jetting ???

[Moto250X_Rider]

:cool: i got an HMF sport slip-on and u sent me a 125 main jet well when i went to put the jet in i already have a 125 jet in my carb so i tried running it with that jet and i'm still getting backfire so i know i'm running lean....also i don't think my pilot jet is the right size does not want to stay running(idles funny)i'm sure i have to go bigger with my pilot jet when i turned in my fuel screw it shut down....when i turned it out it didn't shut down.... i have a Honda 250X 1987 what main jet and pilot jet size will work best and how many turns out should i set my fuel screw??

[motoz/HMF]

:cool: i got an HMF sport slip-on and u sent me a 125 main jet well when i went to put the jet in i already have a 125 jet in my carb so i tried running it with that jet and i'm still getting backfire so i know i'm running lean....also i don't think my pilot jet is the right size does not want to stay running(idles funny)i'm sure i have to go bigger with my pilot jet when i turned in my fuel screw it shut down....when i turned it out it didn't shut down.... i have a Honda 250X 1987 what main jet and pilot jet size will work best and how many turns out should i set my fuel screw??


1987, are you the original owner? someonw may have changed the main jet before you.
Does that carb have a fuel screw (on the bottom of the carb by the float bowl) or an air screw on the right side of the carb by the intake?
It makes a difference...

Let me know which you have and we can go from there.

[Moto250X_Rider]

it's a fuel screw buy the float.....no i got it off a friend about 2 1/2 years ago and i asked him and he said they never did anything to it,thats the stock jet .the book for that year and for the 88 said that the stock jet is a 125 ....the 1990 and 1991 have a 122 just like the 300ex...so i think the 87 and the 88 250X have a different carb size from the 90,91...and the 300ex i also checked with a few ppl and they told me the same thing that the 125 was stock in the 87 and 88's cause i thaught it was a 122 in there at first also just like the 300ex but it's a 125

[motoz/HMF]

:cool: i got an HMF sport slip-on and u sent me a 125 main jet well when i went to put the jet in i already have a 125 jet in my carb so i tried running it with that jet and i'm still getting backfire so i know i'm running lean....also i don't think my pilot jet is the right size does not want to stay running(idles funny)i'm sure i have to go bigger with my pilot jet when i turned in my fuel screw it shut down....when i turned it out it didn't shut down.... i have a Honda 250X 1987 what main jet and pilot jet size will work best and how many turns out should i set my fuel screw??


Ok now which throttle position are you getting the backfire in?

0~1/4 is the fuel screw, pilot jet.
1/4 ~3/4 is the needle clip position.
3/4 to WOT is the main jet.

Determine which throttle position you are having the problem in and adjust accordingly.