Modern Vespa

I got interested in scootering about a year ago, here is my scooter project. A modern Vespa with a 2 stoke engine (had to be 2 stroke) and bigger than 50cc - the biggest 2 stroke engine I could get my hands on.
Along the way I made lots of assumptions and a trunk load of mistakes. It took me the best part of a month in my spare time.

There's not much eye candy in my project - I do like a nice shiny paint job on a scooter so I consulted my stylist and she advised me the "ghetto" look was in this season , so I took function over form.


To start with I bought a 2006 model Vespa LX50 2T from a guy who was going overseas. He had dropped it a few times causing some cosmetic damage and scratches. It had bald tyres, but the engine ran OK the frame looked straight enough.. We struck a deal - and I had a cheap scooter.



On the LX-50 I wanted to make sure the brakes, suspension and steering bearings where OK, adding more engine power requires greater stopping power and I wanted a solid platform to build upon. My thought was if the LX frame can take the power of a 150cc 4 stroke it should be up to the task of a 150cc 2 stroke. That makes sense, erm...right?



I started work on the LX50 scooter. I dismantled the steering fork and replaced inner and outer wheel stub axle bearings. I installed a new front shock and coil assembly. I refurbished the disk brake calliper. I replaced the upper and lower steering column bearings as a complete set. To fit the shells I used charging freezer spray and a 2kW hot air gun to shrink and expand the bits respectively. I reassembled parts onto the control fork and fitted it into the frame as a complete assembly. I replaced the hydraulic fluid, and bled the system of air. I was happy the front end was up to the task.[/img]


2006 model Vespa LX50 - 4 years in the hands of one careless owner. Now owned by someone with even less careful plans. I think the exhaust is an aftermarket Sito.

Front forks away.

front bit missing: Note hammer.

being pulled apart

Steering fork on the bench

old shock - new shock - spring design a bit different.

Next thing was to find a suitable engine. In Australia this proved to be very difficult. A lot of searching and zero luck, unless I wanted to pay a small fortune and get parts shipped from UK. At this point I almost gave up. Piaggio never imported the Typhoon (125), Hexagon or Skipper into Australia, or so it seemed. Therefore no local source of suitable second hand parts.




I eventually located a Skipper 150 2T in New Zealand - I had it stripped and shipped with all parts less the frame, so no import tax. The parts and shipping cost me more than the scooter. My wife and I just had our first baby - I worried my priorities as a new Dad might be in the wrong place. I promptly disappeared into the garage to begin work.


I degreased and cleaned the 150cc engine, a number of the air cowling screws had snapped off so I drilled these and tapped new threads. I examined inside the transmission cover - the drive belt, clutch and oil pump appeared OK. I took the starter motor out and tested it. I looked down the exhaust port. Turning the engine over by hand the compression felt very good. I put everything back together and hoped that it would work.[/img]


Piaggio Skipper 150 2T

Same engine - different angle

another view of the motor assembly

the engine from the underside

With the engine on the bench


Engine on the bench

from the top view. intake taped up.

transmission covers off

close up of the oil pump

Now I pulled the wiring loom out of the LX50 and replaced it with the loom from the Skipper 150 - I cut and sleeved onto the LX50 control switches and senders. Much to my amazement, the wiring colour codes between the two looms where almost identical, thanks Piaggio!


skipper 150 wiring harness

fitting the skipper 150 wiring harness

in the battery box

The Skipper uses a complete DC system - the LX50 uses both DC and AC. The Skipper 4 way fuse block fitted perfectly inside the LX glove box. I added a dual pole switch onto the top of the leg shields for riding lights on / off - All other handle bar switches functioned as per LX50.

The voltage regulator fitted into the spot behind the horn cover. The CDI ignition fitted onto the existing bracket, the HT coil fitted neatly into a spot at the base of the footboard. The starter relay went perfectly near the battery box. The indicator relay fitted inside the leg shields easily enough. Where I cut cables I used double wall heat shrink to sleeve wires. I used black self amalgamating tape to tidy up loose ends, to finish I fitted a 9Amp battery.


inside the LX glovebox went the skipper fuse block and I added a DC accesories plug - this pic I took after the scoot was finished.

handle bar control wires

the skipper 150 ignition components. This pic out of sequence

The LX uses an engine swing arm that is completely different to the Skipper engine mounting. This caused me the most concern because I did not know how best to proceed. I modified the LX swing arm by cutting 5mm from each end of the engine side shaft then cutting a 4mm arc to allow the exhaust down pipe to clear. I took a picture and illustrated the changes made.


the modified engine bracket with the change dimensions I made

Time came to unbolt the 50cc engine from the LX frame. Once clear I put the two engines side by side, to have a look. At this point I discovered the LX centre stand would not fit the skipper engine - so have to live with a side stand. The Skipper engine is longer which proved to be a problem later. I struggled to attach the Skipper engine - it would have been a lot easier with 2 people on the job.


