jetting for my 250ex

[WickedRider]

this xmas im getting a wb e-series complete & a K&N jet kit, i was wondering if the instructions that comes w/ the exhaust has recommended jetting sizes, or if any1 has rejetted a 250 jet me know on wat worked best 4 u. im goin 2 take off the carb on a trx90 that we have, to practice. thanx later.

[cals400ex]

directions will come with that jet kit. they will also supply you with a needle. you actually don't have to buy the jet kit and can buy individual jets if you want to save some cash. just an idea. sorry, i don't know what jets to use in a 250ex.

[ryanh250ex]

hmmm......i run a PC T-4 complete system and a stock airbox and stock filter and run a 100 main jet....i used the OEM Honda jets designed for Keihin Carbs.


i put the STOCK needle at the 4th groove from the top, or one groove below stock.

i'm not too familiar with the WB systems, but i do know that they are a disc system, so the jetting will be determined by how many discs you have in. btw, are you SURE you're getting a WB COMPLETE system?? i was pretty sure they only sold that pipe as a slip-on. they may have just released a header for it that i'm not aware of, but i dont know.....i've been wrong before.

i would say that with the K&N filter, and the pipe and the opened airbox, you'll probably have to run somewhere around a 110 main jet.while chances are i'm in the ballpark, this will most likely not be exact, because i dont know how many discs you plan on running, nor do i know what your elevation is.

dont bother taking off the trx90 carb, just about anyone with a pulse can rejet a 250ex. it's rejetting it CORRECTLY that is the hard part. it is from my experience that these bikes can be very tempermental with jetting. being one jet size off can make a pretty big difference in performance.

hope i helped.

[WickedRider]

yeah i went to a shop & i could get a complete for 289.

[WickedRider]

i changed my mind. im jus goin 2 get a hmf slip-on. its only a round 230. & 5 bucks for the jet. im thinkin about getting 1 in black.
http://www.hmfengineering.com/honda250so.html

can some1 tell me if those specs are right jus for a slip-on?
thanx

[cals400ex]

hmf's jetting recommendations are usually high. i know that was the case for the 400ex and the rancher. whats the stock jet size and what do they recommend? however, your jetting will change as the temp changes. i usually change my mainjets 3 times a year. however, 2 times will be enough.