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I have a 1993 907 with 45,000 miles. I had the valves adjusted, new belts, a broken valve spring replaced (it was the spring that takes out the slack in the valve train) this March. But I have a rattling noise in the engine at hight rpm. I not sure if it is just the clutch, but it doesn't sound like it. So, I have a theory and I wanted to test it on everyone.

Background:
The starter engages a couple of gears that turns the gear that has the shoulder on it that engages the starter clutch on the back of the flywheel. It's a bendix type clutch, with knuckles that engage when the starter turns the gear and the gear turns againist the knuckles, which engages and turns the flywheel and the crank and starts the engine. Now, when the engine gets going faster than the starter and gears rotating speed, the starter clutch dis-engages. I am wondering if there is a problem with the starter clutch and it locks or freezes on the gear, can that make the gears and the starter keep turning while the engine is running? And at high RPM's could this be the rattling going on?
I can hear this rattling when I change gears and I pull the clutch in slowly and there is a brief time when the engine spins free before I let the clutch out in a new gear, and when I am deaccelarating from High rpm, like being in 2nd gear from high rpm and letting go of the throttle and letting the engine do the braking, I can feel and hear this rattling. It is very similar to the clutch rattling. My clutch (OEM part) is about a year old, the original clutch basket is still on, and I did notice during my winter checking that the tabs on the clutch plates showed signs of wear, indentation on the tabs. But this rattling sounds alot like something spinning faster than it should and rattling when it starts to slow down.
Thoughts and questions?
Thanks,
du907

I don't know what it is but I highly doubt it's the starter staying engaged. A started that remained engaged would be spinning about ten times it's design speed at high engine rpm and wouldn't last very long...

On bevel Ducs a rattling on decel can indicate the big end is on it's way out, but the Paso doesn't use roller bearings on the rods so I wouldn't think that would be it???

Flywheel Nut maybe??

Has the engine been apart recently at all?

No, the engine has never been torn all the way down. I have put in new pistons and rings, base and head gaskets with o rings. I had to put in a new starter clutch back when it was new, at about 4,000 miles, I have about 45,000 miles on it now.
Thanks for your comments
du907

It was the clutch afterall. I removed it and rev'd the motor sitting still and no noise. The basket is quite worn and I believe the clutch plates with the friction material on them are alumn. This would explain why the tabs have such deep grooves where they contact the clutch basket. What should I replace the parts with? Steel OEM basket and steel plates, or alumn basket and alumn. clutch plates?
du907