50cc engine pulled out

LX frame with engine removed

The 50 and the 150

same engines, different angle

Oh dear, the 150 is quite a bit longer... hope that does not cause a problem later.

A view from the uinderside of the sipper 150 engine with LX engine sway bar bolted on. Note exhaust downpipe clearance.

thats close.. but it was enough to do the job and worked out very well in the end

Now with the 150 engine bolted in place the LX has a noticeably longer wheelbase. The standard exhaust and airbox foul up against the LX frame with the rear suspension under load. To overcome this I fitted a 5cm lifter at the case rear shock point. I cut a 10cm wide and 5cm deep arc from the LX tail guard to clear the air box and I cut 10cm from the length of the rear splash guard to stop it catching on the back of the number plate.


putting the 150 engine into the frame was hard work for a single person. Lesson learnt : work with gravity, not against it.

almost in.

secured all the chassis bolts and took a step back to see what I'd done. looking low at the back. I like it, but it needs more work

a lifter was needed.


Before the lifter

raise me up. IGA 5cm "hijacker"

much better clearance on the exhaust and frame.

The Skipper engine was fitted with a Mikuni VM-20 carburettor. I got my hands on a brand new Dell'orto PHVB 22 fitted with a 95 mainjet - by chance this turned out to be a near on perfect jet size, slightly too rich for the standard airbox and exhaust, good thing with an air cooled 2 stroke. I fitted a big PM Tuning reed block. The inlet manifold was sealed up with silicone, it looks ugly but is air tight enough. I mounted the EGT probe into the side of the pipe. My thought was, if I see the gas temperature going too high then the mixture would be lean which would serve as an advance warning of piston seizure.


VM-20 left PHVB 22 right

same again, this view from the airbox side. PHVB has a 95 main jet.

mount for EGT probe

the standard exhaust - which is a catalytic converter

exhaust fitted with EGT probe installed

I hooked up the fuel line, 2 stroke oil feeder lines - made sure they where purged of air. Fitted a new spark plug and was good to go.. I cranked the engine but the scooter failed to start - I checked there was a spark at the plug, yes very good. I discovered the auto choke plunger was a bit dodgy so installed a manual choke control. Now the scooter started - only just, there was an awful lot of blue smoke. I looked at the oil pump and noticed it was out of adjustment - very far out of adjustment. Should of checked that earlier eh? I set it right on the marker. Now the scooter started and settled to a nice idle when warmed up.


PHVB carb. attached to inlet manifold

The first test ride, slowly up the street carefully monitoring everything - did a few slow figure of 8 turns and brake tests, carried on with slow laps around the block for 10mins. Back home I checked all the major suspension mounting points - Spent some time going over everything looking for stuff that might have come loose, moved or fouling up in bad way. All seemed good and OK. I was keen to go for that second ride, but left it so I could start the scooter again from cold and in the mean time got to bed - I'd been working on it all night and the sun was just coming up.
Second ride, warm up the scooter and rode slowly around the neighbourhood for 10 mins or so, double check indicator and brake lights working. Now to my selected test track; a flat straight road running parallel to a golf course, almost no traffic, It's about 2klms long. Perfect. Slow take off leading to max throttle held until I ran out of road. A few more runs gaining the nerve to glance at the instruments; The EGT was displaying just over 800c - the tacho displayed approx 6000RPM and the speedo (being the LX50 instrument) was pointing somewhere near the LCD clock. It made me wonder if the standard Piaggio CDI has a rev limiter?
If I twist the throttle sharply from standstill the front wheel pops up which caused me a great deal of panic the first time it happened. I had a Conti Twist tyre fitted to the rear wheel and while I was there decide to spray the rim black.


chocks away

non standard instrumentation - perfect viewing position made from a broken stem mirror. Looks a bit silly but very useful during set up and adjustment

the join point on the exhaust system

The exhaust gasket failed at the connection between down pipe and muffler sending a jet of hot exhaust gas into the plastic air intake cowling and melting a hole through it. I replaced the gasket and made a heat shield in case it happened again - which it did.

