250B Linhai Carb hard to adjust By robert1c (Read 933 times)

[robert1c]

have a Linhai 250B and i have been dealing with an issue of trying to adjust the carb.
i let it warm up and then try to set the idle to the point right before the rear tire starts to turn. if i leave it there it may be right about 1800rpm which is good but the issue is during a ride if i stop at a light sometimes it drops to about 1100rpm and tries to die. if i feather the throttle to 1500rpm it idles fine there but if i let it go it drops. the other issue is to get it there it idles at around 2200/2300rpm at cold start.

i have added a K&N air Filter and a straight though performance exhausts. the fuel mixture is at 2.5 turns out.

Any help at what i should be looking at would be appreciated.

Thanks!


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[alleyoop]

It is running LEAN, Adjust the FUEL RATIO MIXTURE it probably needs more fuel to keep the idle.
2 1/2 turns is only a good starting point but since you put on a K&N Filter which allows more air in and a Performance Muffler you need more fuel. So turn the Fuel Ratio Screw Counter Clockwise AFTER IT IS WARM and adjust it to get the HIGHEST IDLE from the FUEL RATIO SCREW then if it is idleing to high LOWER THE IDLE USING the IDLE SPEED SCREW.
Allwyoop

Here is how to adjust the FUEL RATIO MIXTURE:

First Start up the Scoot and let it warm up At Least 5 minutes so the ENRICHER cuts off the Extra Fuel.

YOU WANT TO GET THE HIGHEST IDLE OUT OF THE FUEL RATIO MIXTURE:


So from where it is currently set FIRST TRY richening it up more:

1. Turn it 1/4 turn Counter Clockwise and wait about 10 seconds to allow the motor to catch up with the new setting. LISTEN or look at your tach:
a. If the IDLE GOES UP REPEAT #1, UNTIL the IDLE does not change or drops a little THEN TURN THE SCREW CLOCKWISE 1/8 and that should be the highest IDLE from the Fuel Ratio Mixture and go to #3.

**** IF ON THE FIRST 1/4 TURN COUNTER CLOCKWISE THE IDLE GOES DOWN OR DOES NOTHING, TURN IT CLOCKWISE 1/4 TURN TO GET IT BACK TO WHERE IT WAS AND GO TO #2****

2. Turn it 1/4 turn Clockwise and wait about 10 seconds to allow the motor to catch up with the new setting. LISTEN or look at your tach:
a. If the IDLE GOES UP REPEAT #2, UNTIL the IDLE does not change or drops a little THEN TURN THE SCREW COUNTER CLOCKWISE 1/8 and that should be the highest IDLE from the Fuel Ratio Mixture and go to #3.

3. If the idle is TO HIGH NOW LOWER the IDLE USING the IDLE SPEED SCREW so that your REAR WHEEL JUST WANTS TO TURN... Go to #4.

4. Now give the Throttle a quick twist and let go, the Motor should Rev up nice with no sputtering or hesitation and come back down to where you set the idle.

*** IF TURNING THE FUEL RATIO SCREW Clockwise or Counter Clockwise DOES NOTHING Then the Pilot Jet AND OR ITS PASSAGE ARE Clogged and you will have to clean the Jet and CLEAR OUT THE PASSAGE. And go through the Procedure again***