Piston Ring question?

OK, I got to ask what measurement tools are you using? It is a real Touch to get accurate in this small dimension. Do you have a .001" of an Inch and a .002" of an Inch feeler gauge? Try fitting those under the ring/ land.
What I am thinking is if you did have .03mm or less that the rings would not be very "Free" when rotated.
Try some feeler gauges, you can use mm if thats your your tool set, or inches as long as you check it this way.

andy9802gt wrote:

calvin17d wrote:

so the ring end gap spec in my manual is listed as standard =.3mm and wear limit = .7. I am at .4ish.

Also the ring/land spec is .06 as standard with a wear limit of .18. my measurement is tighter than spec at .03mm likely due to a bit of carbon.

piston will slide into bore with rings installed.

If the standard is .06 and you have a measured .03 you're already tight. If the new rings are .03 thicker than the old looks like you ended up about .06 tighter than the standard= no move-y in the groove-y.:ohmy:

Your math is off a little

groove = 1.51 mm
ring = 1.48
clearance = .03

edit*
apologies, your math was right, my intial measure on the old ring was .03. I am beginning to think that my landing is tight? This seems odd. I have scraped but perhaps they need a soaking.

Spec groove = 1.51
spec ring = 1.45
Spec clearance = .06mm

Motor Head wrote:

OK, I got to ask what measurement tools are you using? It is a real Touch to get accurate in this small dimension. Do you have a .001" of an Inch and a .002" of an Inch feeler gauge? Try fitting those under the ring/ land.

Yes I have down to .0015" and this is as small i can fit in with the (((old)))) ring.

New ring will not accept this but does move in groove with minimal complications.

I am wondering why that bike has a smaller tolerance? Is it air cooled as well? Do these tolerances consider operating temperatures. I am beginning to think that I may take a gamble that my tolerance may be safe.

Got to say that it must be real close to the min spec. One more thing to try, some of these guys have homemade soda blasters to blast clean parts. Do you have compressed air and such?
Holding the piston with rings installed in a solvent solution, then spinning the rings around the groove will wash out some more carbon maybe?
Also did you try the old ring, broken to clean? No sign of carbon? Post a picture.
Can't say the last time I had NPR rings but the larger thickness is a small concern, I wonder why they did that. I've been getting OEM Kawasaki rings and pistons for the KZ's I've fixed up. Sometimes its worth it to pay the extra, if there available.