I have been riding the scoot for a few months now, I depend on it for my daily transport. It has not let me down. It goes very quickly and the handling feels solid and balanced, both brakes work brilliantly. I told myself at the beginning of my project if the scooter felt unsafe in any way beyond my ability that I would can it.


exhaust leak blew a hole through the air cowling.

this is the join point. notice how close it is to the main wiring point on the mag. If that hole had gone through more I would have had burnt wires in a very difficult spot.

I made a little heat shield - which works well - I needed it as the ehaust gasket has blown twice more.

Non standard electrical additions; a SCI tachometer. which is a very nice analog instrument. An EGT meter for keeping tabs on the burn temperature, and a 12v accessories plug inside the glove box which I wired direct to battery via 15Amp fuse - Overall, the Skipper electrics fitted into the LX frame with ease.

I made a few mode little modifications, replacing the instrument running light with a red lens and LED coming from the regulators charge warning circuit. That was a standard feature on the Skipper.

The standard exhaust incorporates a catalytic converter (it gets super hot and has a lot of weight in it) and from what I have read - that is highly restrictive on performance. I've got my eye on the racing exhaust from SIP - its design and expansion chamber look perfect and the muffler sits underneath so it might be a good fit on the LX frame. Maybe one day.

I like the crisp exhaust note sound of a 2 stroke scooter, I like the rush of the power band when it kicks in and the seemingly endless ability to keep reving higher. I whish Piaggio would produce a factory 150 2-stroke (auto) in a classic frame but it's never going to happen. The downsides are that 2 stroke engines waste fuel and have higher emissions than 4 stroke.
Look out for me if you are heading to Boreen Point scooter rally this October. Scoot safe.


Ride every day.

The riding lights switch on the right leg shield. The manual choke control on the left thumb control.

Vespa LX150 2T

Fantastic write up and job well done. I always appreciate an illustrated write up with pics.



The only thing I think you need to do is paint the transmission cover black as that is the only eyesore on a beautiful Frankenbike.

Yeah, real nice! I agree with VEZPA, the tranny cover needs to painted. Awesome job!

Totally & utterly barking mad - I love it!!!

Excellent write up, many thanks for making the effort to take photos & post the thread.

Have you looked into how you can shorten the wheelbase or are you happy with the result??

fast i would like to now the top speed

Great project
Nice execution
Good result
Excellent write up

Thankfully no skippers in the U.S. so I can get that idea out of my head. Really really nice project. I like it. When ya gonna kit it?

Totally agree - black is the right choice, the transmission cover at the moment is bare metal - no paint whatsoever, just my oily hand prints..

Barking mad indeed - I was spending money on parts and thinking "I hope this all works or I'm in trouble with the wife" after I told her it was money in a good cause...

re. wheel base : The Skipper 150 2T engine / trans assembly is longer than the LX 50 2T by 5cm - it also has shallower pitch on it's two engine case mount point at the front - that's why it sat lower when attched into the LX frame. hence I fitted the rear suspension lifter.

With the wheel base being longer - this causes the rear wheel to hit up into the LX number plate trim assembly - I do not know how to correct that .....it is a problem I notice when the rear suspension loads up quickly and fully - i.e. hitting a pot hole in the road

I guess to make the wheel base shorter I would have to cut length from the engine mount swing arm ?

I can not say for certain how fast - I only have the original LX50 speedo and I am sure it is wrong It goes quickly.

If the wheelbase is staying where it is, to gain clearance on the number plate mount why not cut it off & fit the bolt-on assembly from a GTS? You will need to incorporate a new number plate light under the rear light but relatively speaking this is not too big a deal.

Looking at your photos I concluded that there was some margin for shortening the fabricated swing arm. Should not be too difficult to mock one up to see how far forward you can move the engine whilst maintaining front clearance inside the engine bay.

Good luck, whichever way you decide to go....

Thanks for your comments.

An expansion type exhaust is something that I have been dreaming about getting - the SIP one for Typhoon 125 in particular.... this bit of kit would unleash the engines potential. If anyone has tried that pipe system I'd love to hear your thoughts on it.

