The new topend has 125# of compression. By fire yes I mean spark, and I will have to check that out about the timing. So the nub at 3'oclock is on the flywheel itself and should be at 0 degrees?
Also I have not cleaned the carb since rebuild. It was apparently running before it toasted the piston so I assumed it should still be fine. i will get some carb cleaner as well.
Check out the carb and your reed petals. Not wanting to start could be caused by either a gummed up carb that's sat for awhile, or faulty, chipped, or a broken reed petal. Look in on the reeds when you pull the carb to clean it. Clean it with carb cleaner, and blow out all the passage ways with some compressed air after. I like to take out the main, pilot, choke, and air screw and look at them in some good light to make sure their clean and open.
Also I have not cleaned the carb since rebuild. It was apparently running before it toasted the piston so I assumed it should still be fine. i will get some carb cleaner as well.