Did you use starting fluid to start the engine again ? I don’t like using that stuff. When it explodes in a combustion chamber it can cause damage like braking piston rings or even cracks a cylinder head.
Not this time, but took a minute to start with the new carb on there.
Maybe yoy can just remove the cooling fin cover and try to to turn the cooling fin pulley by hand - if you can’nt turn the pully you have definite problems.
Another possibility is that the valve clearances have not been set correctly. A gas leak at the exhaust valve can cause an engine backfire if some unburned gas ended up in the exhaust.
I think the gas flow from the air filter box is probably an indication of incorrect valve clearance settings as well - the inlet valve probably opens at the wrong time and gas could be forced backwards into the intake system.
Thank you for the suggestions!
I will see if I have some time to dive back in this weekend, hopefully!
