well, believe it or don't, after 600 miles i still have the original exhaust gasket (the trick is tight/tight/tight) & i've replaced my intake gasket with black fiber material (thin stuff) gooped up with permatex 1A, it's held up for over 200 miles now.
I have been changing exhaust a bit trying to get a temporary one to work while waiting for my new pipe from Roland at spookytooth... but the bad welding job with an even worse welder broke while on the road and when I went to remove what was left 1/2 stuck to engine and 1/2 to flange. So, I figure might as well get a sheet for same price as single gasket and I should be set for a long time
Some of these chinese motors have poor welding and heat distortion of the mounting flange on both the intake and exhaust. I ground mine down untill both were flat. I made my exhaust gasket from scraps of high temp exhuast gasket made by mr gasket. I also replaced the studs with high grade automotive studs. Finally, I used two stainless steel nuts per stud to attach the exhaust pipe. The stainless nuts don't rust like the steel ones do. They are easier to remove if you need to. Brass nuts would also work well.
I had lots of trouble with these gaskets also. Two strokes get very very hot. Hotter than 4 strokes. My solution was to cut and drill a gasket out of a small sheet of soft aluminum.
Since starting my new motor it would not idle and was bogging down down up to about half throtle.
I remebered reading this from augidog and flatend my manifolds.
This fixed it
The intake gasket looked like it was ok but when I put a straight edge across the screw holes on the flange I could see plenty of sunshine where the hole is
I then realised that the motor was getting far more air than it should have via the flange.
Today I rode it and adjusted the mixture then it ran like a dream.
Pulled well from idle (yes now it does!) through to top end.
I did replace the gasket with a new home made one.