Modern Vespa

I was on a ride out and my back wheel locked up on my Vespa.. It seemed to be using too much fuel. I left it for about 20 minutes and it started again but I got 15 miles down the road and it broke down again. It has no compression on the kick start. Can anyone give me an idea of what might be the problem. I'm running a 177 pinasco kit on it... ?

This is the perfect description of a "hard seise". It is caused from too much heat, typically from running too lean (not enough fuel mixed with the air). The lack of compression is due to the face of the piston being seared like butter over rings and trapping them in place. This prevents the rings from sealing, resulting in no compression.

You are looking at a new cylinder/piston at least, followed by proper jetting.

How long have you had the kit on? Any other problems? Engine racing at idle, not shutting off when you hit the kill button? What carb are you running and what are the settings (how many turns out on mix screw)? What jetting are you running? You seized if for sure. Take the top end of and inspect. You may be able to get away with a bore and replacement of piston and rings.

Fixing the top end is the easy part, you need to figure out what caused the seize in the first place. Too lean a mix is definitely a cause. If you have a blown seal that could cause too much air as well.

Sucks. Could have holed that piston. Pull it apart and post some pictures.

Don't know where the OP is and hopefully its been sorted but saw this on the interwebs...