Modern Vespa

Havent even received the thing in the mail yet, so I don't know what's coming. Any advice on the project? Can I do it with the engine in?

Hey SX.. yes you can do it with the motor in the bike.. you'll need to undo the rear shock mount at the motor so you can tilt the motor down in the back (cylinder pointing more upwards) to get the fins of the cylinder to clear the frame. (I take the rear hub/tire off and I use my harbor freight lift to lift the rear of the bike. You'll need to disconnect any wires, fuel line and cables that are going to get tugged on...

Then you can pull your old cylinder and piston off, take the circlips out of the piston, push the pin out, pull the piston off, put the new one on, and install your new kit (oil the piston and inside of the cylinder).. base gasket, piston etc. Then lift the rear of the motor up, slip the bolt into the rear shock mount and put everything back that you undid.

OR.. if you don't like working like that, you can pull the motor out and do it on a bench.. and be comfortable!

Once you torque the head down, run the bike up to good temperature, a good heat cycle and then re-torque the head nuts.

I hope that makes some sense.
Cheers

Another option is to remove exhaust from cylinder, remove cylinder shroud, remove head, remove all cylinder studs, put the piston at the top of the stroke, lift up the cylinder about a 1/4 inch, and then turn cylinder clockwise until the fins clear the frame and then gently turn the flywheel til the piston is at bottom of stroke. Remove cylinder.

No need to lower engine, disconnect shock, remove carburetor and air box, etc.

I would use the sfvsr method. have done it in the past. lazy man's method

I don't think it's the lazy method at all... I just have a tendency to take the long road.

Sweet, thanks both for your input. If anyone has anything else I should do, not do or otherwise watch out for I'd appreciate the heads up.

I'll add to my long approach! no seriously, just take out the studs.. and you might want to take a small file and chamfer the ports (windows) in the cylinder to make sure there're no sharp edges for the piston rings to catch on.. always a good idea.. this one is simple too (I promise)

In the past when I have gotten a vespa project, one of the first things I do is remove the engine entirely, which makes the second part of this even better.

When I remount the motor I put the king pin in port to starboard instead of the starboard to port.

That way when I want to remove the topend, I just remove the nut on the pin and back the pin out about a 1/4" and wala........

the motor will tilt out about an inch which is all you need.

Just a different method.

I see what you did there. Genius!

In fact you could just DO this BEFORE you do your top end! Just use a long enough piece of steel rod to keep motor located, then slip out thru the hole while you swap that long motor mount bolt end for end.