i was wondering if the 450r is re jetted when the hrc power kit is added? because i know they take the baffle out of the muffler.

 

Yes, but I don't know what jets they spec for it.

 

185 main and a new needle come with the kit.

 

would it make it run different if the air box lid off or should it be run with it off in the first place

 

It's already LEAN from the factory, so I wouldn't pull it off unless you're going to rejet. If you just opened the air box and exhaust, you could probably run a 168-180 main jet. 118 is the stock main.

 

I cut open the airbox lid and put in a 2" end cap in the muffler. I run a 180 main jet, 50 pilot jet (up from 48 stock) and dropped the clip on the needle to the 5th position. With this set up I didn't have to mess with the fuel mixture screw.
I have also added a hotcam stage II. It runs awesome