Modern Vespa

Has anyone fitted 07 engine to 03 model 125..looking at the pictures seems water pump has 3 outlets rather than 2..is this a problem..could I use a t or y piece to run from cylinder head..

is the motor air cooled or water cooled? injected or carbureted?

the likelihood of the compatibility for a swap is very low. an 03 would be a leader series motor and the 07 would likely be a quasar series motor.

while the later motor will physically fit, the wiring would be a nightmare.

No they are both leader engines just the water plumbing is different..but thanks for input

sounds like you've got it well in hand then.

Is the water pump the same?

Don't know if there the same as I bought the ped with the engine already fitted..from what I can gather carb model heads haven't got as many outlets as 06 onwards..I imagine it's to do with emissions..
It seems I have 07 head on original engine going by the codes.. I have blanked the hose with bolt and sealant.. now to see lol

This is the extra outlet on the 07 head that needed blanking off

Also this part needs a grommet ..the thermostat housing is different

what's the other head look like and what do the pumps look like?

I don't have the original head..this is how the bike came...

I'm pretty sure the third outlet is a bypass so coolant can circulate in a loop before the thermostat opens. It wasn't on the US GT200 but appeared on the GTS 250.

The bike was running when purchased but appeared low on water..signs of water leaks..the hose in question had a bung.. but seems to be leaking..
Looking at the explos the later heads have a bleed valve in the thermostat cover and would cover the 3rd hole..
I have a grommet for 3rd hole and thinking of putting a hollow bolt with a bleed nipple into the outlet to help bleed off the air in system once refilled..
Hopefully this will work 🙏