I am wondering how big the fuel jets are in the carb on my 2004 yamaha warrior 350 I think they are stock but I want to put bigger jets in and don't know what size to get

 

145 main jet, 42.5 pilot jet. 2004 Yamaha WARRIOR (YFM35XS) Carburetor | Cycle Parts Warehouse

 

Thank you very much

 

What size will I need to put in with a performance exhaust and air filter?

 

All depends on what the plug looks like and how it runs. Some I've found that stock jetting was fine. Plug chopping,that is killing the machine after it's warm and at a good speed. Let it cool down and check the plug color. You're looking for a medium tan or light brown color on the electrode.If it's whitish then the main at least needs to be bumped up. Old rule of thumb was to allow a 15% increase on jetting and have at least a couple over size jets on hand.Here's a good site on jet sizes for your Warrior.https://www.jetsrus.com/a_jet_kit_at...0X_warrior.htm Fine tuning can be adjusted also by moving the needle clip up or down on the jet needle.

 

You might try a Dynojet Stage 1 kit and drill the slide, if you haven't already. I run a Web race cam, K&N and removed the restrictive spark arrester tube and run a 5 degree timing advance key on my Arctic Cat 500. I have an AEM wide band A/F and ended with stock pilot jet (38 Keihin) and went from a 150 to a 155 Keihin main jet. I just had a bunch of Keihin jets, but the Dynojet ones will be fine. I think you will only need 1 size bigger main and play around with the shim height with the Dyno jet needle. Their suggestion will be very close.The safe way to to get the right main jet is to check top speed, then go up a jet size and record the top speed, then go up until speed drops. The jet that gives you the best top speed will be the best. If you want to be totally safe run 1 size richer.

 

OK thanks