alright, i have a 1980 kz650 f1.

the timing chain sounds horrid and upon further inspection i need to do some shim work.

this bike was raced and built for it. it has a high lift cam(i am pretty sure as there is only about .025" between the case and the cam lobe peak) supposed to have ti valves and bored to 720cc. it has a v&h 4:1 and pods. i am not sure if she is running high comp pistons, but i can tell you that she likes 91 octane way more than 87.

i have a few questions that i am hoping that you can answer.

first, is there a way to measure the timing chain and related components while they are still in the bike to see if they are still good? i think that if i get a manual adjuster it will still work, the sprockets up top looks fine although the idler bearings seem a bit loose.

it there only one chain guide in this engine? i didn't see one towards the front.

how would one replace the sprocket on the crank shaft if need be? is there a common problem with them wearing out?

how well does the dyna 2000 electronic ignitions work on this bike?
Dyna 2000 Electronic Ignition & Coils DDK2-2C KZ650 KZ750 DDK2-2C - from Z1 Enterprises, Inc.

is the accelerator pump worth having? i know when i slam the throttle open she doesn't really seem to hesitate.

 

took a quick measurement of my cam, the intake seems to be a .410 lift.

there are chips out of the back side of the lobe, what causes this?

 

A lot of good questions turtlemann, but first of all, you have a nice looking ride!

Supposedly on the cam chain wear inspections, 5kg of force for 20 links for a 127mm length measurement. That just checks to see how far the chain has stretched. The service limit is almost 129mm. 20 links is a lot to see while still in the engine. So halving the numbers makes it possible. (these specs are from my KZ1000)

I hit up a fiche concerning the cam chain wear guide and rollers. You are correct on the one wear guide. Kawasaki Motorcycle Parts 1980 KZ650-F1 CAMSHAFTS-CHAIN-TENSIONER Diagram

I have seen some play with the idler gears before, but you can tell by the heat dis-coloration and of the excessive play concerning the bad ones.

How many miles on the rebuild/engine work?

There were some pitting issues with many of the japanese bike cams in that era. Kawi and Honda from what I have seen. Not sure on chips though on the heel of the cam. You could check the valve spring pressures while you are inside of the engine easy enough.

I looked at the fiche and it looks like the cam chain gear on the crankshaft is non-replaceable.

Congrats on the ride.

 

so what is there to be done about the cam pitting? i don't know of anyshops around her that could hard-band it and regrind it.
seems as if it is wearing out the bucket on the worst lobe. cyl#1 intake

where is the best place to find the required spring rates?

so this bike doesn't really have guides, just rollers(seems like that would free up a little power but why did they move away from them?)


and thank ya, i just hope that i can keep her running.

 

post up some pics

 

and yes, my oil looks pretty nasty

you can see where it has worn though the case hardening on the worst lobe there, but i want to know what started the pits in the first place as there are a few that have them, but they don't look worn.

 

wow, chips was an understatement. That there is "chunks" To what may have caused the issue? oil, spring/cam/bucket issues? Tough call, but you made me cringe on the pics. The journals ok? Maybe that loose idler caused some havoc that you mentioned? (the one pic shows scuffing along the entire cam lobe) The rear guide does chunk out, but would not think that would be an issue on the cam. But who knows. You are the teacher on this one.

 

do you think that if the chain was loose that it could click over and cause the cam to jump?
but the valve is what causes it to spring forward after it gets to the peek of the lobe.

i guess good journals would pretty much rule out oil wouldn't it?

the only thing i think this could be is if it where jumping off the point with valve float, but that should be farther down the ramp shouldn't it, or not be there at all since it is so close to the point(aka not enough hammering force).

 

yeah, that was where I was thinking on along with all of the other components in relation to the cam issue.

Which was another possible aspect. Valve Float at high rpm racing as this was a racing engine before you bought it. A lack of spring pressure, not pulling the valves closed, places the toe of the cam at a continuous pounding of the valve at rpm valve Float.

Here are my thoughts: WEB Cams, new valve springs and rebuild the head or freshen up and check tolerances. Have you checked out KZriders forum yet? I am not pushing you off, but better results can be had with multiple sources of information. So don't run off on us here at KF if you find a result elsewhere and let us know of the outcome.

 

Clearly new cams and either shims or buckets (if shim under bucket) are in order if nothing else.

When it comes to the cam drive I will tell you based both on my own experience with two Kaws and the experience of a few hundred others, the OEM cam chain tensioners just plain are junk. Due to my own bikes having tensioners go bad and not having a source I ended up doing them and have a good reputation for them on a number of forums including this one. I just sent a tensioner out for a KZ650 yesterday. PM me if you decide it is of interest along the way.

I wish I could help you with the cam thing. All I can say is you may be able to get a good used set by looking up a salvage shop. I know of one in Dover Ohio, about 60 miles from Steubenville. It is Lehman's Big Open Road. Owen has a pretty good handle on Kawasakis, having built and drag raced them, is a trained Honda tech, and bought up a few semi loads of 70s-80s Japanese bikes and has been breaking them down. He may have cams that will work or maybe even an entire engine. Look him up on the internet and give them a call. Good people and probably good prices. Tell them Krieger referred you to them. Don't know if it will help, but I know and have worked with some of the guys there as well as Owen.