I just picked up a used KDX200 (01) a few weeks ago. The bike has a FMF Gold Series pipe, but it doesn't clearly say "torque" or "rev". How do I tell the difference? I'm really just curious.
Somewhere on the pipe (usually a mounting tab) it'll read -35 (torque) or -30 (rev). If it doesn't then you can tell by the diameter at the widest part of the pipe. The -30 will be something like 14" diameter and the -35 will be something like 11" diameter (if memory serves). The -30 almost touches the right radiator plastic cover. The -35 has about 1 3/4" clearance.
I thought you meant circumference!!! I was thinking a 14" diameter pipe might give you a little extra power but clearing the trees might be a problem!!!