Loud Rattling Coming from gearbox

daveo wrote: A couple years ago the three starter-clutch mounting bolts became loose on my engine. Whether that caused magnet breakage on the engine rotor (or the opposite), I don't know. But that is what happened in my case.

Before discovering the culprit, I thought sure something was loose behind the transmission cover.

Somehow my attention arrived at the generator cover. When lightly placing my hand on the cover, I literally felt something wasn't right behind it, with engine idling and the bike on the center-stand. If you try this, do it while the motor is warming up, because that cover becomes very-hot.

This may not be the problem you are having, but it could be.
Good luck...

Good call Daveo, considering that I'm having the same problem currently I don't know why I didn't mention this. My problem was slightly different though where the aluminium part was actually loose on the steel boss that goes onto the crank taper. I could actually rock the outer rotor while mounted tight on the shaft.

Bozo wrote:
Good call Daveo, considering that I'm having the same problem currently I don't know why I didn't mention this. My problem was slightly different though where the aluminium part was actually loose on the steel boss that goes onto the crank taper. I could actually rock the outer rotor while mounted tight on the shaft.

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Ouch... :ohmy:
I wound up with an Electrex RO3-02 rotor (replacement for the RO3 on-which the magnet separated, covered by the 1 year Electrex warranty). It didn't fit correctly on the engine without having to shorten the starter-clutch gear (hub length) to allow the rotor/crank tapers to snug up, and not bind the starter-clutch mechanism against the engine case while tightening the rotor bolt. That was a major pain in the azz (way-worse than explaining it), but it works really well now. The RO3 rotor has a one-piece machined housing and continuous magnetic strip, is precision balanced...and the engine now seems-so too.
Hope this helps...

daveo wrote: Bozo wrote:
Good call Daveo, considering that I'm having the same problem currently I don't know why I didn't mention this. My problem was slightly different though where the aluminium part was actually loose on the steel boss that goes onto the crank taper. I could actually rock the outer rotor while mounted tight on the shaft.

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Ouch... :ohmy:
I wound up with an Electrex RO3-02 rotor (replacement for the RO3 on-which the magnet separated, covered by the 1 year Electrex warranty). It didn't fit correctly on the engine without having to shorten the starter-clutch gear (hub length) to allow the rotor/crank tapers to snug up, and not bind the starter-clutch mechanism against the engine case while tightening the rotor bolt. That was a major pain in the azz (way-worse than explaining it), but it works really well now. The RO3 rotor has a one-piece machined housing and continuous magnetic strip, is precision balanced...and the engine now seems-so too.
Hope this helps...

Attachment IMG_7264.jpg not found

Daveo, I've seen the same type of rotor for my Z1R and I contemplated buying one. My current rotor has some scoring on the taper (spun on taper), because of that my rotor does not go in far enough causing a bit of slop on the starter gear (can be rocked slightly sideways).
Once you got your rotor to work, was there any other difference to standard?? i.e heavier, less power??

Bozo wrote:
Once you got your rotor to work, was there any other difference to standard?? i.e heavier, less power??
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I don't know...neither heavier (weight) or less power, but a much-smoother engine.
If you are considering the purchase of an Electrex RO3 rotor, inquire specifically about the RO3-02 (pictured above). . You will need to shorten the rotor bolt length by .5" or so, to compensate for hub/crank variation.

Bozo wrote:

daveo wrote: Bozo wrote:
Good call Daveo, considering that I'm having the same problem currently I don't know why I didn't mention this. My problem was slightly different though where the aluminium part was actually loose on the steel boss that goes onto the crank taper. I could actually rock the outer rotor while mounted tight on the shaft.

_________________________________________________________________________

Ouch... :ohmy:
I wound up with an Electrex RO3-02 rotor (replacement for the RO3 on-which the magnet separated, covered by the 1 year Electrex warranty). It didn't fit correctly on the engine without having to shorten the starter-clutch gear (hub length) to allow the rotor/crank tapers to snug up, and not bind the starter-clutch mechanism against the engine case while tightening the rotor bolt. That was a major pain in the azz (way-worse than explaining it), but it works really well now. The RO3 rotor has a one-piece machined housing and continuous magnetic strip, is precision balanced...and the engine now seems-so too.
Hope this helps...

Attachment IMG_7264.jpg not found

Daveo, I've seen the same type of rotor for my Z1R and I contemplated buying one. My current rotor has some scoring on the taper (spun on taper), because of that my rotor does not go in far enough causing a bit of slop on the starter gear (can be rocked slightly sideways).
Once you got your rotor to work, was there any other difference to standard?? i.e heavier, less power??

Bozo I have noticed that my starter gear does the same. I think this may be the source of the rattle and be causing the magnets to crack. The previous owner told me that he replaced the rotor before selling it to me so if it cracked again so soon there's definitely something else wrong. did you manage to sort a solution to stop it rocking?
I tried to sync the carbs but one refuses to match the other 3. However no matter the sync status, the rattle persists unchanged.

Apologies for the thread revival but after moving house, braking my rear suspension trying to tighten the rotor bolt (don't ask), finding a shagged air mixture screw and having to replace a carb body, replacing the starter motor, and fixing the fuel tank, I'm finally able to revisit this. Truth be told I actually forgot I posted here and only realised today when I went looking for a solution to my rattle (again!!). This in combination with a heap of other problems is making me resentful of this bike

Choose original Genuine Kawasaki parts, whenever possible. After both aftermarket rotors failed, I'm back with what works.

Thanks Daveo, I currently don't want to replace anything though until I know the rattling's sorted... Is the starter gear supposed to have any freedom to tilt?

Chris_Z1100 wrote: Thanks Daveo, I currently don't want to replace anything though until I know the rattling's sorted... Is the starter gear supposed to have any freedom to tilt?

A pic might help, but when the generator cover is removed you may be able to move the support pin (and gear) side to side a little, since the exposed end of the pin is no-longer aligned by the cover.

Sorry wrong gear, I'm talking about the starter clutch gear, just behind rotor.

can't get the photo to attach for some reason....

The starter "clutch" gear is supposed to be loose enough to spin freely, but with a slight amount of friction felt while rotating it.
I recall having the ability to rock the gear off axis slightly, with the correct thickness rubber spacer installed behind the gear, since it does fit somewhat loosely on the bearing on the crank. :side:
IMO that would not cause the type of rattle noise you mentioned, but do seek additional opinions about that.

Well if that's not it, I'm back to square one here then
Maybe I'll take the bike in somewhere to get synced professionally. If the rattle's still there I'll start pulling more things off... I've got to do a rebuild at some point to try and stem some of the oil leaks...

Chris_Z1100 wrote: Well if that's not it, I'm back to square one here then
Maybe I'll take the bike in somewhere to get synced professionally. If the rattle's still there I'll start pulling more things off... I've got to do a rebuild at some point to try and stem some of the oil leaks...

It's all a very worthwhile learning process. Do it yourself and put the money saved into a Morgan Carb Synchronizer, to enjoy using over and over...