jetting. HELP

[bigboyz250r]

i have a 91 trx 250x. just put a fmf full exhaust and k&n filter. i see that they dont sell a jetting kit for that carb. does anyone know what size jets i have to put in? or since they are so similar to the 300ex should i just switch and run a 300ex carb? please help thanks

[400thacker]

I am pretty sure that the 250x and the 300ex use the exact same carb. I am not 100% sure but I know i am running 300ex carb on my 250 and I can't find any visual differences at all.

here is a link on ebay for your net kits for the 250

http://shop.ebay.com/i.html?_nkw=trx250x+jet+kit&_sacat=0&_odkw=250x+jet+kit&_osacat=0&_trksid=p3286.c0.m270.l1313

or you can just search for "TRX250X jet kit"

hope this helps

[400thacker]

well after i looked, those are for the new 09-10 trx250x quad that honda just came out with.

call your local shop and ask them if the part number is the same for your 250x and the 300ex. if they are the same part number then you can buy a jet kit for the 300

[bigboyz250r]

the carbs are different. but im wondering if it would be better to just switch it cause its easier to get parts for.

[400thacker]

well 300ex carbs are pretty easy to find so if you are sure you can't get a jet kit for the 250 that is what I would do.
I would try to put a 250x and 350ex jet side by side to be sure first that the jets won't interchange first.
no point in buying another carb if you don't have to.

[400thacker]

and i forgot to mention, if you have any performance mods I would suggest looking at a 400ex carb. I remember reading up on it and the 400ex carb will work with the 250x intake boot.

[bigboyz250r]

yeah the carb i got now needs to be rebuilt which isnt a problem. but i just put an exhaust and intake on it. if i can just buy the jets seperatly and do it like that it would be perfect im not looking to really buy a new carb.

[dman66]

Just take your old jets out, take them to your local Honda atv dealer, and they should have replacement jets you will need, if they are a good parts shop. I believe you will be around a 130 - 135 main jet, and a 40 pilot jet,the needle clip will stay in stock location. This should get you in the ballpark.You need to get some new spark plugs to monitor how the engine is burning ex: too rich/too lean You need it inbetween those two. I would go a 130 main and a 40 pilot. The 40 pilot will almost eliminate the choke operation. Your air/fuel screw will be about 2 1/2 turns out. DON"ING REBUILD!!!!!!!!!!!!!!!!!!!!!

[dman66]

Depending on what year the carb is from, the rebuid kits should be the same. I believe the designs are the same.The air/fuel screw changed a little, and some year carbs for the 300ex had a larger opening/outlet. From some of the trusted guys on other sites say, that the 400ex carb is a pain to dail in,but there is a noticable difference in power gain when you install a 400ex carb. I'm happy with my 12:1 compression 87 250x,with a rejetted carb, for trail riding.