On the contrary, ONEBAD440; adding fresh fuel doesn't eliminate problems with condensation in the fuel system.

Since water is heavier (more dense) than gasoline, water settles to the bottom of the fuel tank and collects in the float bowl of the carburetor.

The main jet is the lowest (altitude-wise) in the carburetor; can suck up condensation (water) when the pilot circuit works fine.

RobRider asks for the solution: Draining the system (shut off tank petcock; drain carburetor float bowl with dump tube; drain tank if necessary using RESERVE petcock position. Add a liitle "Dry Gas" ("Heet" or similar product) to the tank upon refilling; indeed, you may be able to solve the condensation problem merely by adding the treatment fluid alone to the tank.

Good luck, RobRider!

Diogenes

 

Hey guys. I had an XR-400 that would act similiar. It was jetted waaaaaaaaaaaay to rich. And the floats were waaaaaaaay to high. When you got the bike jumping around, it would stall because the float would bounce in all that fuel and push it into the chamber. And because it was jetted so rich, if you let it just die before it was warmed up completely, it would wet the cylinder down. You would have to pull the plug, and use the air compressor to blow it off. Then put the blower into the plug hole and blow out the cyl. It would usually fire right up after that. When it would die like that, could you pull it off? My Xr wouldnt'even start that way until I blew out the cyl.

Good luck
Gary

 

Hey I got a 2000 400ex and mine is smoking. The whole reason I got a 4-stroke is becuase of low maitinence. I kept a good plug(NGK) and good oil(GN4) and i changed my oil filter. I also have a uni air filter. In your case i think it might be your carbuerator, take it off and clean it.If your promblem persists write to dirtwheels. Hope you fix it !!!! www.clryders.net

 

Hi, I don't claim to be an ATV expert, but here's my input. I have a Recon, which was behaving similuarly to what your describing. My problem was that their was a tiny piece of rubber stuck in the float bowl that worked it's way into the main jet after I had road around for about an hour. All I had to do was take the main jet out, blow the piece of rubber out, and re-install the jet. It ran fine for about 3 months, and then happened again. I did the same thing and it's been working great for about a year now. I talked to the Honda corperation, and they said that the rubber was probably from the manufacturing process when they sealed something. So just incase I installed an inline fuel filter from my Honda dealer. That seemed to stop what ever was giving off the rubber. It's just my input remember, so no bashing me if I'm wayyyy off, but it seemed to work for my recon!

 

2 things
1. check the air hose from the gas cap the end may be clogged
2.check the gap on the plug

just a suggestion

 

hey ralph2000, the reason yours is smoking is because it wasnt broken it properly. to do it you need to run it at half throttle for 10 mins., let cool do the same for 20min, and then for 30. change the oil and top off the gas. run it at under half throttle for the first tank of gas and you are set, no smoking, better power.

 

Thanks for the science lesson Diogenes.
I also wish you luck RobRider.

 

RideRed04 - either that, or it could be that he's running thin oil (10w-40) and its breaking down. Best fix for that (from Gabe) is to put Mobil 1 20w-50 oil in. Worked for lots of people here on the forum.

ogre

 

robrider,make sure you have no air leaks between carb and intake or anywhere else for that matter.usually a backfire is a lean condition.

 

Are you sure it is not a spark plug prob?? I have seen plugs that will spark when checked outside of the cylinder but will never start the engine. My own 400 did this the first night I owned it. If you didnt actually try another plug I would try it first. Ignore all this if you already did