spitfirecycles

New to this forum.... and need some help please?!! Bought a Ty175 a few months ago that has stood for 15 years un-used. Rebuilt the carb, fresh fuel and new plug and she fired up first kick!! Well chuffed! Had a problem with dirt in the fuel, so have Pet-Sealed the tank and now have very clean fuel. Bike still starts great, but when I select first gear and pull away, she starts to die?? If I slip the clutch and keep the revs up, she will keep going and she will eventually burst into life?!! That's OK, but have tried her off road, and it is very hard to control like this?? Any ideas???? It is almost as if the carb is over fuelling, but have checked jets, needle setting etc. and all seems good? Any help would be greatly appreciated!! Cheers!