i just got an 87 r that i love, but, i dont know if its because of the extreme cold here (about 8 degrees) or something else, but my r bogs bad in the mid range. maybe i dont let it warm up long enough(about 2 minutes)? i trust the guy i got it from, so i dont know. what should i look at?only motor related upgrades i know of is the k and n filter and an lrd pipe and silencer