400ex jetting

[bowtech99]

i have a 2002 400ex ( just bought it ), it was stock when i got it. i have just installed a rev box, t4 slip on and uni filter......just trying to figure out what jet to use. had a friend w/same quad said he used a 162.....tried that and it would not run...tried 160 still would not run....started to do some checking and it sound like i need alot smaller. was wondering if anyone had any ideas?

[tooanxiousii]

It doesn't sound like it in your jets have you started after you put the rev box in?

[Halter]

I thought jets wise...if u had the wrong jet in it would make it run like sh it.....but it would atleast still run...

[tooanxiousii]

Thats what I'm saying you have something else wrong

[bowtech99]

i did not try it w/just the rev. box.....with the bigger jets in it would only run w/choke on, then it would just quit on its own and would only restart if i held the throttle wide open

[tooanxiousii]

First of all the 400ex does not need the chock to start you just hit the gas a few times and hit the starter if you use the chock you will flood it out and you would run ... sounds like you already did that thats why it it will only try to start with WOT take you spark plug out and clean it and try again with out the chock...

[bowtech99]

which jet do you advise...the 162,160 or stock 148? those are the jets i have but if you think they are wrong i will get a different jet size

[tooanxiousii]

Both the 160 and the 162 should be fine go buy a new spark plug and try it then remember just hit the gas about 3 or 4 times before starting after it's running just work the gas til it warms up

[bowtech99]

thanks for all the help!!!! 1 last question for now, i have been reading alot about moving the needle...do you think i need to also do that?

[tooanxiousii]

no it should be just fine ... Let me how it runs !! where do you live in Michigan?

[bowtech99]

i live in lambertville......if you live close shoot me an e-mail we are always looking for new people to ride with.....

[tooanxiousii]

I live south of Detroit ... Did you get it running?

[bowtech99]

not yet, i ordered a moose jet kit for it. my friend had a 400ex that he used the same pipe, rev box and air filter ad he used this kit so i am going to give it a try....ill get back w/you when its running

[tooanxiousii]

k

[bowtech99]

finally got the dynojet kit installed.....runs like a raped ape but when i let off the throttle quick and pull in the clutch it will want to stall out...ever heard of this, also now with the ign. off i now get alotof fuel pouring out the hose on the ground

[tooanxiousii]

sounds like your float is sticking

[h400ext]

i drag my 400ex and i have this problem with bogging down really bad off the line in 2nd. i have a stage one hot cam white bros exhaust,whats wrong

[tooanxiousii]

How hard do you launch in 2nd .. What gearing do you have...

[bowtech99]

yep got it figured out.....when i took the bowl off everything flew apart and when i put it together i put it back together backwards...lol. once i got it together correctly i have no problems and cant believe the results.....its like a whole different quad

[tooanxiousii]

Glad to hear that!!! Whats your 400ex look like?

[bowtech99]

its yellow and stock looking other than the pipe.....