2 stroke fool.

[custm2500]

I have a 2013 Indy SP 600. My first trip up north to the UP I killed the right side (stator side) piston. I bought a matching used cylinder and piston put it together and everything was good for a few hundred miles. It appears that the power valve caught the edge of the piston. What can I do or what measurment do I need to confirm that they don't touch again? Is it posible that there was a leak that didn't hold the power valve open? It ran fine for around 500 miles then started making noise and miss firing. The only issue in those 500 miles is when I was at higher rpm and went full throttle it would go into limp mode. Shut it off and tried it again(replicating the hard throttle to condfirm issue) then after that I just stayed at 3/4 throttle and never had an issue untill it went down hill quickly.
https://drive.google.com/file/d/1399ftd4Cm8HWNX_BWfgQpt77At0LkWUf/view?usp=sharing

 

[custm2500]

I did reuse the original gasket as it was in perfect condition and stayed on the power valve 100% I can't imagine that would be enought to allow contact but I am using all new gasket this time.

 

[Tunneltwister]

Did you clean your power valve while it was out...? If so make sure the valve was reinstalled right side up. If you look at the blade you will notice that one side has a more dramatic chamfer on it. If it was reinstalled upside down I could see that..

 

[custm2500]

It wasn't dirty, but i didnt clean it or the cylinder bore that it goes in. I certainly will this time!

 

[gtwitch]

Call Indy Dan He can machine the exhaust sliding valve as they relieve themselves into the cylinder as they get older and will contact the pistons and trash them most of the time . I have lost two cylinders before I figured out how to machine the EVs. On all of my Dragons (4 injector) and Pros I have machined the EVs at the first opportunity when I clean them the first time.
gtwitch in wyoming

 

[custm2500]

Machine them sounds like a quick hit to the tip with a scotch bright disk...

I will clean them both really good for sure. The sled only has 1500 or less miles.

 

[custm2500]

Call Indy Dan He can machine the exhaust sliding valve as they relieve themselves into the cylinder as they get older and will contact the pistons and trash them most of the time . I have lost two cylinders before I figured out how to machine the EVs. On all of my Dragons (4 injector) and Pros I have machined the EVs at the first opportunity when I clean them the first time.
gtwitch in wyoming

How often should I clean them?

 

[custm2500]

I did reuse the original gasket as it was in perfect condition and stayed on the power valve 100% I can't imagine that would be enought to allow contact but I am using all new gasket this time.

After getting the cylinder today I realized that there is a collar that dictates where the valve stops, and the gasket isn't part of the equation.

 

[gtwitch]

I usually clean my EVs twice a season on our 4 PRO 800s (800-1000 mile season) and you need to take at least .020 to .030 from the curved end of the EV at the same angle it is now and this can be done (cheap way) with a belt sander if you have or a friend has an upright belt sander. I have done this both ways and i have access to a programmable nc mill but when I do not have access to that, I have done it by being careful and using my belt sander here in the shop at home.
gtwitch in wyoming

 

[custm2500]

Thank youn, great info!