Thats a good quetion, they say just putting on slip ons does not require to rejet. (with stock air filter) if you put a k & m air fileter on they say you prob. will.

Now my bike is poping (back fireing) ever so slightly win I get off the throttle quick worse with some gas than others but is always just waiting to pop, so I have no idea if this is going to make it worse I shore bet its gona be a louder back fire now if it does :(:hat