Yup. G1 was made from 79 to 89. I think mines a 82 or 83.
It felt like it was under powered. Put a new cylinder and piston in last year. Still was weak. Gonna see how well this works.
The 2 stroke karts used to plug mufflers all the time. Loosen the bolts or springs holding it on and take it for a ride. If it ran better replace the muffler. If it stayed the same replace the piston and jug.