Re-jetting a 2006-2007 TRX 250EX

[ricky4568]

Hello I have a 2006 Honda Trx 250 Ex quad. The only mods I have done to it are installing a Uni air filter and a full Yoshimura Rs-3 spark arrested exhaust system. But after installing the exhaust I noticed it started to pop or backfire after letting off the throttle. Does anyone out there now what jet I need to run in my carb?? I think its running to lean.. Do I just need to change my main jet?? If so what size does it need to be changed to?? Keep in mind the stock main jet is a 95.. What about changing any other jets is that necessary??

Thankyou

Ricky

[tedwilley]

ricky4568, no offense, but do a search in this forum for "jetting" or "rejetting", it gets asked every two weeks.

**Read the jetting advice in the FAQs post at the top of the 250ex forum.

You will need to increase at least your main jet, probably between 106-112 (stock is 96 I think) and adjust the needle. Also, I believe none of the 06-07 models have an adjustable needle valve (my 07 didn't have one), so you will need a new adjustable needle (theres a picture in the FAQs post of the adjustable needle assembly).
Lastly you will need to tinker with the fuel mixture screw underneath the carb. Stock adj is 2-1/2 turns out from fully in.
Two good resource reads are the post "Explaining the Mysterious Fuel Screw" and the explanation of jetting on www.jetsrus.com
It is cheapest to buy individual jets, if you know which sizes to buy, or you can buy a kit for about $50. You will never use most of the jets in the kit on the 250. But, it is complete with various jets and a new needle.

Lastly, DO NOT believe those who claim that rejetting is completely unnecessary (especially with a full exhaust and free flow filter) You are running lean (the popping is the clue) and running too lean too long will cause a burnt exhaust valve and engine overheating.

[bigj250ex]

i think u shoul go 2 115 my bros running a 125 on his with hmf and it runnin good so yea like 115 0r 120