I need to lighten my flywheel on my 1984 TY250S and was wondering if anyone has done this and if so how much did they machine off? I have access to a lathe.

I have, TY350, and recommend it. Makes it more responsive, but also more vibration and pounding with each cylinder firing. May be worse in slippy grip situaitons though. Big diference, not as much overrun when you shut it down say at top of a short bank climb. That's main reason I like it.

Some take off entire ring, I took off about 40%. I would not take off all of it. I think the ring was about 1.5 inches wide, and about 3/8 inch thick. I turned off about 3/8 inch on inner edge, and 3/8 on outer edge. or, you could take off half the outer surface, all across the full width. My thought was I didn't know the effects of thinning out the radial dimension, hoop stresses, etc, so I took off the sides rather than the outer surface.

I can find the exact dimensions, but am headin to TTC tonight for world round. It's not fussy, take off a small amount and see what you think. but personally, I'd not go more than half of it on the 350 at least.

kcj

The first one I took 8 oz off. Which made quite an improvement. Next bike I removed the whole weight, which requires a lot of clutch work and is too much. I`d stay at 8 to 10 oz or about even with the holes pre-drilled in the outside weight.

Thanks a lot for that, i'll take a bit off and see what happens!