Few questions about my new build!

[Jesse400ex]

I finally got her back to gather! Here are the specs, 406cc Namura piston 11:1, stage two hot cam and HD cam chain, ground out welds, hmf slip on, K&N open airbox and dynojet kit. I finished the brake in procedure this afternoon and just started running it a little harder, what a difference, like night and day.

I’ve got a few questions, for you guys. From what I read about jets you want to start rich and work your way down, the dynojet kit came with stage 1&2 witch was 146 to 170 main, it has 170 in it now and it seems to run good, no pops or sputter.

I have noticed when its idling and you give it wot it almost sounds like it chokes, tries to die. Do I need to up my pilot jet? I haven’t messed with the needle or fuel mixture screw yet. Dose DJ 170 sound about right or dose is that rich? Just looking for some pointers, I want to make sure I’m getting the right amount of fuel.
Thanks for the help

[Jesse400ex]

some help please?

[4reeds]

Did the kit come with a needle? Try turning the f/s in untill lightly seated and then turn out 2.5. You can also try the pilot. Pull your plug after a few rides and check the color.

[JOHNDOE83]

dyno jet isnt for proper jetting, its a ballpark estimate, that puts you in the OK range....it is fine to use, and wont give you any issues.

dynojets are not numbered the same, a dj 170 is like a 190 kehin jet, I dont recommend using their needle, the stock needle is fine for almost any 400ex application.

for the kit you bought, just follow the directions, if you wanna jet it again in the future, buy jets from www.jetsrus.com and go through the jetting procedure you described.

[TRXRacer1]

Get working on that mix screw. You'll probably be in the 3 turns out range. I'm with JD, the stock needle is the one to run. That stutter when you punch it is probably just a lean pilot circuit. The mix screw controls the fuel flow of the pilot jet so if you need to you can go 3.25 turns out before needing a bigger pilot.

[Jesse400ex]

Thanks for all the help guys, I will try adjusting fuel mixture screw, what should my stock or DJ needle be set on?

[Jesse400ex]

I adjusted that damned fuel mixture screw, I bet I took the carb off ten times and now it dose it a bit worse. I set it at 2 ½, 2 ¾, 3, 3 ¼. I cant get anything to work. When I punch it stumbles and dies if I don’t let off. I’m ready to throw it in the damned trash if it would fit.:mad:

[JOHNDOE83]

If you put your needle on the third clip, and are still having this problem, like trxracer said, you may be lean on your pilot jet, he said to try the screw and if it still acted up, get a bigger pilot jet.

Thats where I would start before getting to frustrated.

jetting and tunning can be a pain, take it one step at a time.

Try to get a 40 pilot and a 42, to be safe.

[Jesse400ex]

Well I’ve been tinkering with it for a while and got it pretty close but still just a little stumble when I punch it but after it got warmed up it ran pretty good. Now what is the needle set on from factory? And is DJ 170 main to rich?

[TRXRacer1]

A DJ 170 is huge! Try something in the 160 range for a DJ jet.

[Jesse400ex]

So if it is running good now, you think I still might be to rich? I just don’t to want to run lean, I’ve read to many horror stories about running lean.

[TRXRacer1]

Originally posted by Jesse400ex
So if it is running good now, you think I still might be to rich? I just don’t to want to run lean, I’ve read to many horror stories about running lean. You said it's not running good... there is still a hesitation. You're running the equivalent of a keihin 190 main. It is possible that your low was too lean and your top is too rich. Not being there to tune it myself it I'm just guessing but that sounds huge. If it were mine I'd do a decent sized drop like earlier suggested and see what happens. Did they give you a 165 in that POS jetting kit? Maybe start there. Also unless you bought it brand new don't assume where the needle is by stock spec. Pull the carb out again, change the main (if I'm wrong it will still tell you were you need to be) and find out what clip the needle is riding on. If you have newer non-adjustable needle then use the DJ.

[Jesse400ex]

Thanks for all the useful information. I don’t mean to sound confusing, it dose have a hesitation when it sits and idles and I punch it WOT, but when I’m riding down the road it seems to run well, no pops or struggles. Tomorrow I will pull the carb off again and see were the needle is and set it at 3rd clip and put a smaller jet in, I have a 160 and a 165, I will try one of those. When I ordered the kit I didn’t know it was junk, I guess live and learn. Thanks for the help!

