Kawi2strokes.com Forum

I pull the cylinders off my H2 every few thousand miles and check the pistons and cylinders.
When I bought the bike I changed the engine case and the top end was fresh. Have 0.5 over
(71.5) Kawasaki pistons but would like to change to Wossners. From what I can find Wossener
pistons would be 71.43, what is the recommended clearance? I'm going to measure the
cylinders today and see if the bores are still usable as is. Who in the So. Cal area is doing
cylinder boring these days? Anyone here on the board recommend someone. I ran Wiesco's
in my H1 and don't they run are larger clearance? What would be the size of a Wiesco
piston for a 71.5 bore? Just trying to see what my options are if the bores are within spec.

Wössner pistons and probably any other decent manufacturer size the pistons for dead-on bore sizes. So for your first over bores, the bores would ideally be 71.500 mm. Of course they can be a little larger and still be fine, subject to possible rattling. Wössner can probably recommend what the allowable bore size or clearance is before a rebore is needed.

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If it surges, that's normal, upshift.

Reading Wossners catalog it shows there H2 pistons are all 0.07mm under the bore size. I didn't think
they ran with that much piston to cylinder clearance Jim?

That's only 2.7 thousandths of an inch.

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If it surges, that's normal, upshift.

Oh your right Jim, I forget the conversion from metric to english.

I measured the left cylinder today, just pulled the head for a quick read. Came out right at 71.5
but with the cylinder still on I could only go to the top of the piston. Bore looked good with some
cross hatch still showing but around the ports it was smooth and shinning. Bike has 150 compression
on a 3 cylinders but I have slight piston rattle mostly on the left cylinder. I'll pulled the cylinders
soon and hone them and see what it reads again. I never have run stock Kawasaki pistons
before this motor and just don't trust them. If the top end wasn't so fresh when I bought it
and pulled it apart I would have gone for the Wossners then. Just checked and Jess bikes
has a sale for $365, great price.

Why on Earth would you not trust Kawasaki pistons? (Pretty strong foundation to the whole triple thing, surely....?)

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"One day, your life will flash before your eyes. Make sure it's worth watching." : anon.

+1

If the cylinders measure OK as you found, and compression is good, I would not hone the cylinders. The rings are sealing well now. Shiny around the ports is normal after it's run for a while.

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If it surges, that's normal, upshift.