more problems with the cg125....

Having some real issues with my 125 at the moment.

When it's running, the I have to keep the throttle fully open to get any power from the engine, and the power I do get is really jerky. I have to keep the throttle on at around 30% for it to tick-over (I've played around with the idle speed screw, but it doesn't seem to have any effect).

I checked the air filter, which seemed to have a bit of damp in it so I dried it out and used some filter oil. Took the spark-plug out and the end had a load of black powder, which I believe means its running a bit rich. I took it out for a run after I'd done this, and its got back a bit more power (I can get up to around 30!) and it will just about tick-over.

When it's ticking-over, sometimes it'll almost cut out if I twist the throttle, other times it'll only increase the revs slightly, then really over-rev after I've let go:

https://www.youtube.com/watch?v=TE0x5sFrbLM

https://www.youtube.com/watch?v=NGTTf6Vdt7I

Any ideas of where to start solving the problem?

Cheers,

Tom.

first of all, what kind of carb are you working with? just a simple slide carb? did you check the needle height? sounds like it's getting way too much gas and it's choking itself to death when you twist the throttle.

Did you do any jetting when you changed your stock air filter to a podfilter?

my advise would be, take off your carb and set it to stock settings (float height, needle height, mixture screw) and work your way up from there.

Cheers, the carb was re-jetted set up by the previous owner and it worked fine over the summer.

I don't know a massive amount about carbs to be honest, it's the one that came from the original bike.

I've got the Haynes manual here so i'll have a go at resetting everything.

Tom.

So, took the carb off and gave it a once over. All looked fairly clean really, but I gave me a chance to have a proper look at the manifold and there's definitely a split in it.

I've just ordered a new one so hopefully that'll sort some of the issues.