Hey guys, I'm trying to chase down this carb issue.. I picked up an XR 80 for my kids to ride and it would hardly run, when I got it home I took the carb off and cleaned it out, it was pretty gunky... Got it all back together and it runs better, but I can run the air screw all the way in and it still runs, I'm thinking it's drawing air from someplace else..Also, the choke doesn't really seem to make a difference weather it's on or off..

Any Ideas??

I had an XR80 as my first bike, honestly i remember the choke didnt really change much, if anything it will just sputter when you try to rev it out with the choke on. I dont know how how old the bike is but the only real places it could leak before the air screw is the rubber grommet that goes to the engine, its not dry rotted is it?. It might just not be that sensitive, those XR80's run good no matter what. The only problem I ever had was metallic buildup in the magneto cover that caused a misfire.

first off..to check and see if it's drawing air elsewhere..just like a car..fire it up and spray some starting fluid around intake boot...second..airscrew is for idle only..0-1/8 throttle, I have to ask..did you take all 3 jets out and clean them?? also..the needle and seat can be worn enough that enough fuel gets by under suction and pretty much does away with idle circuit, Improperly adjusted throttle cable?? Other than that did you check your float needle for cracks and dry rotting? I been building these things for 20 years now and those are the most problems I come across..

HMMMMM, it does seem to misfire as well I was thinking it seemed electrical.... What did you do to fix the mag, just a cleaning??

first off..to check and see if it's drawing air elsewhere..just like a car..fire it up and spray some starting fluid around intake boot...second..airscrew is for idle only..0-1/8 throttle, I have to ask..did you take all 3 jets out and clean them?? also..the needle and seat can be worn enough that enough fuel gets by under suction and pretty much does away with idle circuit, Improperly adjusted throttle cable?? Other than that did you check your float needle for cracks and dry rotting? I been building these things for 20 years now and those are the most problems I come across..

Funny, I never thought to spray around the carb, but that's the first thing I would have done on a car.. I guess it's just been so long since I wrenched n a bike I'm a little out of my element :yes::D

The floats are brass, but they look to me like they're set to high.. Do you know what the spec for the float level??

Any Idea where I might find a free online shop Manuel for this thing?? I was lucky enough to find one for my YZ 250 :thumbsup:

Oh, and I should have mentioned, it's a 2001 XR, but I think they're all the same...

Thanks guys for the fast responses :beers:

Hey guys, I'm trying to chase down this carb issue.. I picked up an XR 80 for my kids to ride and it would hardly run, when I got it home I took the carb off and cleaned it out, it was pretty gunky... Got it all back together and it runs better, but I can run the air screw all the way in and it still runs, I'm thinking it's drawing air from someplace else..Also, the choke doesn't really seem to make a difference weather it's on or off..

Any Ideas??

Just went through this with a friends little 125 yamaha. He cleaned the card or so he thought. He was so excited for his kid he rushed through it and half$%^&* it. As said, look for a leak and if not reclean carb. New plug might help. Those things are fun to work on.

When i had a misfire, I basically just sprayed carb cleaner with the straw on to blast every little part inside the magneto.

Funny, I never thought to spray around the carb, but that's the first thing I would have done on a car.. I guess it's just been so long since I wrenched n a bike I'm a little out of my element :yes::D

The floats are brass, but they look to me like they're set to high.. Do you know what the spec for the float level??

Any Idea where I might find a free online shop Manuel for this thing?? I was lucky enough to find one for my YZ 250 :thumbsup:

Oh, and I should have mentioned, it's a 2001 XR, but I think they're all the same...

Thanks guys for the fast responses :beers:

Couple of places..www.scribd.com, www.mrcycles.com, people on forums like bansheehq, thumpertalk are always helpful also..some dealerships list them online you just have to FIND that dealer..:confused:

I'm a member over on CRFsonly.com

Granted it's for CRF's Only....but there are super smart guys over there. They have a "General Discussion" area that you could post your question and they will help yah. Just another option for yah. Good luck. :)

Besides pulling the jets to clean them out you should also blast carb cleaner in all the holes and passages in the carb followed with a shot from the blow gun. It sounds to me like you just didn't clean the carb correctly.

I agree with 67Shovel...If you can get access to this I would go get some..I don't know the name of it but it is sold at commercial HVAC supply houses..It's aluminum coil cleaner..it's an acid like chemical that boils dirt and debris from aluminum..It's biodegradable, and don't get it on your driveway...you can mix it to the desired strength you feel you need. I usually mix mine in an old coffee can an drop carb in for about 10 min. max and rinse with water...don't leave in there too long..I've been told it will desolve the aluminum if left for hours or more!! I just went to look..It's called Virginia Alki foam...works great boiling them carbs out...aluminum radiators too!!..What ever you do, Please don't push wires or anything through the ports that will scratch and score the jet bores...But the alki is what I use, works good, I can clean many carbs with it alot cheaper than buying a bunch of carb cleaner spray...:yes:

I agree with 67Shovel...If you can get access to this I would go get some..I don't know the name of it but it is sold at commercial HVAC supply houses..It's aluminum coil cleaner..it's an acid like chemical that boils dirt and debris from aluminum..It's biodegradable, and don't get it on your driveway...you can mix it to the desired strength you feel you need. I usually mix mine in an old coffee can an drop carb in for about 10 min. max and rinse with water...don't leave in there too long..I've been told it will desolve the aluminum if left for hours or more!! I just went to look..It's called Virginia Alki foam...works great boiling them carbs out...aluminum radiators too!!..What ever you do, Please don't push wires or anything through the ports that will scratch and score the jet bores...But the alki is what I use, works good, I can clean many carbs with it alot cheaper than buying a bunch of carb cleaner spray...:yes:
I have a good friend that owns a HVAC business, I'll give him a call..

Does it also take forever to rev down?

What was the idle RPM during pilot screw adj?

It runs OK, bt out of nowhere it won't idle and will dye.. It's also kracking up on the top end, but I have yet to even look at the plug.. This bike is going to need some TLC, but it should be a lot of fun for the boys.. Maybe next winter I'll have it bored out and some new rings are prolly in order, it doesn't have a lot of compression and it's smoaking a bit..

I hope to have some time to play with it this weekend, but we'll see..

Thanks for the reply's, keep them coming :thumbsup: