not perform well. So my low compression on the L cylinder is probably due to the intake valve needing more thorough lapping which I will do now.

Unsure what to do about the valve guide leak, this thing doesn't have valve guide seals, we'll see
 
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