Newbie needs help

[R1 ON ONE]

Hello everyone, I just bought a 02 400ex with some mods to it, 440 big bore kit, k & n air filter, t4 exhaust and some other stuff.I dont really know alot about quads so heres the problem. It will start right up but stall out if you dont give it gas, wont idle, and backfires when you let off the gas and smokes alot. Any help would be greatly appreciated.

[aviator4]

What color is the smoke?

Black means it's rich (which is doubtfull) and white means it's burning oil.

If it won't idle, and it's backfiring, chances are you need to change the jets in the carb, it would help to know whats in there now, but my guess is you need to go up at least two sizes.

[underpowered]

Originally posted by aviator4
What color is the smoke?

Black means it's rich (which is doubtfull) and white means it's burning oil.


close, black is rich, WHITE is moisture, light blue is oil. sounds like a jetting problem. Are you trying to rev it when it is cold. let it warm up a while then try to rev it. most bikes wont rev while cold, my 400ex wont rev at all until you let it warm up a few minutes, hondas are known to be cold natured.

[aviator4]

He said he was a newbie. Since it's a 440 and is air cooled, there shoudn't be any moisture... I was trying to make it a little easier for him to tell, but technically, you're right.

[tater_kamik]

oil doesnt burn white. try pulling out the choke if you havent been. of course, it may have the choke plate pulled out. if this is the case, try pumping the throttle 2-3 times then starting it. also, you may want to adjust your air/fuel screw. you may have two seperate problems. sounds like your carburetor needs to be adjusted. but it is also possible that you need new piston rings. since you do not know much about quads, i suggest you find someone close to you that understands motors and carbs, and have them look at it, having someone right there is a huge help and you can learn a lot!

[R1 ON ONE]

Thanks everybody for your help

[deejayeb]

hey bro..

Im not sure what color the smoke is, but your problem is DEF. with the Carburetor. If you dont know much about bikes, just ask someone you know who does to come adjust your carb for you. If you bought the bike at an elevation thats way different from where you are now, it just needs to be rejetted. However, I dont think that's the entire problem. The Carb Def. needs to be adjusted, so try to get someone to help you out.

Hope this helps man

peace