84 200x with a xr200r carb

[grtrat1]

Just got this new carb and the idle still fluctuates and then wont keep an idle.. Anyone know what the problem could be? The only thing I used old was the throttle cable and screw cap..

[torque]

i assume you cleaned the carb. if not the pilot jet could be plugged or partially restricted. another likely cause could be an air leak around the manifold or carb it self. something else you should consider is jet size. did you compare the main and pilot jets sizes from the origional carb, also look at the air screw it may be a completely different profile.

just a few ideas to get ya going

[grtrat1]

Took the new carb off today and set the air screw(I guess) to 2 1/4 turns... Was a pain to start (Had to full choke it) for a few seconds... Tapping the gas it sounded like it was just sucking air for a few seconds then start to respond to the throttle real good... I tinkered with the idle alittle but still wants to idle alittle high then come down.. I sprayed carb cleaner all around, but didnt respond to it...Im alittle disappointed in the carb as I was expecting a "plug in play".. the only difference I see so far is that it now will idle.. The old carb would just shut down after a few seconds..

[muthey]

have you cleaned out the air box and any air flow orifice, sounds like you have something plugging it up, also clean the tank and maybe add an inline filter

[torque]

so it did not idle before the carb change? by adding a used carb you just introduced a whole new set of variables. to give a decent assessment of your problem you need to provide more details. one thing i know for sure this is not a plug and play upgrade. if i were you i would go through the original carb, and put it back on. when you've solved your problem then you will be better equipped to install your up grade.

[Tri-Z Pilot]

I'm willing to bet the xr200 carb is a couple mm bigger and the compression may be different between the 200x and xr200. I know the xr200 runs a hotter cam, but I cant remember if jetting changes are needed between different cam profiles.
You sprayed carb cleaner around the intake area and it did not increase idle (did you hit the head too) thats good, no intake leaks.
Where is the idle mixture screw located? Behind the silde or in front? If behind turning counter-clockwise with add more air leaning your pilot circuit. If in front counter-clockwise will add more fuel. If behind turning it counter-clockwise helped you need to decrease pilot jet size. If in front turning it counter-clockwise helped you need to increase pilot jet size.
Otherwise how does the carb perform? I.E. 1/4 to 1/2 throttle, 1/2 to 3/4 throttle, 3/4 to wide open throttle.
We need a little more info, carb probs are hard to diagnose over the net.

[Tri-Z Pilot]

I just thought of something else to check, perhaps you have a sticking float valve. With the new carb maybe it is idling high due to incorrect pilot size, incorrect idle speed screw adjustment, or your carb slide isn't seatin in the closed position (could be caused by too high of idle speed screw adjustment, or incorrect throttle cable adjustment.My theory is the float bowl fills with gas then it idles high, then when the float bowl runs out of gas your idle drops and the engine tries to die until the float needle becomes unstuck and fills the carb bowl up again. Also check to make sure your petcock filter isn't clogged providing insufficient fuel flow to the carb bowl. Turn off petcock, disconnect fuel line from carb, then turn petcock on to make sure there is adequate fuel flowing. If it just trickles you have a fuel flow prob, if it pours out you should look into the carb.Are you positive ignition and cam timing are correct? Valves adjusted properly?

[torque]

tri-z is right

the xr carb is 2 ml bigger. the cr is close to 10:1, and it runs more of a top end cam. now depending on weather the carb came from a xr200 or an xr200r you could have as many as three different models of carb. pd97a, pd28a or a pd32a. the jetting air screws needle jets are all different. these carbs will work, but you may haave to switch some carbs around. that is why i suggested installing going back to the original carb first

[Tri-Z Pilot]

Yeah I learned earily on you just dont slap a carb on and expect everthing to be peachy.

Hey torque, is the xr200r the on road version? If so I bet that thing is jetted pretty fat.

[torque]

im not sure when i do this upgrade i look the pd32a, off of the xr200. if i remember correctly they usually have 112 main.