I have one JP RS12-T1 which I bought in July this year. This engine is powerful but laterly the power have reduces. Can you advise me what to do to increase back the power. This engine have run 3-4 races and clean it every two races. Any suggestion on the pipe or manifold use. Currently I am using Novarossi tune pipe and manifold. What is the suggested length for my tune pipe and manifold. The engine compression is still ok. As my weather here is hot I usually use Novarossi No. 7 cold plug. I hope you can give me some tip on this engine.