Hello all ,
Yes It's a oldie but I got cheap.1986
It was sitting for a while,the guy before me cleaned tank and has fresh gas.
So heres the jist. It only runs on choke.
Carb was rebuilt (not by me) lotsa new brass main jet,Pilot jet,air screw.choke brass and all new o-rings. jets look like stock numbers
What are screw setting? needle clip?
I have not looked into the valves
would valve do this?
I need settings intake/exhaust?
Does anyone have a good used carb?
thanks in advance for any help

 

If you have the YFM 200 Moto4 with the built-in front rack between the front fenders, and the carb # is Mikuni VM22SH ID # 52H-00, then the stock main jet is a 115, the needle jet position is # 3, and the pilot screw turns out 1.5 turns. If your carb # is Mikuni VM22SH ID # 1NU00, then the stock main jet is 117.5, the needle jet setting is the same, and the pilot screw is 2 turns out. Valves would not make it do this. Sounds like you're not getting enough fuel. But for the record, valve clearances are: Intake - 0.05-0.09mm Exhaust - 0.11-0.15mm

 

Thanks for the info
One thing I did find that was odd is that there was two o-ring where the piolt valve goes. Is there something missing here? what is the stack up EX>. Screw ,spring washer o-ring ? Is there suppose tobe two orings?
Thanks againg

 

hey, I have a 1986 yamaha moto 4 200 with the exact same problem, does yours run on choke, but still sputter a lot and not run well?

 

Mine had the same problem. I cleaned out the carb pretty good, but it still didn't run right. I cleaned it out a second time, but this time I made sure all the tiny holes in the pilot jet were clear (I missed some the first time), and now it runs much better, don't need the choke, it actually idles.

 

I have the same exact problem. I have an 86 YFM 225 (Moto-4) and I have soaked and cleaned the carb in gas 3 times. I t get progressivly better but still not enough to run right. At first it would run without the choke. then I got it to idle without, but no matter choke on or off when I give it som throttle is boggs down and dies out. Any suggestions?????

 

It needs a good soaking in lacquer thinner. My Terrapro 350u had been sitting for a couple of yrs and was varnished really bad. I took apart a far as I could get it and place it in a bucket paint can sized and poured the thinner in and let ti soak for three hrs and then blew it out real good with air hose. Put it all back together and hit the starter and fired right up with out a sputter!! Try it It works. Just make sure that there are not any O rings in there. Hope this works for ya.

 

i noticed in the shop manual for my moto 4 200 i have the carb diagram shows what appears to be a spring and something else going in with the pilot screw which there isnt in my carb and my pilot screw backs itself out is there something that is supposed to be in there or no please help it still wont run i got it to idle without the choke but as soon as you put in gear itll die and if you sqeeze off the rubber boot on the mouth of the carb it will run better and drive.

 

 

Mine runs but Idles so dang high it just takes off from my son its crazy! I'm just going to buy a new carb cause cleaning and rebuilding ain't doing the trick