I am putting a Big Bore piston in my 99 Scrambler 400. The guy told me he'd plug the decompression hole. (A hole in the cyl.bore above the exhaust port to aid in starting) That it would make a differnts in the way it runs. He done it to his Polaris snowmobile 3cyl. He is going to plug it with a aluminum plug so if needed I could drill it back out. IS THIS TRUE ???

 

Has anyone heard of a Decompession Aid on a 2-stroke

 

JWC,

The port that you are talking about is a non-issue at operating RPMs. It does make a difference in starting the quad because the piston is moving slower than when the engine is actually running.