Modern Vespa

Hello all,

Back again with questions on my first build.

So.... I've taken my head and cylinder off and I noticed something.

1) Piston doesn't reach the end of the cylinder at TDC, there is still about a mm to go. Is this normal?

2) At BDC Piston does not fully open the exhaust port. So there is still about 1 to 2 mm left before the piston starts to come back up. Is this normal?

Its almost as if the cylinder is sitting a little high, but there were no spacers used.

I'm starting to think that the cylinder is not correct for this P125X. There are a couple of markings on it, but I have not yet worked out what they mean. Any ideas?

Many thanks
Chief

This is normal. Piston to head clearance "squish" is generally very high on stock motors. Like 2-2.5mm.

Exhaust port doesnt really need to be fully uncovered at BTDC, as most of the gasses escape during the top 20% of the port being uncovered.

Thanks for the response, I appreciate.