RT125 driving me mad-carb problem

[djsbriscoe]

Hi,
I've been trying to solve a carb petrol overflow problem on my RT125.
First a little history.
1/ Carb float bowl has been overfilling and leaking petrol out of the overflow pipe.
2/ This has been upsetting the idle speed of the engine, It idles ok when starting up, but the carb then overfills when the bike is moving.
3/ I have tried to set the carb float level at least 5 times using a digital vernier caliper to the height quoted in the service manual. The carb still overflows.
4/ I have fitted a new needle valve and seat (as a set), a new float.
In desperation I sent the carb to someone to check over for me. He said the float level is obviously too high, even though it was set as described in the manual.
I have just got the carb back, and fitted it to the bike. I did not check his work,assuming he new what he was doing. The float bowl no longer overfills but the engine will not idle at all. If I use the choke to start the bike it starts ok but runs too fast. Also the engine overspeeds when I close the choke and occasionally backfires into the exhaust (excess petrol igniting in a hot exhaust).
The bike ran better before (at least it did idle, even though erratically) but the petrol overfilling was annoying.
I would be tearing my hair out if I still had any. This bike is driving me mad.
Can anyone help me to shed light on what more I can do to sort out this problem once and for all (apart from selling the bike-I am that fed up with it).
Can anyone offer me any help to adjust this carburettor?
Hope someone can help.
Thanks,

David.
London, UK

[DAVID THOMPSON]

sounds like engine vacuum is drawing in more than needed
also
drop your float by its self in a bowl of gas and see if it sinks or floats
dave