Getting into 120 racing? Looking for advice for stock 120 class?

[Polaris Racer 169]

I am getting my son into the 120 racing scene. He loves it and its great to see him race. He has a stock 120 for now and I'm trying to figure out all the ISR stuff we should do to make it as competitive as possible. I have been on rec motorsports and got the adj main jet, governor spring, gov arm nut all coming. Not sure on the ISR valve springs listed. Also curius about a gear I heard about replacing because of gov bypass??? Dont wanna break anything.
Also, could use gearing advice. He's 4 yrs old and a good rider so I know he can handle anything I can do to make the sled the best possible. Figure I'll get this stock sled all dialed before I get going on a mod for him!
Thanks for any help and advice. It is greatly appreciated.
Dolan

 

[Racer220]

I'm in the same boat Dolan. Bear Lake was a blast, but I have a lot of work to do to get set up right. All my son can talk about is going to his next race lol. You might chat with Bob at Afton if you get a chance. He seemed to know quite a bit about setting these up for racing.

Anyone with some experience please post your setups for us based on using the stock motor.