i have a 05 kfx an i have a full yoshimura on it. it runs like it did before a pipe.....perfect. i did not jet it. should i? will a jet kit add hp?

 

Airbox lid on I presume?? If not, then someone already upped the main before you bought it. They won't run with the lid off with the stock pipe, let alone with an aftermarket.

Yes, upping the main to a 165-170, & the fuel screw out 3 turns with no lid will make a huge difference.

 

well im original owner. noone ever messed with the carb. the lid is still on. id like to keep it on there...

 

OK.... well then just be satisfied with what you have if you wanna keep the lid. You could probably up the main to a 140 and turn open the fuel screw 1/4-1/2 turn.

You shurely leaned it out some with the pipe, but not enough to hurt the engine. I'd still jet it up a little to maximize the power gains.

 

yah i was leaning toward a jet kit too. i race hare scrambles an would preferably keep box lid on. thanks for your input.