I`m restoring my Piaggio X7 2008 125cc E3 UK scooter, and decided to fit Malossi 218 cc cylinder kit (with stock head). I believe this is the same engine like on Vespa GTS 125 4v E3 2007-2015.
I Installed Malossi 218 cylinder with malossi recommended gasket. Bolted everything back together and now when I'm hitting start button, starter motor hardly can spin engine. If I remove spark plug, starter can spin engine freely as it supposed to. No hitting sound (if piston would hit the valves).
When i manually trying to crank engine with spark plug in (using socket and ratchet), at TDC on second turn it`s very difficult to turn over.
With charged battery engine can spin max 5-7 revolutions with 1-1,5 sec. delay in between. After that, I need to recharge the battery or wait some time so the battery can restore itself. Battery charged is providing 12.9 volts, starter motor is new. I checked all the wires/ connections, ground wire, everything is ok.
I have two questions:
1)Piaggio x7 125cc head dont have decompression system ( do I need to get one from bigger models like 200cc vespa/Piaggio, if thats what causing starter to struggle?) Is there any 125cc Vespa GT or GTS out there with malossi 218 cylinder and without decompression system that starts easely?
2) Is it a squish issue? Original 125 base gasket was 0.6 and cylinder heads metal gasket was 0.3
If somebody more experienced could help me figure out what causing starting issue?