MXZ Piston meltdown help - Snowmobile Forum: Your #1 Snowmobile Forum

Ymmit1 · 12-20-2004, 08:40 PM

what happens if you install a pison into a 2 stroke with the ring gap towards the exhaust side? I was working on a 99 MXZ 600 I bought used and one of the pistons was melted down on the exhaust side. It was melted right from the ring gap outward. I was trying to figure out why it melted when I realized the piston was in backwards. Would this cause it to melt the piston?

YamahaVector · 12-20-2004, 10:10 PM

I would think that it melted due to the engine running lean. Was the ring still intact? The problem that I could see happening would be for the ring to catch in the exhaust port and cause damage.

Ymmit1 · 12-20-2004, 10:17 PM

Yes the ring is still intact. It was running right over the exhaust port but it didn't break or wear a groove like I thought it would. the melted area started right at the point of the ring gap and went outward from there. I am afraid of a lean condition but thought possbly the gap being on the exhaust side could cause a hot spot.

**smallengineguy** · 12-20-2004, 10:28 PM

Vector had it. The ring gap goes on the opposite side to prevent it from catching the exhaust port. It's got a lean condition.