[TRXRacer1]

Originally posted by Jesse400ex
Thanks for all the useful information. I don’t mean to sound confusing, it dose have a hesitation when it sits and idles and I punch it WOT, but when I’m riding down the road it seems to run well, no pops or struggles. Tomorrow I will pull the carb off again and see were the needle is and set it at 3rd clip and put a smaller jet in, I have a 160 and a 165, I will try one of those. When I ordered the kit I didn’t know it was junk, I guess live and learn. Thanks for the help! DJ can be good but for the most part it's a BS company. In the future unless you absolutely need something in the kit then just go to RMATV or JetsRus for mains and pilots.

[JOHNDOE83]

from what I remember from DJ was the stage 1 and 2, you are no where near stage 2, stage 2 is for the big bore kits pipes and cams.

a 406 is not a big bore, so your still in stage 1, try the DJ146 thats equivelant to a 160 keihin.

right now 170DJ is equivelant to a kehin 190...440 big bores need those not 406.

a DJ 146...aka kehin 160, might even be a lil big. but better then the dj 170 for sure.

In the directions follow for stage 1, not 2.

[Jesse400ex]

If I go even lower on the main and it ends up being lean, how will I know, pop and sputter and what will it do if its rich. I am a auto mechanic and this is my first experience with a small engine. Thanks

[TRXRacer1]

Originally posted by JOHNDOE83
from what I remember from DJ was the stage 1 and 2, you are no where near stage 2, stage 2 is for the big bore kits pipes and cams.

a 406 is not a big bore, so your still in stage 1, try the DJ146 thats equivelant to a 160 keihin.

right now 170DJ is equivelant to a kehin 190...440 big bores need those not 406.

a DJ 146...aka kehin 160, might even be a lil big. but better then the dj 170 for sure.

In the directions follow for stage 1, not 2. There's all kinds of wrong here but I'm still too hung over from last night to explain. I'd be more worried about his intake and exhaust then bore size. DJ 146 or 160 Keihin without a doubt will be lean for a no airbox lid setup.

[JOHNDOE83]

This will give you som insight http://www.exriders.com/vbb/showthread.php?s=&threadid=441780

the poping and backfiring only comes from the pilot jet.

if its not doing it now then your pilot should be fine.

id say your way to rich up top...hes right a 160 aka dj 146 may be to lean.....read the link see if it helps.

[Jesse400ex]

Well I tinkered with the fuel mixture screw some more and got it running pretty good, but have another question. I drove it pretty hard and on the top end, it seems to run out of power, maybe fuel, because I can feel the power in the midrange and then it drops off. What could that be? I cant imagine it not getting enough fuel.

[Jesse400ex]

Originally posted by JOHNDOE83
This will give you som insight http://www.exriders.com/vbb/showthread.php?s=&threadid=441780

the poping and backfiring only comes from the pilot jet.

if its not doing it now then your pilot should be fine.

id say your way to rich up top...hes right a 160 aka dj 146 may be to lean.....read the link see if it helps.

I read the thread you had posted. It left me a bit confused, If I am at DJ 170 main and its not sputtering in fourth gear that would mean I’m running lean correct?

[Jesse400ex]

Bump

[dalejiw25]

Originally posted by Jesse400ex
I read the thread you had posted. It left me a bit confused, If I am at DJ 170 main and its not sputtering in fourth gear that would mean I’m running lean correct?
Not necessarily true. You could be spot on. Keep upping your main till it does sputter at WOT, Then back er down 1 size and you should be in the ballpark.

[TRXRacer1]

I PM'ed you a bunch of info yesterday, check it out.

[Jesse400ex]

Well I put in a DJ 165 yesterday to see how it would react. Honestly I couldn’t tell a difrence on how it ran, I watched the headers to make sure I didn’t see them glowing and they never did. I rode with a friend yesterday and when he was behind me he said I started smoking and sure enough I was, we switched quads and every time he changed gears and got on it, it would puff a little white smoke, not munch but just a little. So what kind of damage have I done, and what could be causing this?

[Jesse400ex]

bump

[beags86]

is the smoke white/blueish?

if so thats oil, and should be unrelated to jetting/fuel issues.
remember white smoke is oil, black is fuel.

you don't want either, oil means valve seals/rings and fuel means your running rich, not really going to hurt anything, but your not getting the most out of your engine when your super rich and your wasteing money.

[Jesse400ex]

I’m afraid its white not black, but I replaced my valve seals at the same time I put the piston in.