dyno jet

[sandnmyteeth2]

I installed a Powerbomb header on my EX and it started popping. I picked up a Dyno jet kit and installed it according to the directions. I put the needle on the third groove. I replaced the 165 main jet that was in the carb. with the 165 that came in the kit. The fuel mixture is 3.5 turns out from seated. Now my bike will start and idle fine, but will not accept any throttle. Any suggestions? Thanks.

[Mike[socal]]

What's your elevation? What mods do you have? I have an 02 400ex, no lid, k&n, and an Alba slip on. I have the dynojet kit with the 155 main(probably a little lean), dynojet needle in 3rd clip(no washer), and screw about 3.25 turns out. I ride at about 250 feet above sea level. Where does you bike start to break up? 1/4, 1/2, 3/4 throttle?

[khen]

Sounds like you're lean on the main jet to me.. I'd go 2 or 3 sizes(dyno jet sizes) up on the main jet and go from there. If when you throttle up it sputters it's usually rich if it just dumps out it's usually lean.

[UglyMotha™]

Originally posted by khen
Sounds like you're lean on the main jet to me.. I'd go 2 or 3 sizes(dyno jet sizes) up on the main jet and go from there. If when you throttle up it sputters it's usually rich if it just dumps out it's usually lean.


He said he can't give it any throttle, considering mainjet is only 3/4 to wide open, how is the mainjet goin to fix his problem, sounds like his problem starts soon as he gives it throttle so wouldn't his problem lie in the air/fuel screw, pilot 1/4 throttle or the needle 1/4 to 3/4 throttle rather than the main jet, main jet could have a issue but don't you think you would want to start at the bottom and work your way up, kinda senseless to work backwards

[400exrider707]

What does the plug look like. Did you change your pilot jet? You will want to do that if you already didn't. Also you can just email FMF for recommended jetting and that will get you in the ballpark, then from there you can fine tune it.

[khen]

Originally posted by UglyMotha™
He said he can't give it any throttle, considering mainjet is only 3/4 to wide open, how is the mainjet goin to fix his problem, sounds like his problem starts soon as he gives it throttle so wouldn't his problem lie in the air/fuel screw, pilot 1/4 throttle or the needle 1/4 to 3/4 throttle rather than the main jet, main jet could have a issue but don't you think you would want to start at the bottom and work your way up, kinda senseless to work backwards The main reason I suggested starting with the main jet is because he went from a 165 Keihin main jet to a 165 Dyno jet. They don't cross over, and my understanding is that the Dyno jet is going to be leaner.

EDIT: Oops my bad, after further investigation it looks like it's opposite.. the dynojet is going to be richer. :confused:

[sandnmyteeth2]

Im at 1100 feet, temp is about 60 , no lid on air box. Rest of mods. listed below. THANKS

[Mike[socal]]

This may be a stupid question but did you include the spacer below the main jet?

[sandnmyteeth2]

Yes the spacer is there. I think I found the problem the slide was stuck open. its running better but now its idling high.It will rev up now.I will mess with it more tomorow. THANKS

[cals400ex]

make sure the throttle cable and slide aren't sticking. also, make sure you have about 1/4 inch of slack in the throttle cable. much less than that and your idle may raise by itself. much more than that and you will be greatly sacrificing power.

[01/416ex]

I was just going to tell you to check that , I just took the Edelbrock of and put my stock back on and the slide was hung open and it was doing the same thing , idle like a champ and you try to hit the throttle and it would pop and shut off.