Hi guys

I did some minor changes on my Raptor 660 04'
-GYTR air filter
-GYTR Carburator neddle
-Open spark arrestor (cut) on a stock exhaust
that's it

I still have the 140-145 jet on the carb.

The low and hi engine speed are good, but the mid rpm range is bad
Sould I change the jetting ! 150-155 for example

Important: I must keep the STOCK EXHAUST.... I know, it's bad but that's it

Thanks