I 'm aware it may or may not be neccessary to change out the main jets, what about the needle jet?

 

If the only change you have made to your '03 P650 is a Twin Air filter, you should not need to rejet at all.

 

What if I install DG or NYROC snorkle, then should I?

ps Have family in Gouverneur

 

Air Filter you can get away without jetting, Stock is a little on the rich side already. If changing over to a DG Snorkle or doing a muffler mod you'll more then likely wanna rejet. I would ask nyroc what he runs if doing his mod along with asking DG. I beleave Nyroc has info on his web site as well? ~coop

www.MarylandATV.com
Prairie 700
Team Green Plastic
Progressive Springs
OMF Beadlocks
Maxxis Big Horns
Dyna CDI
EPI Pink Spring
Twin Air Filter
HMF Penland Pipe
And a Bunch of other Toyz

 

I have the snorkle and a twinair and have not rejetted at all..the only thing ive noticed is a bit of a pop on occasion from closing the throttle

 

If you go with the Twin Air, DG Snorkle, and the muffler mod, you may well have to rejet. Best way to tell is to make the mods, then do plug checks. I have those exact same mods and rejetted 142/145 and needle shimmed .040. Works well for me. However, the easiest mod, with the most noticable gain, that I have made is the Dynatek CDI. Takes 2 minutes to install and power gain is very noticable.

 

Metallikev,

I have found when I get a pop when engine breaking with the throttle closed that my idle is too low, starving the motor for some air. Idle up a tad and see what happens.