Modern Vespa

Hi finally got all my bits to start rebuilding the engine but dropped thermostat screw into head..dope...so obvious got to take head off..so head off now stumbled up against this

This piece

That's just the SAS system. Somebody's pinched the tube shut when they eliminated it from the motor.

Hi thanks for the reply..its obviously been leaking with all the rust around it..
Can I get a blanking piece for it if not used..or replace and block better..

I don't believe there's a widely available block off plate available. when I eliminate the SAS on GT/LX models I just fabricate a little plate to block it off.

be sure to reuse (or use a new) gasket with a little schmear of some appropriate gasket sealer.

also, if that's leaking water, then you have bigger problems.

I can make a plate if none available to buy..
I assume it was a water pipe by the amount of rust around it..
What problems do you see ??
It's an 07 head on 03 barrel..
Wish I'd kept my t5 now

no, it's not a water pipe.

you should probably review the workshop manual

I'd love to help, but honestly I don't know what you're working with here. it's a real bitsa situation and you seem intent on making it all come together, so I don't feel like I can offer much in the way of assistance.

the 2003 didn't have the SAS system. The 2007 and later did.

Take that thing off and stick the head on a piece of glass or a mirror. Does it wobble? If so, take it to a machine shop to be decked. Otherwise, get a couple sheets of 1000 grit sandpaper and run the head back and forth on the sandpaper until it is smooth clean aluminum. I would leave the plug in and hit the combustion chamber with a soft wire wheel on a drill. Leave the head face up, and fill the combustion chamber with gas. If the gas is gone when you get back in a couple of hours, lap the valves.
As far as I remember, you can switch to the thermostat cover off the GTS, which this head is set up for, but you will need to cut the top water pipe or replace it with one for the GTS. The Thermostat cover on the GTS is less complicated, and a lot less fragile. Most of the GT thermostat covers we sell are to replace one where one of the little inlets on the side have broken off.
The old head gasket for the GT was a thick, fibrous thing with a pattern that matches the print on the head you have. The new one for the GTS125 will work, and you can get them in various thicknesses. Go with .04 or .06mm. You will have a slight increase in compression and performance.
I have a bunch of 125cc liquid cooled gaskets in some gasket kits that I boutght, and I can't use them because the Leader 125 LC was never sold in the US. If you were closer, I'd give you a lifetime supply. If you do decide you need one or several, let me know, and I'll figure something out.

Excellent reply motovista really appreciate.
Will try your advice today..

Hi I have bought a engine just for the correct cylinder head and spare parts..I can only find a head gasket in 0.3 or 1 point something..
Is the 0.3 OK to fit to 125cc