Hey all, I have a 1982 KZ750 LTD 4 cylinder. I have this clunking type noise (can't seem to pinpoint it) from the engine, even with mechanics a stethoscope. Most dominant in idle...or under 2000 rpm's. It is there in first gear as well until I reach 2000 rpm. Sounds like a diesel engine until around 2000 rpms clunk clunk clunk. The noise will disappear if the clutch is let out about a 1/4 to 3/4 as well but will return in gear under 2000 rpms. This sound has been present since i've owned the bike (around 500 miles).
A little lag around 7000 rpm (probably carb I'm guessing)

Bike stays in gear
shifts fine, a little clunky depending on rpm
doesn't smoke
power seems there although a more thorough carb cleaning could be used (I just did a quick clean of jets, bowls, etc)
29K miles
coils are firing all cylinders
on centerstand in nuetral the rear tire will spin slowly

I'd take a look inside but I'll have to probably easy-out some of the SCREWS used to hold some of the covers in place. I had to check the alternator and 2 of the 4 screw heads stripped out and broke.The bike had set obvisouly in rain/snow for awhile judging by all the rust I cleaned of it. A few electrical fixes later, carb cleaning, new tire, new oil, gas, lube, etc. and I was down the road.

I like the bike, it's a work commuter for me and I'd rather keep it than trash it/part out it. Any ideas or suggestions, anyone had or heard of similiar problem?

Thanks

Charles

 

Sounds like the valve train, or maybe the cam timing is out. I had a similar problem ended up being a bad rocker arm, and valve. Sounded like a Cummins diesel.

 

need for a valve adjustment will sound like that if it is let go for too long.

 

Thanks, I just read through the manual. Ewww. Looks like alot of fun doing a valve adjustment.

 

Try the cam chain adjustment, although I am not familiar with the KZ models.

 

Don't worry about doing a valve clearance job, that isn't the problem.

Without a doubt your cam chain tensioner is shot. I had the same problem with my KZ750. The factory tensioners have an extremely high failure rate, and were even recalled back in the day. Without enough tension on your cam chain, that chain will just slap around making the nasty noises you hear. this also causes some major timing problems especially when jumping from high to low RPM's. Do yourself a favor and buy a manual cam chain adjuster. You'll never have to worry about a slacking cam chain again.



With a manual cam tensioner, you will have to adjust it occasionally, i.e. every valve service.(6000 miles) But, it only takes a minute to make the adjustment.

 

Nice pic mark

 

Thanks.

 

Yea, I'm going to try the manual cam chain adjuster before getting into the internals. I saw a couple on ebay for a little over 50 bucks. I'll post with results after installation and adjustment.
Thanks for the help.

Charles

 

Don't forget the gasket!

Here is a link to the manufacturer's site: http://kzzone.com/sprockets.html