Hanging RPM By wolfstar135 (Read 1,221 times)

[wolfstar135]

I have a 2011 Jonway YY250T 244cc with 150 miles on it. I changed the fuel lines and clamps. When the engine is at operating temps and riding to a stop the rpm is around 3000 rpm and then slowly goes down to 1800 rpm. This is wearing out the belt. What should be done next?

[alleyoop]

If the RPMS HANG and slowly drop it is LEAN, Turn the Fuel Ratio Mixture screw Counter Clockwise 1/4 at a time and try it after each 1/4 richer.
Alleyoop

[wolfstar135]

I will try that. Thanks!

[justbuggin2]

Alley is the carb guru one other thing to check is that your thottle cable is free and not binding

[alleyoop]

Good point Justbuggin2, to Verify that the THROTTLE CABLE is not binding Twist the throttle and let go it should snap back immediatley.
Alleyoop

[wolfstar135]

I can't seem to find an idle mixture screw on the carb. Am I correct that the the top diaphragm has to be removed and adjusted?

[alleyoop]

Here is picture of what your carb most likely looks like and notice where the FUEL RATIO MIXTURE is.
Alleyoop

LEFT SIDE OF CARB:


RIGHT SIDE OF CARB:

[larsliederhausen]

very nice helpful pics alleyoop.

[wolfstar135]

Thanks for the pics! Now I need to find some tricks to adjust it. Any suggestions would be very helpful.

[alleyoop]

If you have a small interchangeable head screwdriver set that works best or just the head will do and you can get your fingers under it.
Alleyoop

[richardthescooter3]

It isn't easy, but can be done

[justbuggin2]

take a long piece of a heavy coat hanger wire hammer the end flat and grind the end so it looks like a screw driver and bend a 90 on the other end then you can fish it though to the A/F screw

[wolfstar135]

Today I attempted to adjust this screw and decided to take off the air filter box so I can see what I am adjusting. I also removed the long left lower plastic under the floorboard too. Now I see a brass cap over the screw. Maybe someone can tell me that I can remove it without dismantling the carb to drill it. I hope it is just pressed on and can be removed easily with some force.

[wolfstar135]

I just read another thread about idle speed and it was mentioned that there is a cover over the fuel mixture ratio screw. I will try to remove it with some pliers and go from there.

[alleyoop]

Sorry I forgot to mention about the plastic cap over the screw. It is there to discourage making adjustments to the Fuel Ratio Mixture the EPA wants them to run LEAN(HAHA).
Alleyoop