I was wondering, if I bore my 660 raptor 40over and add a stage one hot cam do I have to run an after market exhaust??

 

no, but if you want to go fast than hell yea

 

Why would you bore the bike out at all? And why do internal engine work to gain 2-5hp when a bolt on pipe and filter change can yeild 8-15?

Unless you got a heck of a deal on the parts or are trying to build a sleeper.

 

The best thing to do is take the cork out of her first man.

 

just stay with the stock bore maybe put a 11:1 piston in and put a pipe and jet it, get rid of that junky airbox and get a clamp on k&N.

slap a 12 tooth stocket on, and that thing should rip and go with the stage 2 cam stage 1 doesnt have much of an increase...