1990 xr200 carb rebuilt, still won't run right

Hello all,

I bought a 1990 xr200r, all original down to the chain, sprockets and tires.  it was not abused or stored improperly.  I changed the oil, rebuilt the shock, and off I went.  It started okay, but had problems idling and mid-range bogging.  I rebuilt the carb with a new pilot and main jet (stock size), new float, set float height, new needle (stock clip position) and generally cleaned the carb very well.  Also put in a new spark plug.  The bike now starts first kick, idles well, and revs out fine.  The problem is in the mid range (1/3-1/2 throttle).  If I hold it at steady RPMS there, it will bog and sputter.  The plug was black, so i assumed rich condition. I dropped the needle one clip, and it got a little better but not much.  I am not sure what to change, and I don't want to change everything at once and get much worse.  Does anyone have advice as to what I can do to remove the mid-range rich condition? Thank you for reading!

did you adjust the fuel screw? probably need to turn it in a tad bit to lean it out but not so much to cause idle issues

I turned it in as far as I could and still get a decent idle.  Still the same problem.  The bike also pops quite a bit on decel if that helps

poping on decal is usually a sign of a lean running engine.... the "O" ring between the carb and the intake boot aswell as the one between the intake and the head in good condtion? you don't by chance have a lower compression piston installed? I did that once. would always run stupid rich but ran diecent so I didn't bother with it.

 

at throttle opening between 1/3-1/2 that is when the transition occours between pilot jet and main. start changing your needle clip position around and see if you can improve the problem

Got the same problem . Should the polit jet have a small o-ring on it ? Found a small piece of rubber at the end of the jet while rebuilding the carby.

What grove should the needle be at?

3 down from the top?

I don't recall if that carb has a removable emulsion tube or not.

I'm thinking that may be your issue.

It has to be super clean and makes a huge difference how it runs in that range.

Certainly replace all 'O' rings.

Do you have an ultrasonic cleaner? If so, take everything apart and leave it in for an hour or so.

Blow it all out really well (careful of high pressure air of course- you can 'inject' whatever you are cleaning with into your skin with it!)

What does the sparking plug look like?

Certainly check for air leaks. I just use carb cleaner when the engine is running- spray at the connection points, the engine speed will change at a leak.

You have replaced everything except the throttle slide and the needle jet. From what you are describing, I suspect the needle jet is worn. I remember seeing a post by Chuck that he replaced his and cleaned up some of his carburetion issues. Think about it, if it is worn, it will let more fuel in. Replacing it, will less fuel in, provided it is indeed worn. The mid range circuit is primarily controlled by the needle jet, needle and throttle slide.

 

16165-446-305 HOLDER, NEEDLE JET

 

 

My .02 worth.

 

Michael

Yes, that jet holder (#13 in the diagram) is also the E-tube. Those little holes add air to fuel, emulsifying fuel with air to start the fuel air mix process. Hugely important!

You can pull it and make sure they are clean (don't poke stuff into them) but probably better to do as suggested and just replace it.

From your description. This seems the likely problem to me. The needle could be worn as suggested also.

Mark

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Edited by lotus54

Thank guys for your info in the right area. Great stuff .

Turns out the the needle c- clip had got stuck in the middle of the two clips that are there to hold the needle down. Prob done on re- assemble . Thank guys.

You have replaced everything except the throttle slide and the needle jet. From what you are describing, I suspect the needle jet is worn. I remember seeing a post by Chuck that he replaced his and cleaned up some of his carburetion issues. Think about it, if it is worn, it will let more fuel in. Replacing it, will less fuel in, provided it is indeed worn. The mid range circuit is primarily controlled by the needle jet, needle and throttle slide.

16165-446-305 HOLDER, NEEDLE JET

My .02 worth.

Michael

I know this thread is old, but how do you replace the needle jet?

It is what the main jet is screwed into. I think you need an 8mm  to remove from the bottom of the carb. 

 

I think you purchased a kit which includes the needle jet, so you should be fine. 

 

It is also referred to as an emulsion tube.

 

It is the "long" tube that screws into the bottom portion of the carburetor, again with the main jet screwed into it, part #13.

 

Michael

Edited by KTM520EXC

Honda calls the emulsion tube a needle jet holder. :facepalm:

 

The needle jet is a light press fit into the carb body. To remove it you must remove the main jet and unscrew the jet holder. Then use the handle of a screwdriver and tap on the needle jet from the top of the carb, it should drop out. The needle and needle jet wear from vibration making the engine run at the transition from idle to the needle, the critical throttle position just off idle from a trailing throttle.

The kit is no longer available for most of the XR200R carbs but the 98-02 version will work (16012-KT0-A10), just avoid the CA version (16012-KT0-L00). (The letter L means Looney, no offense to my Canadian friends.)

 

Post on solving XR200 jetting issues: http://www.thumpertalk.com/topic/974129-99-xr-200r-jetting/?view=findpost&p=10611764

 

Cleaning carb  http://www.thumpertalk.com/forum/showpost.php?p=8896796&postcount=1  

 

PD Carb rebuild video (ignore the decel valve): http://www.thumpertalk.com/topic/1023210-carb-tutorial-coming/#entry10758564

 

Hope this helps

Thanks guys!! I was looking at part #3

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