Topic: How Much Cam Chain Noise is Normal?

[Bob Wessner]

Going through all the steps leading up to carb syncing (timing, valve adjustment, cam chain tensioning) I adjusted the cam chain per the manual, even stuck something in the hole to "help" it along. I have to say, I noticed no movement whatsoever while doing it, not sure if that's sometimes to be expected or what. There's 15K on the engine (750 K0). Anyway, it's running pretty well, an intermitant miss from #3 during warm-up, but once warmed-up rarely or barely happens. The real question is just how much cam chain noise is normal. Seems like mine is still noisier than I remember, but it has been a few years. Would it be worth pulling the tension unit to see if it is moving freely?

[MRieck]

I'm sure the rod is free...especially with a little help from pushing. You set that static method from the book yes? As a side note I installed the M3 Racing tensioner...100% quieter- no #$%*. Just the tapping from the rockers now. Sorry Bob, didn't mean to steal the thunder.

[Bob Wessner]

MRieck,

Is there a method other than static??

[Jonesy]

Some guys like to do it while the bike is idling.. I'm not one of them!

[Bob Wessner]

Don't know if it would influence the answer on checking the tension unit or not, but the bike was in storage for 22 years! It's now been through 2 oil changes and the first was pretty damn dirty to say the least.. fine now though.

[Jonesy]

I've heard that the spring inside the tensioner can weaken over time, between being held in the compressed position for so long and the heating/cooling cycles it sees from normal operation.

When you tensioned the chain, did you do it just past the TDC on the compression stroke on cylinder #1? Honda modified the directions in later years. The pointer for the ignition timing should be lined up with the spring pin on the advancer. This way the chain is being tensioned at the best point of slack:

[chundy]

I just adjusted my CCT, on my 77 750.  I have always had a some noise from mine.  I just rebuilt the top end and and had my CCT out.  The spring is old but has some serious spring so I wasn't worried.  As per the manual I started the bike, let it idle as I adjusted the tension.  By adjusting the tension I mean let the bolt loose for 10 seconds and then tightend it up.  Seems to be OK now, however when it's cold it still make a little noise, once she's warm things sound nice.  Give it a try while the engine is running, as far I can tell, and as per the manual it cannot do any damage.

[Clyde]

Bob,
It might be worth pulling the tensioner out and making sure that there are no marks/burrs on the rod to stop it working. I have a couple that were badly marked and would not slide correctly. One I had was badly indented and it kept on returning to tha same spot when you tightened it up again

[rob]

Hi everyone,

I am in the same position as Bob.. namely, how much noise is too much.

I have an 81 CB650 Custom, and the instructions in the clymer manual say to take off the point cover, losten the cam tensioner nut, then re-tighten it as you rotate the crank shaft using a wrench 4-5 times.  I have done this, no improvement.

What confuses me, is all this talk of the lock-nut?  My Clymer mentions no such lock nut, all I have got is the one hex nut behind the cylinders near where the idle adjustment screw is.  Is this lock-nut only for specific CB's?

Thanks,

Rob

[MRieck]

Some guys like to do it while the bike is idling.. I'm not one of them!

Me too.

[Bob Wessner]

Trying to retention while running never seemed logical to me, seems the chain would be thrashing about a bit, but what do I know.

[Lumbee]

...just an FYI, don't confuse Cam Chain noise with clutch ring noise.  I went nutz the first month I had my 750 thinking it was cam noise till I finally got my ear down by the clutch cover and realized it was clutch rings...

[Bob Wessner]

Hmm, sure sounds like chain noise, but since it did to you as well, I will double check that, maybe try the hose listening trick I read in another post somewhere to try and isolate it.

[Jonesy]

You can also touch a screwdriver against the case and hold the rounded end of the handle against your ear (old mechanic's trick)

A word of caution when using hose as a stethescope: Try to use clear hose as the black stuff is somewhat conductive (from the carbon put in the rubber) and if you get too close to a leaky sparkplug wire you can get a nasty jolt to your ear! Be careful...

