matching piston sizes used on different machines - Kawasaki Motorcycle Forums
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post #1 of 2 (permalink) Old 03-05-2017, 07:16 AM Thread Starter
79 ke250
Join Date: Mar 2017
Location: Sackville Nova Scotia Canada
Posts: 7
matching piston sizes used on different machines

Hi everyone I'M a new member and this is my first post. I have a 79 KE 250 and I have discovered that the piston and rings have been discontinued for many years. I was lucky enough to track down a NOS set of rings for the Ole girl. A piston however seems to be next to impossible. So in research I have discovered that the 84 CR250 Has a piston that is identical 66mm bore 18 mm pin but it is a 246 cc instead of a 249cc displacement like the ke .Meaning the stroke is .75mm less on the cr. won't quite make it to TDC on the ke. Does anyone have any experience using a different piston in an engine other than one made specifically for that engine? is .75mm going to affect the compression ratio a great deal? has anyone used sealant for a base gasket instead of an actual gasket? I'm thinking if I did that I could minimize the stroke difference

thanks in advance!
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post #2 of 2 (permalink) Old 03-05-2017, 11:37 AM
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Join Date: Mar 2009
Posts: 4,464
There are many more considerations than just bore and pin diameters. A few include:
1. Pin location.
2. Skirt length.
3. Ring width and numbers.
4. Ring location.
5. Dome shape/location.
6. The stroke on your machine has not changed, so that does not count.

What is wrong with your old piston?

Last edited by sfair; 03-05-2017 at 11:46 AM.
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