Re: exhaust mod
Ive ran a 1/4 tank through the motor and so far no movement in the fitting or odd rattles. I haven't even added a strap yet, which is a big no no. I'm going to pick up a tube of high temp silicon and try that on the fitting to reduce leaks. Ill keep everyone posted.
"They do make 1/2 to 3/4" couplings but if I were going to go with 3/4" I'd start at the cylinder and carry it through to the muffler at the rear."
To do what you suggest would involve some work on the exhaust port and use of a different muffler. If you have the "skillz" and wouldn't mind possibly ruining yr motor it would be a project worth doing.