New trike wont run for beans...

[Mi-lptroll]

So I just picked up a 1983 (I think) YTM 200k. It didn't want to stay running so I pulled off the carb and cleaned it. Slapped it back on and I can get it to start up but still wants to shut off. Only way to keep it running is to keep feathering the throttle. It is also idling high like its running rich. Backfires a little when feathering the throttle so I think the valves need to be adjusted, something I don't know how to do. Still doesn't like to stay running.

Heres what Ive done so far: Cleaned the carb, replaced the spring on the choke because it was sticking open, replaced the hose for the carb joint because the old one rotted in half. It is getting good spark.

So I'm not very experienced with small engines or carbs. If I know what to do I can do it, but that's about it.

There is a clear/brown hose (vent hose I believe) coming from the top (not the bowl drain port on the bottom). It seems to be sucking air? if I pinch it off the engine shuts off immediately. I have tried adjusting the air screw and just cant keep it going. Any ideas? I think I need to swap the bowl gasket because it is leaking a bit but that shouldn't affect the motor running or not right?

Thanks Guys for your time. Any and all ideas are appreciated!

[thcowboy]

I would just turn the jet a turn or two to the left. Also check the plug, if its black its rich and screw the jet out. If its white (i dont think so) its lean

[Jmoozy27]

Sounds like you need to rebuild the carb. When you cleaned it did you remove all of the jets and blow out all of the orfaces or did you just clean the bowl? Air screw should be turned all the way in and backed out 2 full turns.

[phantomtracer]

There should not be any hose attached to the carb that sucks air.
I would resolve that issue first.

[Mi-lptroll]

Are you talking the actual jet in the carb or the air screw on the outside?

[Mi-lptroll]

I pulled al of the jets out and sprayed all of the ports and every orifice I could out with carb cleaner. I then used torch tip cleaning "files" to get the gunk out of the main and pilot. Started with the air screw bottomed out and came back out 2 turns to no avail.

[Mi-lptroll]

That is what I figured and for some reason I think it is. I say this because when I pinch off the vent hose it kills the engine. The real question is why.

[sweetip2000]

There is an idle air control its the one that usually has a spring on it outside of carb and you can usually turn it with a screw driver. If it stalls when it idles your idle may be low so you have to turn it clockwise to the right to raise idle. I would find out the make and model of the carb and or find the service manual for that specific bike. If its the stock oem carb the service manual will tell you how to get the settings right on the carb. Ask around the forum and you will usually get great feedback.
I know how frustrating it can be but it will be worth it when your all set and riding it.

[Mi-lptroll]

I downloaded a service manual a little bit ago and kind of browsed through it a bit. will have to do some more reading tomorrow for sure. The engine stalls at idle but once it warms up via use of the throttle it idles high like its running lean? I don't want to have to take the carb off again for the 8th time in 24hrs but if that's what it takes that's what I will do. Tried adjusting the screw you mentioned and it seemed to help the idle a little bit but was still trying to quit on me or go high idle.

[Jmoozy27]

You may be turning the idle screw. It is usually even with the throttle valve. The air/fuel mixture screw will likely be between the throttle shaft and intake manifold. The manual will explain better.

[Mi-lptroll]

So I read through the part of the manual on the air screw and the idle adjustment and tried making some adjustments but either theread is another issue that is hiding my adjustments or something is stuck As I didn't notice any changes. When I cleaned the carb I didn't take either adjustment screw out so perhaps I should pull them and clean them? The springs could be shot as well, I had to replace the one on my clutch cable because it was sticking open.