Hey guys,

I got a 2003 400ex that has been sitting for two to three weeks. It was running great when i parked it. I know the gas has turned bad and probably gummed up my carb. My question is how hard is it to get the carb of too service it? Also I have been doing some searches and read that a number 42 pilot jet would erraticate the need of using the choke? Any way the 400 has a pipe and K&N air filter, not sure what size the jets are in it now but i know it has been jetted. I am picking up the shop manual today after work to help me. Any suggestions to make this less intimidating would be greatly appreciated.

Thanks Josh

 

Take all the plastic off take the airbox out, intake from airbox to carb. off, gas tank off, it's easier for me to take the throttle cable off at the thumb throttle loosen the hose clamp on the carb. side of intake to jug pull the carb. off boot wiggle it out from airbox area. Flip it upside down take the bowl off remove the recessed pilot and the main jet, pull the pin out that holds the float on pull the needle valve and float out, clean everything with carb. cleaner and a piece of wire reinstall, good to go.

 

2-3 weeks gas should be ok.pull the drain plug bolt off the bottom of carb its a 17 mm bolt and you can see if its gummed up.

 

The carb is fairly simple to go through. Just take your time and and have a clean surface to work on.

 

If it has only sat for a couple of weeks, likely only the gas in the float bowl has gone bad.

Gas goes stale fastest in small quantites, when exposed to the air (like in the float bowl).

I'd try draining the gas out of the carb, turn the gas on with the drain open for a second to flush anything left out, and close the drain.

Then try starting it. If that doesn't do it, check or replace the spark plug. Attempting to start it with stale gas can foul the plug.

If that fails, then I'd say it is time to pull the carb and spray out all the jets and passages in the throat with a good carb cleaner.


Next time when you put the quad away, shut the gas off and run the carb dry, or drain it when you park it.

 

i pulled the carb off yesterday and sprayed out the bowl and the jets, put everything back together tried to start it and no go, i checked the spark plug and it was black, so i wiped it off and put it back in sprayed some starter fluid into the intake of the carb and it fired up only to burn off the starter fluid and then die. I also drained the gas that was in the tank and put fresh gas in it. im lost, gas is getting there but thats about it. thanks for the help i really want to figure this out.

 

So is gas getting to the float bowl? (Open the drain).

If not, there is a fine screen inside the tank. To clean it you remove the screws around the petcock. The other possibility is the float is hanging up.

If there is gas in the float bowl but it isn't getting to the engine, you still have a clogged idle passage. In that case pull the carb again and blast out every jet, remove them and blast out every passage inside the throat and in the float bowl.

You might also stick a new plug in it. It would be interesting to see if it also turns black. Does the machine burn oil?

 

you need to see what jets are in in next time when you take it apart...sounds like it is running rich.

 

thanks again, no the bike doesnt burn oil at all that i am aware of, never seen any smoke and i change the oil when needs it. i will change the spark plug and find out what jets are in it. by the way it was running great when the weather was warmer now that it is cold i get this. not nsure if it is releveant. thanks again.

 

havent had a chance to take apart the carb again, but had a question about the air filter. I have the k&n, it was in the bike when i got it. This is the second time my bike acted like this the first time it was dirt in the carb and now this which i am sure is the same thing. I am about to order another air filter but are unsure what to get and wheter or not i will have to rejet going to a different filter, what are you guys running in your 400's?

thanks again.