I thought unobtanium would be shinier

My problem didn't show up till I changed to Mobil 4T synthetic........ slipped 8 cold starts in a row..... then after reading another member's slipped too after going with syn oil I switched to Valvoline 10/40 bike oil and it went away for most of the rest of the year till it cooled off to 60 or so and the extra drag caused it to slip again.

So I think mine was just at the limit of needing fixing and the extra slippery ness of the syn caused it to show up? I will be using reg Valvoline bike oil from now on though........ ED650 uses Mobil 4T and he starts his all winter and is not having a problem so who knows?

Mine starts so quick (instantly) when warn so that was never a problem except when cold. Good luck I have mine all buttoned up with new parts but won't be getting the motor back in till this fall so I have my fingers crossed....... I did find a lot of notching and 2 weak springs and one a little worse yet...... guessing the only way to bench test it would be to hot wire the starter and try it that way.

I may be the one kZB2 650 is referring to. My starter slipped after changing to Mobil 4T even though all the component starter parts were new. I changed to another synthetic and the clutch problems stopped immediately. It still operates correctly after about 7000 miles. The old parts look very good except for some light notching on the contact surface of the sprocket gear. I intend to have it ground by a good machinist and reusing it along with the rest of the parts somewhere down the road. I really had hoped to use the Mobil 4T but it just didn't work out for me. I know many of you don't think synthetic is necessary in these motors but I do distance riding and on a 100 degree day with a loaded bike it seems to me to be a good thing to be using.
Regards,
Art

Surprisingly, the ones that were slightly notchy worked fine, but the nicely smooth polished one that had been slipping looked the best, Using verniers and a mic on the gear boss and rollers I can't see any dimensional change.

I'm experimenting with a test rig, using a 20 kgM tourque wrench to try to cause slippage. Preliminary tests the defective clutch was locked on, even with one roller removed - although it jammed up and didn't easily disconnect. This will be a two man job to get to 140 ft/lbs, one to hold it and another to turn it.

What tourque figure I need to asses this is a problem... trying to put a Nm figure here I think would be some calculus with a definite integration on the compression stroke between between lobe centre and TDC. Even simplified to an isothermal system it is beyond my simple mind right now.

Easier might be a cold cranking test using a clamp ammeter and voltmeter, Power = Volts x Amps, That gives starter motor power that I' can't find a figure for. Power = Omega (angular velocity) x Tourque rearranging that with a known cranking speed hopefully will give me the tourque.

Anyone got any idea what the cranking tourque would be on this?

I'm afraid it's a flawed design that Kawasaki tried to work around with no positive results. Being it effects a wide range of models and years, my question is, why did they stay with this design? Do the newer models still have it and what changes were made to prevent the problem?
Steve

Evidently, the 2016 KLX110L uses the same system. Perhaps it has been improved, perhaps not.

When Kawasaki designed the all-new 900 Ninja, it included a new chain drive starter. All of the many models tha have used descendants of that engine, including 1000, 1100, 1200, Ninjas; second generation GPz 1100, first generation Concours, and the ZRX, use it, too. It works pretty well until it doesnt. When it goes wrong, it is known to be a destroyer of clutch baskets and other expensive bits.

OMG! :ohmy:

Being it effects a wide range of models and years, my question is, why did they stay with this design?

I guess using a primary shaft keeps the engine slim, as opposed to the earlier kz900 variants.

Although it is a known fault, and probably more common as these bikes age, it seems generally quite reliable. The despatch rider's favourite used to be the Kawasaki 550 shaft drive, the City of London virtually ran on Kawasaki 550's and Honda CX500. These GT550 shaft drives would often clock 100k miles and had a good reputation for reliability even when despatched and abused...also the 550's have no kick starter.