150psi and spark...check

250cc 2-smoke should start with this correct?

150psi came on 3rd (40, 100, 150 approx when kicking)

Unless it's flooded out/fouled plug, I would think.

only missing fuel and proper timing of spark

So true. I had an 80's Husky once that was hell to start, and it turned out it was a total piece of cra- uh, I mean, the ignition timing was way, way off.

I've bought a ton of 2 stroke that guys said "it ran great the last ride i was flying then it would not restart the next day" sheared the flywheel key when they hamered a big jump or log etc. $2.00 fix.

44

well this is a 78 IT250. here's to hoping that it's just a mildly dirty carb

If it has reed valves check for a bad one. It will still have compression with a bad reed, but you won't get a good air/fuel charge to the combustion chamber. IDK if a '78 yamie IT is reed or piston port induction, but reeds were showing up on a lot of Jap MX bikes by that time.

Bugger off canoe!