cg coil

[ts50x0]

my cg jerks and misfires when i go full throttle at low revs it gets ok when it gets to about 7,000rpm.
ive done the carb, valves and points. no better.
my mechanic said it coulkd be a coil breaking up. could this be true and if so why would it get better at higher revs?
is ther anything else it could be,
and by the way not the spark plug!

[gsxrboy]

It sounds like a fueling problem as the possibility of it being a broken coil would be constant and not controled by engine strain due to hard throttle at low revs.

Although the chance of electrical problem is unlikely I recommend you unscrew the spark plug cap from the ht lead and using wire snips cut off about 10mm of lead, keep it square as you can then re fit the spark plug cap (whilst the cap is off check the plug is a tight fit, this might mean removing the water shield, sometimes the clamp in the base of the cap becomes slack) If you can, do the same at the coil end, some are sealed some are not. Check the plug gap is correct and if you can afford it change for a new one as they are cheap. Also bend the ht lead and see if it cracks, if so replace it with a silicone replacement.

How many miles has the carb done? has it been in constant use or stood? You will need to reclean the carb and soak it in a solvent (removing anything that will damage) and get an air line on it.
Full throttle is controlled by the needle and main jet with the help of the emulsion tube. Make sure the emulsion tube cross holes are clear and the jet / needle are in good condition. Set the needle height half way. Try with and without the air filter.

Is compression good?

have fun