200x motor revs on its own.

[Stephon_xr500]

Well I picked up a 1983 200x on Thursday I traded it for a mossburg 22 that I had picked up in September in trade for a 1983 klt 200 that I had picked up for $85.



I got it running last night after cleaning the carb, changing the stator out and the spark advansor. But it runs kinda funny, after running for about 3 seconds it starts to rev higher almost like it was at 1/4 throttle. When this happens the throttle is not pressed at all. I have checked and the cable is not catching or keeping the slide open. I saw my friends 200x do something similar before but it had to do with the cable routing after he installed a front number plate, unfortunately this is not the case with mine. I'm kinda thinking it could be an air leak but I haven't had time to spray the motor while running with staring fluid. The motor also smokes I'm assuming valve seals because it still starts and runs so the rings should be ok.

It's been a while since I had a 200x so any extra thoughts or opinions would be helpful. I'm trying to build this trike up so my 12 year old can start racing MX with us here in Arizona.

[YTZ drew]

Sounds like an air leak, a worn slide/carb body, or play/loose springs in the advance unit. Those are pretty much the big 3 causes, in order of likelihood. Spray some WD40 around the intake, and see if it changes. Keep us posted!

[Mickey Dunlap]

I agree, it sounds like a air leak. Could be just the o-ring between the carb and the intake since you just had it off, or the manifold it's self could be dry rotted and a small crack in it.

[Stephon_xr500]

Thanks guys, that should get me looking in the right direction. I felt like it was a huge victory just getting it running! It sounds good with the super trap pipe

[rdonald1979]

Nice grab for 85 bucks really.

[mohadib]

I experienced this on an old suzuki quad racer. Turns out the previous owner tried to put in a new crank seal ( the one on the flywheel side ). He didnt seat it all the way so air was sucking in there. It would rev high at idle, then bog out like it was running out of gas when I rode it.

[Chopsaw]

If you dont install the slide correctly it will hang open .

[Stephon_xr500]

The carb slide is not catching at all. I can hear it sliding and snapping closed.

[yaegerb]

Air leak or lean jetting

[Stephon_xr500]

I did introduce k&n air filter into the mix with the super trap exhaust maybe it's breathing to good.

[JustEnough]

The slide will float if the spring is not long enough. Is there a chance that you put a different spring in when you cleaned the carb?

[rdonald1979]

Change out that old o ring on the intake.

[Stephon_xr500]

I installed the spring that was in the carb when I got the trike, I will be taking it apart again this afternoon to inspect the spring, intake orings, and jetting later on today.

[yaegerb]

Start it and spray carb cleaner around all fitting to make sure you have an air leak before you start dismantling everything again.

[fabiodriven]

I experienced this on an old suzuki quad racer. Turns out the previous owner tried to put in a new crank seal ( the one on the flywheel side ). He didnt seat it all the way so air was sucking in there. It would rev high at idle, then bog out like it was running out of gas when I rode it.

That only applies with two strokes.