KZ650 Starter Clutch

Been having the same problem with my 750 twin. The starter clutch gear for mine is unobtainable. Got a used one from another member and am having it resurfaced.

I've had this same problem since changing to Mobil One T4. The starter gear including drum has been completely replaced but cold it catches and skips. Warm is fine. I think the oil is too syrupy to allow the rollers to bite when cold. I changed to another synthetic and it engages much better. Don't know if it can be considered cured or just improved. Am also interested in Baldy 110's experience with measuring each part. This might be in my future down the road.
Regards,
Art

aek wrote: I've had this same problem since changing to Mobil One T4. The starter gear including drum has been completely replaced but cold it catches and skips. Warm is fine. I think the oil is too syrupy to allow the rollers to bite when cold. I changed to another synthetic and it engages much better. Don't know if it can be considered cured or just improved. Am also interested in Baldy 110's experience with measuring each part. This might be in my future down the road.
Regards,
Art

So I wasn't gonna say anything ....... but this spring I switched to Mobil 4t. For the first 8 starts it slipped so bad I desided to park it. It has never slipped before until then.

I then read that more than a few mentioned this (using Synthetic oil before there problems) so I switched back to Valvoline motorcycle oil and bam ......... From July on 15 starts in a row without a single slip !!! I even pushed it.... almost ran the battery down a few times. On the 16th and last ride of the year it slipped for a second slightly so its right on the edge of needing replacement ...... I'm wondering if its very close to needing repair the extra slipperiness of the synthetic might push it over the edge???

Defently don't want to argue this point!! Many have used Mobil 4T without a problem .... just want to point out what happened in my case also.

Hey Topper this is what I'm finding out also and was thinking about a machine shop work on it. Trouble is with baldy pointing out the larger diameter seems to work best If we have it cut down its defently gonna be .005 to .010 thousands smaller. Hoping you keep us advised on what you did, if it works and maybe what it looks like.

I would hate to dump the new oil. The clutch is normally "locking" the shaft, when the engine starts spinning the centrifugal force retracts the rollers, if the oil makes it slip is because the tolerance is not correct and proper lock can't be achieved.

Now that I'm thinking about it, when I replaced my rollers the clutch got worse, rarely locking. With the new gear I have an improvement but still slips. I'm thinking that my new rollers from z1enterprises are in the small side compared to the OEM.

I just hate to have to do all this again

Nah I'm not really saying to try the oil change cause its was really only a temporary fix anyway. The problem is still there maybe just a little less so?

I know what your saying I only want to do this once too ...hoping we can get lucky will keep watching for clues.

It's not the oil, the oil is bringing the problem to your attention, the problem will eventually rear it's ugly head with conventional oil. Fix the problem not the symptom.

Interesting thread, had issues myself here but not sure the answer.

I notice the surface finish on the new part is seemingly purposely machined rough with the concentric machining marks visible. This seems by design, kawasaki would never manaufacture something so rough by accident.

Conversely, the rollers are really smooth like a crank journal.

Not sure this is new problem, was talking about this to my local bike shop awhile ago, even in the 80's they were changing these in-frame.

The rollers have to be smooth so they can slide in the clutch, the gear has to be rough so the rollers can bite on it.

I just ordered OEM rollers pins and springs instead of the Z1Enterprises ones. With the OEM part and the OEM gear I just installed I assume the issue will be corrected. Unfortunately I will not be able to work on this until January.

murquiza wrote: Unfortunately I will not be able to work on this until January.

)o: Bummmmmmmmmer.
Keep us posted if things change and you get a wild hair up... well, you know. :whistle:

Has anyone tried to machine the old sproket surface ?

If you decide to have the boss machined down to a smaller diameter and then slip a sleeve over it be very careful about the diameter of the sleeve. Take a look at the link below; it shows what can happen if the sleeve is not exactly the right diameter. Ed

www.kzrider.com/forum/2-engine/593938-a-...ists?start=20#633554