i know that a raptor from the factory isnt jeted to perfection. i realize it isnt possible also to get perfection, but what are some recomendations, what jet sizes? i have heard that just jetting it correctly adds a bit of power, just he jetting alone w/o removing the lid or adding mods. so what is the best stock jetting to run in a raptor 660? thanks-rider1169

 

The best way to jet, i believe, is to read the spark plug. It's a long and hateful process.
Run the bike hard then pull the plug:

Black= too rich, jet size needs to come down
White/chalky=too lean, jet size needs to come up
Brown coloration=good to go.

With my raptor, which has motor work, this method has always worked for me.

Just remember, if you make change (airbox, exhaust, etc.) do it all over again.

 

well, do u go up or down 5 at a time, say its 150/155- go to either 155/160, or 145/150?

 

If you haven't made any mods then I'm assuming you have stock jets.
Jet up or down in increments of five. IE: If your plug is black, and your jetting is 150/155, then step down to
145/150. It would be hard for me to guess what sizes you need because we live in different parts
of the country and are at different elevations.

I would reccomend, however, that you cut the top of your airbox lid before rejetting. Gotta have more air to make power with more fuel. Plus, you can pickup another airbox lid cheap if you ever need one.

If you really want to see a serious power gain, get a Curtis Sparks pipe. That all by itself, with the right jetting, will turn it into a different machine.