Piaggio Leader E3 LC 4V 125cc + Malossi 218cc kit
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Piaggio x7 125
Joined: 07 Dec 2017
Posts: 2
Location: UK
Mon Dec 11, 2017 8:48 am quote
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?


LXV 150 3v ie. Midnight Blue (Sold)
Joined: 06 Dec 2010
Posts: 3009
Location: Bangkok
Mon Dec 11, 2017 5:27 pm quote
Don't know anything about the specifics of the kit but if you put a 125 head which had a 12:1 compression and now you have 218cc, your compression ratio is now :

218/10.16= 21.45

To get back down to 12:6 "theoretically" you need a 3.8 or 4mm spacer?

Did the kit come with instructions to machine the piston? Maybe that is taken care of by Malossi when they make the kit. Plus of course the combustion chambers on all models might be in the piston and as such the head chamber volumes is the same?

If the kit came with a new cylinder head I am talking out of my ***

As I said i don't know just asking.

As you say it may simply be you don't have the decompression bits on the cam chain wheel.
Granturismo 218
Joined: 04 Feb 2013
Posts: 5643
Location: South Carolina
Mon Dec 11, 2017 10:10 pm quote
After you try to start it a couple of times, what's the battery voltage, and what does it drop to when you try to start the bike?
Piaggio x7 125
Joined: 07 Dec 2017
Posts: 2
Location: UK
Tue Dec 12, 2017 4:09 am quote
waspmike - Malossi kit arrived with two base gaskets and one head gasket. According Malossi`s, if you use stock head, you need to use 0.8 gasket. And if you use Malossi 218 cylinder + Malossi head, than you have to use other 0.4 gasket. Head gasket the same for both applications.

If I remember correctly, Malossi using thicker base gasket to low down compression and prevent piston and valve possible contact.

Motovista - Battery is completely new (Yuasa Ytx12-Bs). I'm trying not to go too hard on it, and not to discharge too much (don't want to damage it).
After 4 turns (between every second turn, there is a delay <1 sec.) voltage drops down to 10 V, than starter starts to spin freely without engaging with engine.

I'm 99% sure it's not electric related issue. I've tried two batteries, and jumpstart. No changes. Feels like electric starter don't have enough power to crank engine over without delays.

Thats why my question is: Is there any Vespa gt/gts, gillera runner, Aprilia Atlantic, Piaggio x7/x8/e.t.c 125 Leader LC 4V engine with Malossi 218 cylinder and without decompression bits on the cam chain wheel, and is it starting easely?

Malossi kit: 3113955 for Piaggio Leader (carburetor)

LXV 150 3v ie. Midnight Blue (Sold)
Joined: 06 Dec 2010
Posts: 3009
Location: Bangkok
Tue Dec 12, 2017 6:40 am quote
My head is starting to hurt! Maybe someone else can get out their calculator? If getting a bit screwed up here.add to this that US models may have different compression ratios.

If you add the 0.8mm gasket you add 3.58cc to the combustion chamber volume.
I was working with 12.3 and 12.6 comprssion ratios which I found on line which maybe too high . Target according to Malossi info is 12.5
SIP Modern Vespa Catalogue Update 2015 by SIP Scootershop ...
MALOSSI has taken the motor tuning credo that 'Nothing beats capacity, except more capacity' and are now producing a 218cc Cylinder. ... aluminum / 75.5mm bore / 4- stroke / LC aluminum cylinder with a nicasil lined bore, increased cubic capacity, 1:12.5 compression ratio, 48.6mm stroke, fully compatible with the ...
Lets assume the 125 has also a 12.5 compression ratio. So we have to lose 7.44 cc to get 12.5 with a 125 head.

As I said my head hurts but I reckon you need a 1.66mm spacer to add the 7.44 cc's you need.

With a 0.8mm gasket you are running 16:1 compression.

I'll get my hat and an IBprofen
vespa gt 125
Joined: 04 Aug 2019
Posts: 1
Location: Essex UK
Mon Aug 12, 2019 7:53 am quote
same problem hard to start my vespa gt 125 with 218 kit on they dont tell you that so im either going to get decompression kit 35 pounds from racing planet or get a lithium ion battery which is 90 pounds
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