Jump to content
Sign in to follow this  

'02 xr250 won't idle

Recommended Posts

Hi, looking to buy a 2002 xr250. It will start, but won't idle without opening the throttle. Sounds like a simple enough problem. What should I check, assuming I know nothing about the history of this bike? thanks, and I hope to snag my first dirt bike in 20 years and become a regular on here!

Share this post


Link to post
Share on other sites

Check to make sure that the idle is set correctly.  If you turn it in clockwise it should pick the idle up some.  If that doesn't help, take the carb out and check the pilot jet.  It could be plugged if the bike had set for a while. 

Share this post


Link to post
Share on other sites

+1 on pilot jet. while the pilot jet is the most likely cause a good complete carb scrubbing should be done.

Record what jets are in it and the needle clip position. Some bikes have never been correctly jetted by previous owners.

Clean the air filter, change the oil and adjust the valves to get yourself off to a good start.

Share this post


Link to post
Share on other sites

Thanks, guys! I'll check it out if the seller will stop being flaky. First he said I could see it tonight, then he said he made plans instead. We set a time to see it in the morning, so I'll see if anything works out.

Share this post


Link to post
Share on other sites

Thanks, guys! I'll check it out if the seller will stop being flaky. First he said I could see it tonight, then he said he made plans instead. We set a time to see it in the morning, so I'll see if anything works out.

Probably doesn't really want to part with it. Make sure you get a title. XRs are a valuable commodity these days.

 

New pilot jet or a carb clean and it will probably be much better. 

Share this post


Link to post
Share on other sites

Well, I bought the bike. He did get it started in the driveway before I loaded it up. It took longer to start than it should have, and it wouldn't stay running without throttle.

I took it home and unloaded it, but didn't have time to fiddle with it since I had a honey-do list to take care of. Anyway, I had a chance to take a look at it today. I was going to do a valve check first because the Honda dealer didn't have a carb rebuild kit in stock. I have a pdf copy of the service manual so I was following that. I am mechanically inclined, but I've never done a valve check before. The manual doesn't say to drain the oil first. Of course when I took the crank bolt cover off, oil went everywhere. Once I got the crank rotated and the valve covers off, I couldn't even get my feeler gauges under the adjuster screw. I am hoping I did the adjustments right. I did it so the gauge would slide under, and I could pull it back out with some slight resistance. Is that right?

After I got done with the valves, obviously I had to do an oil change. When I got to the part where I had to put the filter cover back on, one of the bolts almost broke. I had my torque wrench set on 9 ft lbs per manual, and the bolt started to feel weird. I took it back out and luckily it didn't break in the hole. So now I haven't been able to try to start it because I can't put oil in it until I replace the bolt. 

I cleaned the spark arrestor since it was black with carbon. I bought a new plug, but I didn't put it in because I can't find my gap tool. I replaced the fuel filter also (not sure if there's supposed to be one, but there was one on it...looked dirty). 

I think I'm going to try to start it once I get the oil filter bolt fixed and get oil in it. 

Any other suggestions?

Share this post


Link to post
Share on other sites

Haha what happened to taking apart the carb? If you still have issues I suggest going on eBay and finding the sigma6 carb kit for your bike. I bought one when I was having poor throttle response. Woke my xr up!! :p

Share this post


Link to post
Share on other sites

I didn't touch the carb yet because I haven't gotten a rebuild kit yet. I want to go through the carb, but I'm not gonna take it out until I get a kit.

I think the bike has an aftermarket air filter installed (uni?). The foam is red. Would an aftermarket filter like that require a re jet?

Share this post


Link to post
Share on other sites

Its I carb issue just adjust you're idle screw

I don't think adjusting the idle screw is gonna fix a dieing concern. :huh:

If it's been sitting mabey the filter is clogged and starving the engine of air. Take off the filter and see if runs better. I knw uni filters trap dirt really well so it might be just that dirty. Also an aftermarket filter shouldnt make your bike run that bad off the stock jetting. You would notice weird stuff going on when your riding but not that drastic right off idle.

Share this post


Link to post
Share on other sites

I have the carb apart now. The jets look pretty dirty. The jets are a 138 main and a 48 slow. The kit I bought has a 132 main and a 45 slow. Assuming the only mod is a uni filter, which jets should I use? I pulled the plug and it looked rich, but I don't know if that's from normal riding since I haven't been able to ride it yet.

