[zobenv]

i purchased a 99 xc 500 with broken piston, when i took apart the ring gaps are toward the exhaust port. this is not correct is it? i do not have a manual for mach. the other piston is the same. this cyl is cast iron correct?
can this cyl be bored? thanks for any info
where can i download a manual on this sled?

 

[BC_Dan]

Not sure on the cylinder, but the ring gap is on the intake side. In the groove, there will be a locating pin. The pin fixes the gap so that the ring ends don't snag a port and tear up the cylinder.

 

[zobenv]

thanks, that is the answer i was looking for, that being said the pistons are installed backwards and the rings must of snagged on the ex port.

 

[JDS]

When I bought my ZR, one of the pistons was installed backwards as well. It had been rebuilt by a pro?

 

[kjackson7710]

Yes Pistons were definantly in backwards... Gaps on the intake side!

 

[zobenv]

ya know what is scary, this thing looks like it was never apart. don't know for sure, it has 2k miles

 

[BC_Dan]

The gap should be on the intake side. There should also be an arrow on the piston crown either pointing to the exhaust side or to the flywheel/recoil. If the ring gap is on the exhaust side, the piston was installed backward. The locating pin can fall out, which allows the rings to turn in the groove, and when the ring gap gets to the exhaust port, the end of the ring snags the port. That happens from time to time, but usually to only one ring.