so many more questions? "400ex Jetting"

[berryj189]

Took my stock jets out of 03 400ex. While researching jet kits, I don't see the actual jet in the kit. I just see the screw with the standard screw driver slot that goes on top of the jet. Is this all that comes in the jet kit? Correct me if im wrong, the jet kit should have the long stem with small holes on the side"AKA main jet".
Also, The kit lacks a pilot jet. Where can i obtain these items???

[honda400ex2003]

pilots need to be purchased seperately aside from the kit. dyno jets have just a round screw in jet with a hex adaptor that it screws into. ill get a pic and post it in a sec to show you the difference. steve

[honda400ex2003]

http://img718.imageshack.us/img718/8771/img0052mb.th.jpg (http://img718.imageshack.us/i/img0052mb.jpg/)
http://img710.imageshack.us/img710/5993/img0050np.th.jpg (http://img710.imageshack.us/i/img0050np.jpg/)
http://img710.imageshack.us/img710/1566/img0051vh.th.jpg (http://img710.imageshack.us/i/img0051vh.jpg/)
http://img534.imageshack.us/img534/4759/img0049pn.th.jpg (http://img534.imageshack.us/i/img0049pn.jpg/)


the dj has the round end the keihin doesnt. also if you have a dj kit it will have a different needle in it also. the keihin mains done have a flat head notch at all. teh pilots will have a notch in them and a series 26 will work to buy them if needed.

Why exactly do you need to replace jets? Did you change something that would require a jetting change?

steve

[berryj189]

added full hmf exhaust
stage 2 hot cam
new piston and bore 85.5mm
k/n air filter

[honda400ex2003]

are you now looking for recommendations? I didnt see a question anywhere or anything insinuating that you were. Did you get the jet style issue figured out? steve

[berryj189]

Yea, got the jet style figured out. Now i'm in a pickle. My header pipe gets red hot so this tell's me she is lean, but my spark plug is black so this tells me it's rich. Ordered a 170 main. it had a 165 on it. I will try the 170 and get back to ya.

[honda400ex2003]

what style is it? your pilot or needle could be rich and your main could be lean. or vice versa. lol steve

[tri5ron]

Steve,
You might want to explain the differences in actual jet sizing between the Kiehens, and the DJ's.

This could also be playing into his frusrations, if he is unaware that they are sized/I.D.'d differently.

[honda400ex2003]

I suppose i can do such a thing. I hope that he read through the chart just to see the diffferences. The dj jets are quite a bit smaller numbering system, than the keihins. The keihins are approximately 1.08-1.09x bigger than the dj system. The dj stuff has an adaptor to make it look almost like the keihin style of stuff also just with the round "jet" ends on it. the needle is a bit thinner also which can be good for some and bad for others. it can make it run richer which is good. especially when running e185 gas or alcohol. I hope that is enough to get you a bit more background on the diffferent styles and how they work. steve

[berryj189]

The stock pilot is in it "38"
The main is a 165. I took the whole main jet apart. 3 different pieces. The bottom which is the end with the number and a screwdriver slot. The middle and the Top or the tube with all the holes in it. So what name brand is the jet with the slot? As for the needle, all i can tell you is it's there. Will that be something i need to change as well?

[honda400ex2003]

The main jet is only the end of the whole brass piece. the rest of it is the housing. you are running a dyno jet setup and will have to go down quite a bit imo. check out the pictures and take a picture of yours so i can see what you have there. at least you have the stock pilot in it at the moment. that is good for now. steve

[honda400ex2003]

http://www.bikebandit.com/houseofmotorcycles/2003-honda-motorcycle-trx400ex-fourtrax-ex-carburetor/o/m2661sch98410


39 is the main jet
24 is the needle housing
25 is the main jet housing

steve

[honda400ex2003]

yours will have a hex style 1/4" adaptor and then will have the round end with the flat head on it. hence the 3 pieces of your assembly instead of only 2 pieces. steve

[berryj189]

OK, I put a 170 main in, cranked it and got it hot. Pulled the plug and it was black. The header pipes were glowing red again. So, is it lean or rich? what is next?

[bherriman]

How are you doing your plug readings? after it just sits and idles or after a correctly done plug chop? If you are just letting the bike sit there and idle its gonna get hot. If you are riding the bike and the pipe is still turning red I'm gonna guess you are rich. 9 times out of ten when people say their header is turning red they just have it idling, and this indicates a lean condition, however the other 1 out of 10 times people are actually riding the bike under load and the header turns red, this can be a rich condtion. There is so much extra fuel being introduced into the combustion chamber that it overpowers the oxygen and not all of the fuel gets burnt. All that "leftover" fuel gets pushed into he exhaust were it combines with enough exygen for the fire from inside the combustion chamber to chase it down into the exhuast, creating high egt's.

[bherriman]

Also from reading the earlier post I am guessing you have dynojet main which you said is a 170. That like a 190 keihin. I would guess you need to be around a 154-160 Dynojet or a 170-178 keihin, but thats just my guess

[berryj189]

Problem solved. Thanks for the help. I ended up putting a 170 main and a 40 pilot. Throttle response is awesome from the bottom to the top now. Headers still glow red just a little when it is at idol, but when i ride, they cool down.

[CJM]

Its still lean if the headers are glowing, try bumping up one side on the main.

[416racer]

I dont think the main jet would cause it to be lean at idol.