I have a 2003 model Suzuki LTZ 400 four wheeler that for some reason acts like it is in reverse when it is in drive and will not rev, I didn't know if there was anything to do so I could bypass the rev limiter for reverse because obviously the rev limiter still thinks it's in reverse when it's in drive and is always staying on and I need to bypass the rev limiter so the engine revs clean again.

 

I don't know the LTZ400 but most reverse rev limiters work by an extra wire from reverse light circuit to CDI, try disconnecting this wire and see if it now revs OK.