View Full Version : a few jetting questions
Jason250ex
07-16-2005, 06:14 PM
ok guys, i spent the better part of the afternoon working on my 250ex.... i have an e-series slip on and was going up from a 95 to a 100 main jet. however, i put the new jet on, and the carb leaked from the screw on the bottom of the carb and no matter what way we adjusted it, it would not run. it would idle fine, but would not rev above a few hundred rpm's....is this due to the fact that i didnt put on a bigger pilot jet as well?? i returned it to stock and it runs perfect, any advice is appreciated
Jason250ex
07-17-2005, 07:59 AM
up.....come on guys, nobody has ANY suggestions?
Bill Fuller
07-17-2005, 08:02 AM
If it runs fine with the stock pilot jet then why are you changing it??The pilot jet only effects the bottom end of the power,pretty much from idle to 1/8 throttle.
Jason250ex
07-17-2005, 01:40 PM
i didnt change the pilot jet, im looking for more power out of my pipe and got a bigger main jet, and it will not tune right... i do however have a new pilot jet on order b/c my idle is rough since the new pipe
White_Knuckles
07-18-2005, 09:15 AM
Changing out the main jet would not introduce a fuel leak. What do you mean by "bottom screw?"
There is the fuel or idle mixture screw on the side of the carb. There is a float bowl drain screw on the bottom of the bowl. I hope you weren't backing it out, that would make a dandy "leak".
Stock pilot will be fine. Back out (richen) the fuel screw if excessive backfire on quick throttle release.
Most likely you nudged the float out of position and it couldn't shut off the needle/seat fuel inlet. The carb was flooding over so it could barely run. The fuel would be pooring out the overflow. Did you remove the carb or swap the jet with it mounted? Slow down and try again. Pull the carb so you can see.
Jason250ex
07-18-2005, 07:55 PM
i think i may havve been loosening the drain screw? which one exactly is the drain screw and which is the air/fuel mix screw and how can i fix the float?
i took the carb completely off and apart, and its 6 months old and the float moved fine....ill read up some more and re read your post and try again tomorrow and post back, thanks.
Jason
hey jason where in la do you live. sorry the fuel/air mix screw probably isnt going to solve your problems, but you might try and lean it out a little. did you put that plastic thing back on the main jet when you put the carb back together. next time you take it off look and see if the main jet didnt fall out, i know it sound weird but it happens alot. it kinda sounds like you went too big on the main can you get a 97 or something. ohh and the drain screw is the one farthest down an the carb next to the over flow, and the fuel air/mix is usualy on the bottom of the bowl. i hope this helps
HondaEXrider22
07-18-2005, 08:28 PM
I have a 250ex with the same stuff as you(my sig) and i ahve m,y main jet at 112 and runs good. I just need to get around to richening the screw because it backfires ALOT on throttle release.
Jason250ex
07-19-2005, 03:31 PM
hondaexrider22, how do you have yours adjusted then? theres no way im too rich with a 100 ifyour running a 112...
HondaEXrider22
07-19-2005, 05:57 PM
The air fuel mixture screw? I have it at 3 turns and i took a small screw driver and bent it and it works i went 1/4 turn at a time(started at 2.5) and tested it out.
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