Centrifugal Clutch rebuild

[Gabriel]

I'm doing a very intensive rebuild on my 84 200ES engine. Not the typical top end overhaul. Probably replacing parts still within spec. I just really want this thing RIGHT.

Never been inside the bottom end before. Started pulling the clutch assemblies apart today and detail cleaning everything SPOTLESS. There was about a tablespoon full of thick rubbery crud in the centrifugal oil filter (not the drain screen, duh) and I am getting a whiff of burnt oil so EVERYTHING must come apart for cleaning and inspection.

My question:

The Centrifugal clutch drum is well within spec. About .020 below max ID. There are no rough places or severe damage but there are three scored grooves where the clutch feet have worn into the drum. I'd say about .010-.015 would clean it up.
WOULD YOU set the drum up in the lathe, indicate everything in true and use a boring bar to lightly clean that surface or leave it alone?
As far as getting it right, I have no fear of that. I was a machinist for 13 years. I have a lathe and if I can't do something that simple I need to go jump off a bluff onto some sharp rocks. LOL!
The conundrum for me is, removing material would make the drum perfectly smooth again but also bring me right up to the wear limit.

Resurface or leave it alone? As I say, it's smooth all but for the wear grooves. After some brake cleaner to remove all the oil, a bare finger slides over the surface; Slick.

I have actually done this to a centrifugal go-kart clutch but this is a LOT more precise and powerful machine.
One thing I excel at is over thinking.

Thank you for any thoughts and input.

†††Gabriel†††

[Dirtcrasher]

If you can set it up and cut it properly with enough meat left on it, your doing a good thing...

That "drum" must be hardened to some extent??

[ironchop]

A stock 200ES has about 12hp so it's not like you're going to explode anything easily even if you shaved some material off the drum staying within the factory wear specs.

And I would leave it alone even though Im a machinist as well. Your description of the grooves make them sound irrelevant so I wouldn't touch it




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[Gabriel]

Dirtcrasher is right. A file skated across the thing. Means I would have to use a solid carbide bar and light cuts. Take the chance on chatter ruining it. Wish i still worked in a shop. I'd set it up in the ID/OD grinder with a CBN ID wheel.

[El Camexican]

Whatever made those grooves will probably make them again, so I’d leave it. I gave up on cutting brake discs and drums about 20 years ago. They seem to warp easily afterwards. The more meat the better.

[wonderboy]

TIP: Carefully inspect the pivot holes on the central hub for the centrifugal clutch shoes. The hole where the single chain master link connects can get egged out. It was like that on mine. The result will be that the pivot end of the clutch shoes will be allowed to move outward which will affect the engagement of the clutch and can result in creep at idle or lurch when shifting into gear.

This was something I didn't see when I first put my 200ES back together with a used (e-bay) centrifugal clutch. I got rid of my one-way bearing issues, but introduced this new issue.