I need help please. Got soaked on purchasing a 99 600 RMK. Turns out the engine isn't stock and has a pipe. The engine is a 600cc, not sure of the year, and it has a single aftermarket pipe, not sure of the pipe manufact. My problem is this, the engine runs fine, 500rpms on idle (might be low). Bottom end is good, but Rpms don't exceed 3000 rpm ever! 40mph if i'm lucky. It has 340 jets in the Mukini carbs, with 10M5 clutch weights with a dark blue primary spring. Would stock 10-54 or 10-55 weights help engine performance. Thanks for the help!