Honda Twins banner

1 - 10 of 10 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter #1
I've been driving myself insane on this one. Searching for every possible cause and finding nothing. The only thing I have not done is to remove my cam bearings and check them with a snap gauge. I decided I'd get some video but the noise isn't so bad this time. Before when it would get to clattering it was alarming.

So far I've had the cam cover off looking for filings, I've adjusted all my valves(cold engine), confirmed oil flow to the top end, checked side thrust on the cam which is about .020" ish, removed side cover and cleaned oil spinner and had a poke around. Right now the oil is 10W30 but it was making even more noise with the proper stuff and with the 10W30. There's 10W30 in it because I changed the oil, happened to have 10W30, and I hardly run it until I know what's going on. As you'll be able to tell from the vid, this bike did sit a LONG time. And yes, I know it has CB pipes and handlebars. The poor thing has suffered greatly through it's life. damned if it doesn't run nice though! 1-2 kicks and she lights up!

 

·
Registered
Joined
·
112 Posts
It does sound like it idles well. I rode a CL350 and it made some valve noise like in your video. Here are some ideas:
The source of the aluminum in the oil is a clue to the source of the top-end noise, or it might simply be clutch material.
Sorry to restate what you already know, but just to cover the potential causes:
Valve are set when cold. Intake valve clearance should be .002 in and exhaust .004 in. The left side valves can be adjusted when the timing mark is at "LT" on the compression stroke, with both valves closed. Is it possible you set the valves while the crank was on the exhaust stroke, leading to incorrect valve clearance? The rocker arm pin adjustment pointed outward is the maximum valve clearance, towards the center point is minimum clearance.
Cam chain and sprockets on cam and crank might be worn. If the cam chain tensioner is worn or not automatically adjusting, the cam chain could remove aluminum from the head and cause noise.
Rocker arms could be worn unevenly.

Keep us updated with what you find, so we can help.
 

·
Registered
Joined
·
2,510 Posts
Piston slap?
Does the sound quiet or go away once it's warm?
You've already set your cam chain tensioner?
Unrelated to the noise>>>Your moto oil have the jaso ma endorsement?
 

·
Registered
Joined
·
825 Posts
Cam chain, tension rollers, judging by the blow by in the video probably a rebore and valve job. Cam chain is slowly grinding out the tunnel it runs in. That's where your aluminum in the oil is coming from.

I would say that unless the bike is something special to you that putting 500 to 1000 into it the engine may not be advisable.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #5
Yea, idles nice and runs like a scalded cat! What I did on the valves was roll the engine until there was no tension on the rockers. I'll run through it as you say with the "LT" and "RT" on the respective compression strokes. I adjusted the cam chain and now the cam moves the instant you turn the crank. I figure the adjuster is working.

@doode: Typically it gets louder as it warms up. I'm not sure why but it actually didn't sound terrible this time. Cam chain is set. Right now it's just plain automotive 10W30. It has about 1/10th of a mile on it. It'll be getting the proper stuff very soon. I changed the oil, didn't have the right stuff so I put auto engine oil just so I don't forget and fire it up dry.

@Boomer: Got it for a song from a back yard under an old tarp. Just figured I'd show the blowby. Smells funky, not really like oil. It'll have a pretty easy life with me though. I'll just keep an eye on the oil.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #6 (Edited)
Also, just to be clear, it was clattering before I set the valves. I'm still going to do it by the book, just wanted to get it out there that I didn't make it worse...hopefully!

Here's an earlier vid with the cam cover off. Not sure if the cam ought to have all that side thrust or not.

 

·
Registered
Joined
·
17 Posts
Discussion Starter #7
Ok, I went through it as instructed. They seemed tight so I backed them off until it felt like I think it ought to. Worse...I don't have a ton of practice with feeler gauges though. I'm going to let the engine cool down while I do some other stuff and have another go. It almost looks like the way the rocker sits down in the top spring retaining washer might give you a bit of deception. What I think I'll do is go for a "tight" feeling .002 intake and .004 exhaust. If it got worse going one way, I'll try the other way. Makes sense yea?
 

·
Registered
Joined
·
17 Posts
Discussion Starter #8
Right. I got video but I wanted to let you guys know what's up. I went for the tight feel on the gauges and it sounds like it should. Sort of a shushing sound up top, I imagine from the cam chain and I'd think that's normal. My .002" gauge took kind of a beating. I didn't mash the adjusters down but I was a bit aggressive on them. I wanted it to be tight when I pulled them and I think it worked out. I think I may back them off just a fraction of a blonde...eh, hair, but now I know what's going on with the clatter. So, Scramblr, thanks for pointing me in the right direction! Soon as my vid is uploaded I'll post it here so you can have a listen. Now it sounds proper and takes me back 20 years to my old CB350. My Uncle was into these back in the day and when he was listening he gave it the nod.

Also, since I'm confident in this engine, I took some time and an old aluminum shock housing and made a new throttle grip.

0606181445.jpg
 

·
Premium Member
Joined
·
3,002 Posts
If your 350 Twin DOESN'T sound a little like an old style sewing machine then your valves are probably too tight.

That's just the way these motors are.
 
1 - 10 of 10 Posts
Top