Flywheel/collet spinning

[Ian Inverarity]

Hey guys,

I had a bit of a funny problem with my K-90 at the Nats recently. The flywheel collet had been spinning on the shaft and grinding against the front bearing. This cause the engine to ingest a surprising amount of brass and ruined the bearings. There was evidence that the flywheel had been spinning on the collet as well.

Funny thing was I had no problems with starting it (ie the flywheel didn't spin loosely when I was starting the motor) and I never lost drive from it. When I went to pull it apart I found the damage, but everything was still tight and I still needed my small gear puller to get the flywheel off.

With this setup there is no way the step on the square drive can bottom out against the collet, there would be at least 4mm clearance. Also the shaft from the K-90 doesn't protrude far enough into the square drive to bottom out. The square drive was tight to install, but I was reasonably certain I had it tight enough.

I have run a tap through the square drive and it screws on easily now. I have loctited it on and done it up even tighter now. But I dont want this problem to occur again. Has anyone ever had this, or have any ideas what may have caused it? ???

Ian.

 

[Hammerhead]

Is there any possibility that it was loose when you started it, and it tightened itself? K90! You are charged with covering up the evidence.

Sounds like a good one for Sherlock Holmes. ;D

Hammer

 

[Ian Inverarity]

Hammer,

I didnt notice anything when I started it. My motor was slow for the last few days and almost stopped in my last race. Having seen how much brass was in it, I am amazed it ran at all! But I have never seen anything like this before, really weird! ???

Ian.

 

[Twin_k90]

the only thing i can think of is the collett loosened then tightend up, i had to tap mine out a bit more so they screwed on a bit further,