02 WR426f idle problems and a little more

i have a 02 WR426F i am in the marine corps and i am from califorina, i had to leave my bike in califorina for the last three years i rode it once march of 2006 i have recently moved to ohio and had my bike shipped out here to ohio.

i put new oil in it, and drained all old gas out and put new gas in it. then i went to start it, i put the choke on and started it on the 3rd kick. i let it run with the choke on for about 30 seconds i turned the choke off and the bike died.

i am postive it is a carb problem, i have played with it a little bit and cn't figure it out. i can start it with the choke on, rev it up a little turn the choke off while reving it and it runs, but as soon as i let go of the throttle it stalls.

for poops and giggles i changed the spark plug and it idled just fine. i rode it for 30 min and all of a sudden it started stalling. my raditor resavor was bubbling. i went to start it and it did not have any compression for about 4 kicks. have no idea what the hell that means.

i let it cool off for about 45 min. i tried starting it for ten min and got nothing, rolled down a steep paved hill to start it nothing tried for another ten min finaly got it started drove it to my barn and it died 10 feet before i wanted to stop.

i am at a loss. i have never had any problems with big blue. i am about to just take it to the dealership and have them look at it.


If you left gas in the carb for three years it's pretty much guaranteed to be crapped up. You'll need to take it apart and clean it at a minimum. As for the compression loss and radiator bubbling it could be a blown head gasket but that's just a guess.

Unless you ran the carb out of gas before you stored the bike I guarantee the gas in the carb about turned to varnish. Sounds like the pilot (slow) jet is clogged at a minimum. Take a carb apart and give it a good cleaning making sure you can pass air through all of the jets. Just spraying them with carb cleaner doesn’t always get them clean. If you ever store it again add some Sea Foam, the stuff works wonders!

Clean the Carburetor making sure every passage is clear.:confused:

Replace radiator fluid and radiator cap.:confused:

after all this is done put air in the tires clean the air filter.:confused:

Now put your helmet on and go for a real ride and stop putting around for half hour at a time:thumbsup: :confused:

Exactly the same problem here...picked up an '02 426f that sat for nearly 3 years. The bike started fine, but would not hold idle. Pull the carb and do a thorough cleaning...pull all the jets (especially pilot and main) and clean, blow air through each passage. Do not use anything (paperclip, etc) to try and clean the jets or passages, you will damage them. If all else fails, replace the pilot and see if that helps.


If... the bike ran fine with the 42 pilot in it, I suspect it may be partially clogged. Cleaning pilots is often pointless as the openinga are so small that even a ever so slight film of varnish affects them. Normall fuel screw setting is between 1.5 and 2.5 turns.

I'd first replace the pilot then do the pilot test:

Fuel screw settings in the 'book' are recommended starting points. Every bike is different, as is the temp and altitude. Set the screw according to this method.

Gently turn the screw all the way in. Now back it out two turns. Start the bike and fully warm it up, go for a 10 minute ride. Set the idle to speed to 1,500~1,800 RPM as best you can (I know, without a tach this is tough, just set it to were it idles relatively smoothly). Once warmed, slow the idle to the lowest possible speed.

*** When turning the fuel screw, keep an accurate 'count' of the amount you are turning it and record it in case you have to reset it for some reason. Makes life easier when you can just set it from notes Vs. going through the procedure again.***

Turn the screw in until the idle becomes rough or the bike stalls.

if it stalled, open the screw about 1/4 more turn. Restart it and slowly screw it in till you can just perceive a change.

If the screw can be turned all the way in and the bike still idles perfectly and does not stall, then you need to go down a size in pilot jet.

Now very slowly, open the fuel screw till the idle is smooth. Blip the throttle, let the bike return to an idle, wait say ten seconds. Confirm it is the same smooth idle.

If the screw has to be opened more than 3 turns to get a smooth idle, you need to go up a size in pilot jet.

If you find it does not stall with the larger jet but has to be open more than three turns with the smaller pilot jet, put the larger one in and set the fuel screw at 1/2 turn.

If the idle speed increased, adjust the idle speed knob to return the bike to a real slow idle speed. You must then re-visit the fuel screw. Keep doing this till the fuel screw is opened just enough to provide a nice steady idle at the lowest possible RPM. Once this is done, increase the idle speed to the normal one for your bike, typically about 1,800 rpm, but go by the spec in your manual.

Additionally, in your colder weather, a larger pilot may be called for.

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