Help Fast? Please

[400excaleb]

I put a new dynojet kit in my 2005 400ex and no matter which jet i put in it the plug is dark black. and also i can be just ride smooth or fast and it will just die and wont start back up, but if i wait about 10 sec. it will. Also when im ridin, if it is reved up real high close to the rev limiter, it will spit and sputter until i let back out of it. please help, have big trip planed in the next week or so.

[yellowzo3]

it sounds like you are flooding it out. first make sure your air filter is clean. then start it up and see how bad it is. from there you can decide what size jets you will need with trial and error. you have to put a smaller jet in since it is getting flooded. if you have no idea where to start, go back to the stock size jet and see where you need to go from there. hope this helps.

[racer94]

plug reading tells all.it is too rich.lean it out,cut back the fuel till you get the right plug reading and go from there.

[lghickman21]

well what size jets came with the kit?

[ohsobad_chevy]

Originally posted by racer94
plug reading tells all.it is too rich.lean it out,cut back the fuel till you get the right plug reading and go from there.

Reading a plug is not the best way to determine how the engine is jetted. Some can tell from its reactions and sound, You can make a lean jetted quad foul a plug and turn it black. ;)

[400excaleb]

Originally posted by lghickman21
well what size jets came with the kit?
it came with 134-170 main jets,

[GPracer2500]

Originally posted by 400excaleb
it came with 134-170 main jets,

Be aware that Dynojet's sizing scale is different than Keihin's (OEM jets). The stock K148 is not the same as a DJ148.

[400excaleb]

i fixed some of the problems, now all its doing is popping when reved up high, and after about 10 minutes of nonstop riding it will die and wont start for about 1 min.

[jordan_m6]

ok so what jet are you useing now.

[400excaleb]

Originally posted by jordan_m6
ok so what jet are you useing now.
i got a 140

[armysig]

first off, what is your bike set up?

aftermarket exhaust? any work done to the engine, stock carb? and what is your altatiude (spelling sucks)

It sounds like your to lean.

If you're running an aftermarket exhaust try going higher for the jet. Try the 150 or 155.

Also are you running it with the air lid off?


If you don't have the insturctions I found them for you.



DynoJet instructions (http://www.dynojet.com/pdf/Q107.pdf)

[400exrider707]

Once your plug went black, its not going to change very quickly, if at all now. YOu need a new plug to re-test. I suggest the auto-lite plugs. You can get a pack of two for a 400ex for about $4.

Tell us all of your mods, and we can go from there. Also as mentioned before the jetting numbers are different in the dynojet kit versus the stock Kehein jets. Heres the ever so popular chart.
hole-----Kehein #--- DynoJet #---Mikuni #
0,0570----147,5------136--------127,5
0,0580----150--------138--------129,4
0,0590----152,5----- 140------- 131,3
0,0600----155------- 142--------133,1
0,0610----157,5----- 144------- 135,0
0,0620--- 160------- 146------- 136,9
0,0630--- 162,5----- 148------- 138,8
0,0640--- 165------- 150------- 140,6
0,0650--- 167,5----- 152------- 142,5
0,0660----170------- 154------- 144,4
0,0670--- 172,5------156------ 146,3
0,0680--- 175------- 158------- 148,1
0,0690--- 177,5----- 160------- 150,0
0,0700--- 180------- 162------- 151,9

[400excaleb]

i got full hmf, uni filter