Just purchased a new K&N X-treme power lid kit. The kit comes with a jet kit to install with the lid. I'm wondering if anyone here has one installed. My 03 660 Raptor currently has a full Yoshi exhaust with a K&N filter and has already been jetted for those to mods and runs perfect. My question is will I need to rejet to compensate for the new lid, or will the current jets that have been set up for the pipe & air filter be ok, and what are the signs of the bike running lean if I run the bike with the lid and the current jets?

 

Take it back quick! I have the exact setup as you 03le, full yosh, k&n, powerlid. Unless you need the protection of the lid, you WILL lose power. If you are still determined to use it (I do for mudding), IGNORE k&n's recommendations. They could not be farther off.

If you are jetted for your setup with no lid, drop one size on your mains and try 1/4 turn leaner on your fuel screws.
If you are jetted for the stock lid on, go up one size on mains and 1/4 turn richer.

The needle should be fine.

I'm at 155/160, 3rd clip, 3-1/2 turns at 60 degrees and 300 feet elevation.