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Dirt bike reving supper high

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Just got 1981xr200r from a guy for $100 and for some reason it just won't idle. I cleaned out the carb and the jets with gas and an air compressor fresh gas.

 

Starts right up no problem with choke revs super high. I took off the cable from the throttle and it some what idles ok with it but I can be sure because my hand couldn't hold the cable steady. I was thinking maybe it was the cable that made it do that because the plastic covering it was all chewed up and it was shorter then the oem is so I ordered a new cable for it I installed it and still rev super high. I should of asked before just buying part though. I also have been looking for the factory carb setting but just don't seem to find them. I know it's out there but just don't know where exactly to look.

 

If you have any suggestions of what the issue is if it's not the carb setting or the throttle cable then please let me know.

I'm new to dirt bikes and really wanna learn. Could of gotten a new bike but then wouldn't have fun learning

Thanks for the help in advance

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I learned to wheelie on an XR200 as a kid.  It's been forever since I've seen one.  But i found the chart below in another thread.  There should be a screw for adjusting the idle on the carb as well.  You might want to try backing that way out.  To rule out the throttle cable / throttle assembly just disconnect it until you can get it to idle right.

 

Year/model ..... Carb model. main.. pilot .... clip ... initial mixture…..

79 XR185……... PD31A … 115 …. na ….. 4th ….  2 1/4 turns out…

80-84 XR200….. PD32A … 102 ….35 …... 3rd … 1 3/4 turns out…May be press in pilot.

81-83 XR200R .. PD28A …. 138 ... 38 …... 4th .… 2 1/2 turns out.…35P in ‘82

83-84 XL200R …PD61A … 100 …. na ….. 3rd …. 1 1/4 turns out…

86-87 TLR200 ... PD07A …... 92 .... 38 ...... 3rd …. 1 3/4 turns out…

86 XR200R ........ PD97A …. 112 .... 38 ...... 2nd … 1 1/8 turns out…

87+ XR200R ...... PD97A … 110 ….. 38 ..... 3rd …. 1 1/8 turns out….

88+ CA XR200R  PD97B … 102 ..... 35 ...... 3rd …. 1 7/8 turns out….

Edited by Doc_d

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Maybe your slide is sticking or not returning to fully closed. Sometimes the throttle cable can get smashed and it won't return all the way. Also check you idle adjust screw.

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Ok what about the float screw does that play a role in the high rev? And I'm using all original jets clean and all

Idle screw is all the way out(open)

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Hi Mario:

Your bike has an idle circuit (pilot jet and air screw, and mixture enrichener/choke) . The idle circuit has it's own separate small venturi that only operates when the main throttle is closed as much as possible.   If you're trying to set the idle by holding the slide slightly up, that won't work.

For example if your cable is pulling on the main throttle and the slide is held slightly up, the bike is revving on the main thottle (just as if you were twisting the throttle grip) and the idle circuit won't work.   Try loosening the cable so it is slack and the throttle is closed (the slide is all the way down).  If the bike idles too slow adjust the main throttle idle adjustment on the throttle bellcrank so the main throttle is open slightly and then adjust the airscrew for the smoothest idle.

The idle sometimes has to be set by the idle adjustment so the main throttle is very slightly opened but there should be no tension on the throttle cable.  The proper idle setting is with the main throttle shut as much as possible.

Just guesses but maybe that will help.

patuca

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Stick your finger into the inlet side of the carburetor and see if the slide is lowering all the way down.  If not, it's probably a cable problem unless your slide has a burr on it hanging it up.  In that case, lightly buff the slide with 400 grit sandpaper until it seats all the way.  Then report back to us.

 

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So I did what you said and didn't work. I had order a new carb the other day just incase. Installed it and it the same thing. I disassembled the throttle from the throttle on the handle bars and it idled some what fine( couldn't hold the cable steady) I'm not understanding. Would it be the throttle at the bar?? Looks find and twist fine. It's a new cable from Honda dealer.

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With the cable disconnected you shouldn't have to "hold the cable steady" to get it to idle.  Set the cable down and adjust the idle speed screw on the carb until it idles.  Once you have the bike idling correctly with the cable disconnected, then determine what the problem is with the throttle/throttle cable.  I'm not familiar with that bike's setup but there is probably a cable adjuster in there somewhere that needs to be adjusted.  But don't even mess with the cable / throttle until the bike idles perfectly with the cable disconnected otherwise you are fighting too many variables at once.

Doc

Edited by Doc_d

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Let us know how that goes.  Once you have the bike idling without the cable hooked up and without touching the cable you've solved half the problem.

 

The second part of the problem is why is the throttle cable pulling on the slide when the throttle is sitting in it's resting position?  The throttle/throttle cable shouldn't be pulling on the carb slide at all when the throttle it at it's resting position.  The throttle/throttle cable is never used to maintain idle.  That's what the idle adjustment screw does.  My best guess is that the throttle cable adjuster is simply misadjusted making to cable too tight which causes it to hold the slide slightly open when the throttle is at it's resting position.

I just dug up a picture of your bike and it looks like the cable adjuster is right where the cable meets the throttle.  There is probably a knurled metal ring.  Turn this metal ring in (as if you are screwing it into the throttle housing) to create more slack in the cable.  I'd just turn it all the way in initially to see if that solves your problem.  If it does, then you'll probably  have too much free play (slop) in the throttle and you can turn that ring back out until you take most of that free play out.   But don't turn it out so far that all the free play is removed because then it'll be pulling slightly on the slide again.  Once you have it adjusted and idling correctly, turn the bars fully to the left and to the right and make sure the idle doesn't change.  If it does, you need to add a little more free play in with that cable adjuster ring to account for turning the bars taking up some of the cable slack.

 

Good luck.  Let us know how it goes.

Doc

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Right now I will take off the cable from the throttle assembly and get it to idle. I will try it with both new and old carb.
2 questions
1. What if it goes back to doing the same after I've made it idle alone and then I hook up the throttle?

2. Mind you I have a new carb preset what if I can't get either carb set for the bike to idle

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Is the carburetor slide seated all the way down at zero throttle, Mario?  There's no way the bike can rev that high unless the round slide is being held up somehow. Where else would the air come from?    Pull the carb and attach a pic looking down the intake side toward the cylinder so we can see the slide position  with the cable attached.  And I'm not talking about the choke butterfly being open or closed but the brass cylindrical slide behind it.  

And another thing, fire up the engine and smother it by holding a rag over the intake side of the carb.  It should die from air starvation almost immediately.  If not, you got an air leak pulling from the intake boot or magneto side crankshaft seal maybe.  Go see if you can smother the engine first.

Edited by Jimmy Pascol

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My '83 had an issue after I replaced the throttle cable. It could be your cable is pinched somewhere and it's not letting it return correctly.

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