Modern Vespa

Hello, engine in my 2014 Vespa GTS 125 (M455M) lost oil during the ride and now it is seized/rubbish only I can buy reasonably priced 300 ie engine (M454M) from 2014 GTS. It is complete (incl. throttle/ECU, immobiliser), but no ignition switch and key. Question is: is it easy doable to swap this engine to my bike? Can this be done without ignition switch? Thanks in advance, J

without the key you'll need to get the immobiliser inside the ecu reset so it can be paired with different keys (could probably use you existing keys one the ecu is reset). the ignition switch and antenna are not the issue.

the wiring harness may have different connectors in particular the one to the ecu. even if this plug is the same it may need repining due to different assignments. have a stare at the wiring diagrams on https://manuals.wotmeworry.org.uk/Vespa/ and spend some time skimming through the service manuals

need to check things like where the coolant hoses will route. if your 125 uses an electric water pump you'll have to remove it as the 300s all have the water pump as part of the engine.

no idea about the rest.

not so sure it will be "easy" but of course anything can be done with enough effort