In the next month or two i will be purchasing an hrc kit, and a hmf exaust pipe. I know that some pipes you have to have the carb rejetted, so if i was to purchase a hmf sport series or ballence series pipe, would i have to rejet the carb?


thanks

 

with any change to the way an engine breaths (be it in...intake- or out...exhaust) you should rejet to get optimum efficiency and power. The larger the engine, the more you will probably have to change. Someone with the hmf on the r can probably be of more help, as I dont even know what the stock jet sizes are. Expect to go up around 2 full sizes on the main, possibly richen the pilot, adjust the fuel (or air, dont know what the 450r carb has) screw, as well as possibly adjusting the needle.

 

The HRC kit should come with a 180 main(or 185 i forget) and a Needle jet,,,If not,, with the HRC lid and a pipe you should be at about a 180 to 185

Its amazing but by going to an open lid and an exhaust your main jumps from a 118(stock) to a 180

 

sparks seid with ther pipe to change the mane jet to a 190 and the needle to the 3rd position
but did not say on the pilot