83 XL600R carb issue... Help!

I posted this question awhile back and received some good feed back. but im still having issues after checking what some of the other guys said to check. now im at wits end... i have a 1983 honda XL600R. heres the issue... the bike has a hanging throttle. not all the time either. once bike is running and you start playing with the throttle it tends to hang at higher rpms. once you crank the throttle the bike will come back down to normal idle then if you play with throttle again it will stay at a high rev again. i have- checked all cables and are nice and free. throttle itself has good movement as well. i have pulled carbs off twice now and gone through them top to bottom. slides are moving freely. i started bike with rear of carbs exposed so when i ran the bike in garage i could look into them. when the bike is at the hanging throttle stage both slides are down where they should be at idle speed with no twist on throttle. but yet the engine still is at a high rev stage. what gives? how is it getting fuel to have such a high rev on engine with slides all the way closed? yet then if you crank throttle and let off, the engine will go down to normal idle until you twist throttle again. Ugh!!! air screw is set to spec. choke is working properly. slides are not sticking. im assuming the issue has to be in the primary carb. thoughts... is my float setting off, needle seat worn, needles look good by the way. any help would be greatly appreciated being it is hard to ride the bike because its difficult to ride around when the throttle is what drives the bike pretty much and the hanging issue could send me into a tree or car.... thanks again for any help or thoughts anyone might have on this issue....

What occured to start this hanging throttle problem??.,ie ,,had you done anything to the bike mechanically before it began or did it just suddenly start.??

Have you tried running the bike with the fuel tank off to see if it is a cable crushing type issue??,,ie fill the carb with fuel,,remove the tank,,start the bike and jiggle the cables to see if the jiggling has an effect..

Do you have a 5mm gap between the throttle grip and the end of the handlebar.??

Do you have a couple of mm gap between the throttle grip and the throttle housing??

Have you sprayed around the carb intake manifold with Ether or the like to see if it has an air leak at the intake??,..

Edited by Horri

Horri, i have tried all the above... ive done everything imaginable to fix the issue. the throttle has been this way since i bought the bike last year. just have delt with it. the things that have been done to it since ive owned it is, new rings, cam chain, valves redone, and a new clutch... thanks for the reply...

Take a close look at the air cut off valve?

thanks winginit. i was just reading through my shop manual and saw that was something i did not check the two times i have pulled carbs apart. will check it tonight....

might be that some of the internals of the carb where the needles run through are just plain old and flogged out..There's a brass type fitting in the center of the actual carb body where the needle runs through that may be a possible problem..I'll look up the part numbers for it in both carbs and get back to you ,,No guarantee it's the issue,,just a maybe,,might as well replace them if you have the carb apart to the degree you have to do the aircutt valve....

Go to the carb fiche,,


Part is marked with the numbers 3 over a 12..Don't know if you have to buy new needles with it..The part itself is a small brass tube about 5mm long which fits in the center of the carb body which the needle moves up and down through..

Just a guess really that,,I don't know whether it'd really be the culprit....one in each carb as far as I remember..

Edited by Horri

Well i want to thank you guys for your help but after another night in garage with carbs off and torn completely apart this time to check and set floats to the correct spec and to look at the air cut off valve it was to no preveal, Ugh!!! just cant understand what the issue is. o until i find a set of different carbs to try im letting it sit. that is unless i get tired of looking at it and start stripping it down and selling it part by part haha.... thanks again guys..... maybe i can brainstorm some more or if anyone else can think of anything else it might be....

I have an '87 XL600R (CA version if that makes any difference) in otherwise great shape, but with the exact same problem! I've gone through the same troubleshooting too. Been this way for years, but I was back to looking at it again tonight. It always sort of drove me crazy, but I guess I learned to live with it. Now I'm getting ready to sell the bike and don't want to get beat down for a stupid issue like this though. Any new suggestions anyone?

Not from me..If you've checked all of the above (the air leak possibility would be my main target) then I don't know..As a test for my two picks of position for the air leak to occur I'd replace the gaskets between the carb intake manifold and head and the ones on top of the carbs. If that doesn't cure it then I'd possibly be suspecting some sort of valve problem or maybe worn slides..the worn slides being least likely but you never know sometimes with hanging idle issues.,,My last one wasn't solved until I replaced the entire carb..that sorted it once and for all..

Edited by Horri

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