This engine can take a Malossi 172 cylinder - it's tempting, but where I live we get summer ambient temps of upwards 30c - so I fear I'd melt my air cooled monster pretty quickly with one of those bolted on. Much fun as it would be

excelent project & write up
ive been on with a project on & off for 2 years now, it a 4t skipper transplanted in to a vespa t5 ( with a hand made backend in a rat rod lowrider style) im strugling with the wiring. i bought all new components ie stator, coil, regulator ,cdi & a second hand wiring loom & still couldnt figure out how to make the motor spark. i took the motor to a shop with all the parts, the guy had it for 10 weeks then rang me & said he couldnt get it to spark so im at a standstill
im going to take it to a scooter shop i know in newcastle & see if the guys there can help me out, other than that im gona have to buy a crash damaged skipper that runs & transplant the motor & full electrics

Top idea - a 4T auto engine into a Vespa t5 frame ? ---- please post pics - I need to know more !!

If you are DIY - get your hands on a copy of the circuit diagram, the Hayes book has an electrical schematic of the Skipper 4T (ST model)
From what I can tell, the Skipper 4T electrical system came with an immobiliser which embeds itself between the ignition control unit, regulator / rectifier and the digital instrument display (the radio receiver side me thinks) Maybe one of these devices in your system is "armed" or locked. Because you've swapped different bits into your system, perhaps it's just ONE of the components that's immobilised? Look at the Piaggio part numbers in your ignition system, matching set?

If you are absolutely certain your setup is immobiliser free - forgive me if I'm suggesting something you've done heaps of times already.. Using a multimeter - measure all the connections in the ignition circuit... write down the results and compare each time you try something new. Chances are you might just find a quirky open or short circuit or poor ground connection. <insert> Long list of possible stuff.... All comes down to dull, tedious process of elimination.

Hey I just noticed, the Skipper 4T uses total DC power for its ignition, unlike the 2T that's got a single phase of AC coming from it's alternator to power the "whip, crack, bang" thingy (HT coil) - that means you need to have a good healthy battery in your setup.

The diagrams I am looking at suggest the Skipper 4T and Vespa LX-4T have a lot in common electrically - perhaps a source of parts??

Its been a while since I last posted.. Apart from spraying the transmission cover black, as suggested by some of you out there (it DOES look better in black by the way!) my scooter project has been reliable everyday transport.

There is always something that can be improved (as we all know, right?) One such problem with my scooter is an intermittent exhaust leak at the connection between the header downpipe and the rear silencer.

Last week I ordered the SIP manufactured replacement header pipe with 35mm inside diameter made from stainless steel.

A view of the original system


the original Piaggio exhaust header in place

A view of the Piaggio part during my initial build


the Piaggio part built in 1996

the connection end to the cylinder head Piaggio original part


piaggio part cylinder head connection

The SIP replacement part -35mm inside diameter


the SIP part - made in Germany 2010

another view of the SIP part


The SIP part

The part arrived yesterday - and I was instantly impressed with the quality of it's manufacture.

Thought I'd share these pictures of the original Piaggio header pipe and the vastly superior SIP component. The welding and connection is pure quality - even if it does not deliver the claimed 1hp increase in power the build alone is 88 Euros well spent.

I will be in the garage fitting the part this weekend.


notice the sealing weld is on the inside connection so that the facing plate is completely flat for easy of bolt attatchment- now thats good thinking.

Loving this mate - a bigger 2-stroker in an LX/S frame is my idea of a perfect modern. Good stuff

Exactly ! although my example scoot is far from "perfect"

I have a passion for modern Vespa -- It makes me sad to think that 125cc upto 200cc 2-strokes are never going be manufactured in this style by Piaggio..

so, thats why we make our own hey !

It is kind of sad that 2-stroke is confined to the smallest engines now (until the PX returns...again) because there are plenty of people who love them. The wife and I really enjoy the S50, and would like it even more with some poke.

Someday I'll chop it up a bit

Just so happens modifying an LX-50s is my next project. I have an LX-50s which I bought new in early 2009. I really adore the styling of this scooter but it needs a much larger 2 stroke engine to be properly 'special'

I recently got my hands on a 1996 Piaggio Hexagon - it's the "scoot with a boot" styling is the type you either love or hate. I guess the designers at Piaggio where munching disco bickies when they dreamt up the king and queen seat.

Anyway it's whole lot of scooter as cheap as chips. The 150cc liquid cooled 2 stroke engine is the magic.

So I am going to take the engine from a 1996 Hexagon and build it into a 2009 Vespa LXs - mounting the radiator will be tricky, but I not impossible (I hope)


on the left my seldom used Vespa LX-s 50 2t. The blue LX is 150 2T

Piaggio Hexagon 1996 150cc2T

the Hexagon - one hellova scooter from the 1990's

It's got a boot !!

Good luck with the new project! Kudos on the old project. 8)

Good luck with the new project! Kudos on the old project. 8)