[TwoTired]

You can also touch a screwdriver against the case and hold the rounded end of the handle against your ear (old mechanic's trick)

A word of caution when using hose as a stethescope: Try to use clear hose as the black stuff is somewhat conductive (from the carbon put in the rubber) and if you get too close to a leaky sparkplug wire you can get a nasty jolt to your ear! Be careful...

Yes, the screwdriver thing works quite well for conducted mechanical noise.  But, it won't help much for finding suction leaks.  I never thought much about carbon in rubber making it conductive.  That's a good thing for tires,  As it could bleed off static, but hoses?  Ignition leads are black and not usually conductive.  If the insulation is in reasonably good condition you can grab right on to it with out a problem.  So, there's more than one way to make things black.   No matter, I usually use clear aquarium tubing, anyway.  The stiffer walls of this tubing bounce the sound better than soft rubber, latex, or silicone tubing.

Cheers,

[kghost]

Twotired,

Congrats on using Rubber, Latex, and Silicone all in the same post.

Didn't even make it dirty or about Terry.

[Jonesy]

I never thought much about carbon in rubber making it conductive. That's a good thing for tires, As it could bleed off static, but hoses? Ignition leads are black and not usually conductive. If the insulation is in reasonably good condition you can grab right on to it with out a problem. So, there's more than one way to make things black. No matter, I usually use clear aquarium tubing, anyway. The stiffer walls of this tubing bounce the sound better than soft rubber, latex, or silicone tubing.

I've never had it happen to me, but I read it in Popular Mechanics years ago in an article about finding noises, etc. in cars and it makes sense. Carbon black is put into rubber to make it more durable (without it tires would wear down like a pencil eraser after a few miles) and it also absorbs UV light, which degrades rubber. True, the ignition wires have to be in REALLY bad shape and so many other variables come into play, but they probably didn't want to get blamed for the one freak accident that could occur. (And I'd hate to have it happen to some poor guy we're trying to help out because I didn't say something!)

[TwoTired]

Twotired,

Congrats on using Rubber, Latex, and Silicone all in the same post.

Didn't even make it dirty or about Terry.

Tears in eyes. LOL

It's amazing how a different point of view can change the context.   

[Mikeshonda750F]

It is also true they conduct electricity. Years ago in shop class we were learning the fundamentals of the secondary ignition system and our instructor took the black rubber hose off of the windshield pump and nozzles, replaced a plug wire with it and started er up.

[dpen]

Another way to tension the cam chain quickly is to have a friend (if you have none your wife will do) apply pressure to the kickstart.
Don't actually depress the pedal, just take up the slack & hold a slight pressure on it. Now play with the tensioner.
This position ensures that the chain is pulled tight at the front of the engine.
This is an automotive practice & is actually the recommended way for many makes including Mazda (naturally they use the harmonic balancer as cars don't have a kick start).
I use this way & the only disadvantage is that the quiet chain makes the clutch rattle seem worse.
Dave

[Bob Wessner]

Just as a follow-up on my original post about cam chain noise. What I found was that when out of the garage and riding (first ride today) it didn't seem excessively noisy at all. I'm guessing the adjustment worked fine and the noise I was hearing, which seemed like a lot in the garage was because it was bouncing off the walls or something. May take a look at the adjuster down the road the next time all the interfering parts down there are off the bike.

[lordmartin]

And as for clutch noise you can soon tell if its that as 90% of the noise will go away  when you pull the clutch lever in. I about had a heart attack on starting my bike up after doing the engine (it was a trashed non runner when I  got it) putting new rings on etc.etc.  I thought I'd wasted my time doing all that work.
 I thought the bottom end was going out till I found out its just the jangley clutch dance at idle!   My cam chain noise is ok, just the odd rustle and tinkle.