Share this post


Link to post
Share on other sites

Well, here's what I did:

Changed spark plug

adjusted valves (were tight)

Changed oil

Cleaned and oiled air filter

Cleaned fuel strainer screen and replaced petcock o-ring

 

I then tried to start the bike. It would run on full choke, but die on any other setting.

I bought a Moose Racing carb rebuild kit.

 

Replaced main jet and slow jet with stock pieces from the kit

Replaced needle valve with new one and moved clip to 3rd notch per manual (clip was on 2nd notch on the old needle)

Replaced all gaskets, o-rings, etc that came with the kit

Replaced pilot screw, spring, washer, and o-ring and set to 1 3/4 turns out per manual.

Cleaned the body with carb cleaner, and blew everything out with compressed air.

Drained all fuel from fuel tank and will fill with fresh ethanol free gas.

Checked gas tank vent cap 

 

I got the bike completely back together last night, but didn't try to start it since it was 11pm and didn't want to wake neighbors. I can't think of anything else to do. If it won't run now I am going to cry.

Oh, and I didn't have an o-ring between the side plastic and the airbox door (diagram says there's supposed to be one). I bought one from dealer, and I can't get it to stay in the groove. How am I supposed to put it on? Pics anyone?

Share this post


Link to post
Share on other sites

The 132/45 is the stock jetting, generally thought of to be lean. Most 250's run better using 135 or 138 main and 48 pilot.

leave the oring in the sun to warm it up then stretch it out some. If it still pops out try a few small dabs of 3M auto trim adhesive. 

Share this post


Link to post
Share on other sites

I finally got to start the bike last night. I didn't get to play with it much though because it terrified my 2.5 year old son. It's really no louder than my lawn tractor, but he started screaming as soon as it fired up. Oh well, at least I know it runs.

I did fiddle with the idle stop screw some and it didn't seem to have a big effect on the idle speed. I think I need to play with the pilot jet some... Since it's on the engine side of the carb, turning the pilot out should give more gas, right?

Share this post


Link to post
Share on other sites

I think I need to play with the pilot jet some... Since it's on the engine side of the carb, turning the pilot out should give more gas, right?

Right, and I assume you mean the fuel screw. You don't turn the pilot jet for tuning.

Edited by Trailryder42

Share this post


Link to post
Share on other sites

I meant to say pilot screw, not jet. The manual calls it the pilot screw.

The bike starts fairly easily from TDC (2-3 kicks). I'm trying to set the idle now. Manual says 1300 RPM + or - 100. 

Right now I'm on stock jets with clip in 3rd notch on the needle. Pilot screw is 1 3/4 turns out. These are factory settings. So you're supposed to warm the bike up, then use the throttle stop screw to find 1300 rpm. I have a hour/tach meter attached to the plug wire. Problem is, my throttle stop screw doesn't seem to be changing the idle speed. If I try to open the throttle, it will either die right away, rev and die, or rev and hang. 

Help?

Share this post


Link to post
Share on other sites

Try opening the fuel screw/pilot screw to 3 turns and see how it runs.  Follow the link in post #12. 

 

If you are opening the throttle too quick, it will die because it is not a pumper carb and it's not a two-stroke.  That isn't how you ride these bikes in the real world either.

 

By tuning/jetting you can virtually eliminate that bog in real world riding.  This should be checked when the bike is fully warmed up.

 

And forget the factory settings if you want this air-cooled bike to run it's best and coolest.

 

I would go up one size from stock on the main for cooler running at WOT and then forget about that for now.  Work on the pilot circuit (see post #12) and then the needle position.  I would probably go one notch richer on the needle to smooth throttle response.  You should also check the float level.  

Share this post


Link to post
Share on other sites

Thanks, baja. What's the concensus on removing the decompression lever? I've seen some on here say the 250 doesn't need it. What effect would it have on the motor running or starting if it wasn't adjusted right?

Baja, so should I change the slow jet as well as the main?

Share this post


Link to post
Share on other sites

Thanks, baja. What's the concensus on removing the decompression lever? I've seen some on here say the 250 doesn't need it. What effect would it have on the motor running or starting if it wasn't adjusted right?

Baja, so should I change the slow jet as well as the main?

I would say the 400 doesn't need it either but removing it is another issue. Why do you want to change the slow jet? Your posts seemed to indicate it was now running ok at idle, maybe I missed something. Usually when I do rebuild or carb maintenance work I replace it as well.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×