Which jetting for 440ex?

[Raptor4439]

I just got it bored and im having trouble with it, when I hit 3/4 throttle it bogs and wont go past that. I talked to a few people and they say that I need a bigger main jet, I just need to know what size I need to get. 160? 162? Also when I started it up since the rebuild it had a pinging noise coming from it and it wouldn't stop, keep in mind that this is the first its been started up. Oh yeah, I have the stock air box/filter and I have the stock pipe with the baffle sawed out.

[cals400ex]

Originally posted by Raptor4439
I just got it bored and im having trouble with it, when I hit 3/4 throttle it bogs and wont go past that. I talked to a few people and they say that I need a bigger main jet, I just need to know what size I need to get. 160? 162? Also when I started it up since the rebuild it had a pinging noise coming from it and it wouldn't stop, keep in mind that this is the first its been started up. Oh yeah, I have the stock air box/filter and I have the stock pipe with the baffle sawed out.

go ahead and try a 155 mainjet. i would also raise your pilot jet up to a 40 or 42. however, i think you have more problems than jetting if it won't run past 3/4 throttle. i know the pinging can't be good.

[Raptor4439]

Oh I just fixed it, the timming was off by a tooth :eek2: but it pulls like a beast now. I left the jetting stock but I just ordered a dyno jet kit from motoman.

[cals400ex]

i was going to post that about the timing yesterday but i forgot and i hit the submit. so, i was going to mention that today but you already found the problem. glad you got it fixed.

[Raptor4439]

I just got the jet kit from motoman today and I installed it in the 440 with a 165 mj. it has a stock pipe/airbox with the lid removed. The baffle is sawed out of the pipe also. It will idle fine and when I get on the gas it dies, its like it's running too lean. Can someone help me out and tell me the correct jetting for this thing?

[TCracin440ex]

bro whats gonna fix your problems is your running aftermarket motor mods u gonna have to get a b etter air filter......K&n a cheap slip on exhaust...and this should pretty much fix all your troubles

[cals400ex]

Originally posted by Raptor4439
I just got the jet kit from motoman today and I installed it in the 440 with a 165 mj. it has a stock pipe/airbox with the lid removed. The baffle is sawed out of the pipe also. It will idle fine and when I get on the gas it dies, its like it's running too lean. Can someone help me out and tell me the correct jetting for this thing?


what pilot you running?
whats your fuel skrew location?
whats your needle clip location?
are you running the washer under the needle?
i assume your using the dynojet needle that came in the kit?

[nikejoe]

What is the stock main and pilot jet size in the 400ex???:o

[Raptor4439]

the stock mj is 148. I dunno bout the other. okay I did another jet test today at 148 and it helped a little on flat grounds but when I go to climb a hill it boggs and will barely go up it, when the quad's sittin still and when I rev it, it revs perfect no backfire or anything. I pulled the spark plug too and it was smut black on the end. I need some help..gotta big riding trip tomorrow and I need to get this thing on the dirt again.

[cals400ex]

a 148 keihin would be too small. it is the stock size mainjet. i would make sure the mainjet or the two skrews holding the needle down didn't fall out. i am not sure what else to think unless you have an air leak or and electrical problem. i assume your choke isn't on by accident?

[Raptor4439]

dude, I check the choke before I crank it everytime, im not a total loser :blah: I think I got it to work with a 152 MJ. it revved perfect from bottom to wide open and deaccelerated completely w/o any interuptions. Is that the rev-limiter when it chops up top? it just builds until that and then it chops kinda in a steady pattern. but anyway I think it's fixed now but only a test ride will prove that and I couldn't last night at 11:30 :D

[cals400ex]

yeah, its probally the rev limiter you hear cutting out. hey, i never said your were a looser. i just see that here and there even with some experienced riders. glad you got it fixed.

[Raptor4439]

Just got back in from a test ride and man that thing is a monster. thanks for your help. I know you didn't say I was I was just kiddin around.