So I've been chasing this for a while. Backfires out the left side, won't rev past 5500 RPM.
What I've determined it's NOT:
Stator (traded with another one)
Carb adjustment (swapped carbs)
TORS (removed)
Parking brake sensor (removed)
Ignition is OK (traded CDI boxes
Weird stuff it's doing:
Bubbles in the coolant
Pops out the left carb and exhaust
135 PSI on the left, 175 PSI compression on the right.
Flywheel almost looks like it's vibrating fore/aft when the engine is revved up but this may be an optical illusion because of the engine vibration due to poor running.
The left exhaust pipe ACTUALLY TWISTS when the engine is revved, despite the fact that the pipe is secured and all the mounts are good. The right side is solid.
So, I need a plan of action. Where else to check? The condition developed over time.
Thanks for the assistance!