Mach1

Hi everyone:
I rode snowmobiles and motorcycles until I was 16 or 17, I've had motorcylces but this is the first sled I have owned. It's a 93 Mach 1 670, I've ridden quite a little in the past three years, mostly rentals. I like to ride hard and fast, boondock and climb hills and of course trails. My younger brother has always had sleds so he is probably my mentor so to speak. Ok here's a few questions

what can I do to improve the rear suspensions? without spending 12 to 1500.

Does porting the cylinder affect carburator jetting? Also a site that explains carburators and jetting

PTO side and MAG side, which is which? I'm assuming PTO = CLUTCH
Any help given will be much appreciated

Thanks