My gasser txt280 limited edition 03yr, Has a annoying way with spark plugs....after 4 to 8 hrs use, when i come to kick it up it starts ok but then starts running lumpy then fizzels out and stops. I then check spark plug,the end is black and sooted,replace plug and everything hunky dory for the next 8hrs.

My petrol mix is 65cc of synthetic oil to 5 litres of petrol, is this the norm with my model......?

cheers Dave

Hi Davet,

check list - air filter clean, carb clean, mixture screw set correctly?

Confirm the above and see how you get on.......basically sounds like its running a bit on the rich side? Fuel to air ratio rather than fuel/oil ratio.

GJ

Hi GJ

Yes clean air filter, take it out every 3rd outing and clean.Carb clean..mixture screw size 38 was told to screw all the way back then unscrew 3.5 turns.

If it is running rich which way should i screw in or out ?

cheers Dave

Hi GJ

Yes clean air filter, take it out every 3rd outing and clean.Carb clean..mixture screw size 38 was told to screw all the way back then unscrew 3.5 turns.

If it is running rich which way should i screw in or out ?

cheers Dave

Dave,

The 3.5 out reccomendation should be a starting point. To correctly set the mixture screw (turning in will lean out the mix) warm the engine and quickly blip the throttle open/close and adjust the screw in/out to get the best response.

Each bike and ambient conditions are slightly different. If 3.5 would work with every bike under all conditions, they would set it at the factory and be done with it and this is why the adjustable screw is there. The mixture screw fine-tunes the pilot circuit, which "pilots" the air/fuel ratio from idle circuit to when the needle jet starts to draw fuel. Without it, the engine would tend to die every time the throttle was opened quickly.

Jon

This happened to me once and it was the float not adjusted right. If the carb is full and gas is still coming in its flooding the bike, just remove the bowl from the carb and with gas still hooked up push the floats up and if the fuel don't stop thats your problem.