Valve adjustment ? By tomkimack (Read 897 times)

[tomkimack]

Hey guys, please help me out. I bought a non running Roketa 150 cc scooter for my wife. After replacing throttle cable, battery, spark plug, and some wiring work I got it running. Problem is it will only idle at at about 3000 rpm or higher and dies alot. I figured it was a bad carb and replaced it with a brand new one. No change. I triple checked all vacuum connections and intake and gasket for cracks and found nothing. Before I tear into the engine could this be a case of valves needing adjustment? Thanks, Tom

[Alleyoop]

Yes, do a valve adjustment Top Intake .004" and Bottom Exhaust .005". It should idle around 1500-1800 rpms and the Rear Wheel SHOULD NOT be spinning. Have you adjusted the Carb here is how to adjust the Carb this Carb may be very simliar to yours.
Alleyoop
LEFT SIDE:


RIGHT SIDE:


ADJUSTING YOUR FUEL RATIO SCREW:

Warm Up the SCOOT for at least 5 minutes.

YOU WANT THE HIGHEST IDLE OUT OF THE FUEL RATIO SCREW YOU CAN GET.

ADJUST YOUR RUEL RATIO:

1.Turn the Fuel Ratio Screw Counter Clockwise 1/4 and wait 10-15 seconds to allow the engine to catch up with the new setting.
a. If the IDLE GOES up repeat 1 until the IDLE does not go up or it does nothing.
b. Then turn it 1/8 Clockwise that should be the highest IDLE you can get out of the Fuel Ratio Screw.

**** IF on the First 1/4 Turn the IDLE DOES NOT go up or does nothing THEN Turn the Screw Back 1/4 and GO TO 2.

2. Turn the Fuel Ratio Screw Clockwise 1/4 and wait 10-15 seconds to allow the engine to catch up with the new setting.
a. If the IDLE GOES up repeat 2 until the IDLE does not go up or it does nothing.
b. Then turn it 1/8 Counter Clockwise that should be the highest IDLE you can get out of the Fuel Ratio Screw.

*** IF 1 OR 2 DOES NOT CHANGE THE IDLE you have a Clogged Pilot Jet or its Passages and you will have to Clean the Jets and Passages out.***

If all is well then you can Lower Your IDLE if need be USING the IDLE SPEED SCREW. Idle should be around 1500-1800 and the REAR WHEEL should NOT be Spinning.

[tomkimack]

If I turn the fuel ratio in I get no change, then it dies. Out makes no change at all. Probably because the rpms are too high. Thanks for the help. I will be adjusting the valves tonite. Thanks, Tom

[Alleyoop]

You are correct, it would not make a change since the rpms are so high, get them down to about 2000 rpms and then it should make a change.
Alleyoop

[Kaveman]

idle adjustment screw in too much ?? That also would keep your idle rpms too high as your describing !!
Bill C.

[tomkimack]

Thanks, guys. I adjusted the valves and the scooter runs great !!!!!!!