Modern Vespa

Thanks everybody,

I gave up on the big bore motor because starter couldn't get past compression stroke.

Got a new used motor.... With its own problems.
I've got a nice healthy spark with new Stater and CDI

90 psi compression while cranking on the starter without any oil assist in the cylinder.

Everything I've seen says that is pretty much enough to get things started ? Also I've read that could be higher up around 130

I have sprayed ether into the intake, spritzed gasoline into the intake... It's almost like the spark is happening at the wrong time?

The motor shows no signs of being rebuilt
Anyone ever seen anything like this

Throttle wide open? Throttle closed will give a low reading.

If still low, try a couple squirts of oil. These have iron bore, if improperly stored could have bore corrosion. If number goes up bad ring seal confirmed.

90 is very low for a four stroke to run. I think that might be your issue.

Okay thank you everybody.... I'll give a couple squirts of oil in the cylinder and get back let you know what I find.

I'm just amazed that even with low compression ether- starting fluid would not ignite really?