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Looking for some help after my 14 yr old who likes to ride my KDX and had a scary stuck throttle incident. the cable is new and the throttle itself snapped back closed like it should, but the bike kept racing. My son is actually the mechanic of the family, Lol. He figured out that the carb slide is getting stuck when wide open (the throttle never sticks when I ride the bike because I'm slow and really opening the throttle to the point where it sticks). A new slide is good amount of money so I asking whether polishing/sanding down the slide or inside of the carb to make the slide move more freely is recommended. Or should I just buy a new jet needle and slide? thanks.

was he riding thru mud or muddy water? Maybe dirty water got sucked in to the engine due to the intake snorkel having been removed. If so then put it back on. Only other thing it can be is if the air filter had not been recently cleaned and oiled and it let dirt in. There's no reason a slide should stick unless there's a problem with the throttle cable or there is dirt on the slide.

Thanks. The cable and throttle tube were clean. cable is new. He took off the carb and found that when the slider (which was clean) did not move up and down freely when it got near the top. So, the slider moved freely during the first 3/4 of the way open and then gets hung up the rest of the way. He showed me by pushing the slider manual up and down. Is the slider supposed to pop up and down freely from top to bottom? Do carb sliders become warped? Or could the needle jet be slightly bent? Wondering if I take the carb to a machine shop to smooth out the slider and/or the inside of the carb would do the trick or will that ruin the carb?

The slide should move freely from bottom to top....there's usually some play from side to side but so long as it's not too excessive it should be ok. What can happen over time is this excess play can wear the chrome coating off the slide ( check the lower corners for wear ) this can peel the chrome & cause the slide to stick or catch, what I would do is remove the slide & inspect , next reinstall the slide but leave out the needle...check slide motion in the carb , if smooth then inspect the needle ..it may be bent ...if it's good then fit everything back together & inspect again.

Thanks. I'll try it.

fpintauro wrote:Thanks. The cable and throttle tube were clean. cable is new. He took off the carb and found that when the slider (which was clean) did not move up and down freely when it got near the top. So, the slider moved freely during the first 3/4 of the way open and then gets hung up the rest of the way. He showed me by pushing the slider manual up and down. Is the slider supposed to pop up and down freely from top to bottom? Do carb sliders become warped? Or could the needle jet be slightly bent? Wondering if I take the carb to a machine shop to smooth out the slider and/or the inside of the carb would do the trick or will that ruin the carb?

removing more material will make the slide even looser, and may become a problem with jetting (air slipping around it) in the process.

i would search for a new (not used, NEW) carb for the bike. i know it's expensive, but it's a huge improvement over a worn out carb.

New carb and all the parts that have to be bought with it is well over $700. Can't see spending $700 on a bike I paid $1000 for - that ratio is off. Lol. Thanks.

fpintauro wrote:New carb and all the parts that have to be bought with it is well over $700. Can't see spending $700 on a bike I paid $1000 for - that ratio is off. Lol. Thanks.

needing to spend $700.00 on a bike you only paid $1000.00 might be why you only paid $1000.00

fpintauro wrote:New carb and all the parts that have to be bought with it is well over $700. Can't see spending $700 on a bike I paid $1000 for - that ratio is off. Lol. Thanks.

RBdesigns sells carbs for half that!

Other than this carb issue the bike is mint. My son fixed the problem today - apparently the carb, slider, etc. just needed a 3rd round of cleaning. Thanks.

6 Riders wrote:

fpintauro wrote:New carb and all the parts that have to be bought with it is well over $700. Can't see spending $700 on a bike I paid $1000 for - that ratio is off. Lol. Thanks.

RBdesigns sells carbs for half that!

but his carbs don't include slides, and he doesn't offer them on his website either, so he would have had to basically take the cap of his old carb and swap the new one in, keeping his old slide
which in this case, wouldn't have fixed the ailment