valve adjustment woes...

ok so recently I've noticed a bit of "noise" emitting from the top end of my engine... not ticking just "mechanical" noise... so I'm thinking it's time for a valve adjustment. pull the cover and start checking clearances. all valves on the exhaust cam are at .003... number 2 on the intake cam is at .003 also but the other 3 on the intake cam are so close I can't even fit the thinnest guage I have in there... almost zero clearance. is this my noise creator? and what would cause those 3 valves only to be out of spec?

78 kz650 B btw

No, valves that are too tight are quieter than valves that are too loose.

I suggest that while you have it open inspect the cam chain guides and rollers. Then adjust your cam chain.


"what would cause those 3 valves only to be out of spec?"

These types of valve trains do get tighter with wear.

KZCSI

ok will do... I was told to simply loosen the locknut then the bolt and then retighten. but then I was told the engine has to be rotated to a certain spot first or the chain won't be adjusted correctly. is this true?

its true, its has to be rotated to the first corner on the timing plate down where your ignition is. go two complete revolutions, then go past all the timing marks on the 1,4 side, until the corner is lined up with the pointer. then loosen the locknut and re-tighten. if its quiet and you release it quickly enough, sometimes you'll hear a click, but not all the time.

thank you for the info!

I was wondering... if the valvetrain is designed to get "tighter with wear" how do the valves get noisey when they near needing adjustment? what causes the noise?

Noise isn't the valves. They don't get noisy with age and miles. Noise is either cam tensioner problems or the idler sprockets or exhauast leaks. Exhaust leaks are probably the #1 valve noise.

tomorrow I'm going to adjust my camchain properly and see if the noise is still there... hopefully it isnt.

I don't think having some mechanical noises on these bikes is uncommon. They are using mechanical lifters so there will be some noise. Verses hydraulic lifters that will have very little noise.

RonKZ650 wrote:

Noise isn't the valves. They don't get noisy with age and miles. Noise is either cam tensioner problems or the idler sprockets or exhauast leaks. Exhaust leaks are probably the #1 valve noise.

Kingcobra...this is good advise. A note about automatic cam chain tensioners...they fail. My bike had a lot of top-end noise too. No amount of maintenance could get it to work correctly, so I purchased a new MANUAL type adjuster from Z-1. Now I adjust it about once a year and the noise has gone away.
The advise about your valve clearences is also correct. I just did my valve lash adjustment and 5 of 8 valves were tighter than spec...just like everyone says will happen. I know it sounds counter-intuitive but the valve clearences will get tighter over time, rather than looser as you would find on a rocker-arm style valvetrain. I suggest buying a manual tensioner and reading up on how to perform a valve lash adjustment on underbucket shims.
BTW...you should add your bike and location info to your signature line. Then everyone will know what you have and can answer your questions accordingly.

Just about all valve adj will get tighter overtime,, the valve wears into the seat and the seat wears deeper in the head, thus a longer valve at the other end and tighter. this is a normal and good thing, ifthe ywent the other way I would be worried that something is going wrong with the cam or lifter bucket.

another thing that can cause a noise is the carbs being out of sync, it changes the cyl pressure and causes the cam chain to "rattle" so you may want to check that also