w.b. and jet kit help

[exrider505]

I have 2002 400ex stock. Putting on a white brothers pro-mega full system. And a dyno jet kit. Any tips on what to set the pilot to and what not? The header is a pain to take off, am i doing something wrong? What all do you have to remove to get the header off? Anything helps.

[4Hundy2001]

If you are going to go through all the work to put on a full system and rejet. You should probably put on a K/N Air Filter also. It will help proformance with the bigger jet kit. Also if you plan on getting a K/N later you will have to rejet again. So if possible get one now.

As far as putting on the Jet kit its not real hard. just follow the instructions and you won't have any problems. It hard to tell you what jet to use it varies from quad to quad. Elevation is a factor any other mods will also make a difference. The Jet kit should have a Jet the recommend starting with.

To replace the Exhaust system is a breeze just rip it off and put the new one on. It that simple. It is kinda a puzzle to get the head pipe out of the tight area just work with it and it will slide out.

Good luck hope you enjoy the pipe.

[exrider505]

thanks for the help. i probley wont get the k&n bc it came with a wb porwerfilter, is that filter any good?

[J25]

i put a 160 in with k and n and lid on, 165 w/o the lid and k and n, and i didnt change the pilot, but if u were to change it you would probably want to put in a 42 pilot, the header shouldnt be to hard to get out, jus un blot the silencer n take it off first and then take the bolt of the headd pipe and slide the header out, if you still cant get it out, unbolt the oil tank and move it back a lil



Hope this helps

[kenny]

throw the jet kit away.main needle keep stock.start with a 160 main jet ,see what your plug looks like.if you want to change your pilot you can go from a 42 to a 45 without problems.bike would probably start easier also. jetting is a practice.knid of hit and miss.you will need to know how to properly read your plug and listen to the engine to verify proper tuning-jetting adjustments.did you get your head pipe off yet . what seems to be the problem. be careful routing your stck clutch cable it is short and gets in the way easily.you may want to order a longer cable from terrycable.com.if needed good luck.

[exrider505]

ok got the head pipe off. and the whole pipe on but now i have another problem the plates that you bolt the head pipe to the head with, got the first one on no problem the other is about half a centimeter off so i cant get it to slide over the bolts, i tried taking the first one off and doing it again but no good.

[kenny]

try to slide collectors on as even as poss over both studs.flip the collars 180 also.if it wont happen you may need to dremel a bit on both sides for clearance.make sure the muffler is not attatched and mount is loose

[exrider505]

it just needed a light tap with the hammer. So the pipe is on and ready to go. Now the jet kit. I might let the local shop do it. Will it hurt it to run it with stock jetting?

[ewalker302]

You should do the jetting yourself, If you can install the exhaust, the jetting should be no problem & the dealer will charge you way more than it's worth.
Start here
http://www.exriders.com/techarticles/jetting.html

Then if you need to, just search this forum for (jetting instructions), or something like that if you need details.

If you run your bike without rejetting you will be running lean/hot this will be bad for the engine.

The jet sizes listed in the above posts are for keihin main jets.

You said you have a Dynojet kit.
The jet #s are different.

Your (DJ)146 is 1 size larger than the 148 Keihin stock jet.

I use the (DJ)146 main with the (DJ)needle, clip 1 position (richer/lower) on the needle. My 400 is mostly stock-- lid on, pipe, filter, degree key.

If you are running with the lid off or at a high elevation you may need to go up to the next larger main in the kit.

After you get the correct main installed you can fine tune w/ the air/fuel screw to get it dialed in.

:bandit: