o, well expect about a 4-5 PEEK Hp increase. Remeber, its not about PEEK Hp, its about usable hp, with the mods you get a fatter powerband. im not sure how much stock HP the rappy makes at the flywheel.

 

If you buy an exhaust, filter or jet kit, the hp numbers the box says you will gain are almost always bull sh*t! The guy that said you only have about 24hp max is prolly exactly right. And if you are getting 24hp at the crank your prolly getting 16-17 at the wheels. Run it on a dyno and i bet these numbers will be pretty accurate. IMO

 

Stock raptor 350 is 22, hmf says 21, they only gain about 1 peak HP with the sport series pipe, check the site for the dyno runs, but you gain alot more in the midrange, its probably like a 3-4 hp gain through the fat part of the powerband. Opened up and jetted properly i would say your maybe at 25 hp at the most. The headpipe you have did ABSOLUTELY nothing for you expect look pretty, so don't expect much more from your pipe then the HMF. Without tearing into the motor, cam, piston, etc. your not going to break 25.

 

How much hp would a 2002 300ex with a full dg exhaust,jetted,k&n filter with 20" rear tires 13/36 gearing?