Modern Vespa

Four years ago, I started to take apart my '76 150 Super to get it stripped and painted. The project didn't progress!! However, I have now decided to put in back on the road in it's original factory condition. The paint is Piaggio code 580 (described as beige but it's more like a mustard yellow). It has a number of battle scars and bits of surface rust, but the bodywork is remarkably dent free. There's absolutely no filler or post-factory weld. I'll be using whatever products I can find to keep the rust at bay, and I may even touch up the beige if I can find a good match for 38 year old paint.

The engine is pristine (later 3 port VBC1M). I've decided to put it on the shelf so that the scooter can be returned to factory at any time in the future. I am using a surplus PX150 engine, which will give me 12v ignition, EFL gearing/cruciform and 10" wheels. I decided to go 10" for the gearing and because I like the look (others disagree). With a PX rear shock and a 26mm spacer, I hope to achieve the 'squat' Rally 200 stance at the back.

I have a new DR177 kit which I bought five years ago and never used. I'm going to use it for this build because I want to experiment with tuning. Some people have altered the DR cylinder transfer ports to match the Polini, but I will be using a Pinasco 177 base gasket as a template. I am a Pinasco fan, so if this all goes wrong, I'll dig deep and buy the Pinasco kit, knowing that my cases are already matched. Conscious of the DR's inadequacies, I will be using Grand Sport rings (still 2mm but stronger) and a Polini 177 head. A 24/24e (original Dellorto) and SIP Road 2.0 Sport will be used. I decided against the full Grand Sport piston due to cost. Let's see if it was a good decision!! The aim of this engine build is to get good usable city power on a low budget, but I suffered a drunken internet buying accident and now have a Worb 5 flowed crank. This may prove a bad match for the other components. Anyone care to comment?

I will report my progress in this post, as others may be interested in how it turns out.

Here is the scooter at the beginning of the project, still on it's 8" wheels. The dark patches on the floorboards are where I brushed on some rust stabilizer. Trouble is, I was over generous with it, and now I need to try and get it off the surrounding paintwork. There were only a couple of small patches of surface rust where the paint had chipped. The original plan was to get it blasted, so I wasn't careful at the time.

If you already bought the 24/24 carb, I guess it will be ok, but the 20/20 will work fine. Some people have a hell of a time getting the 24 carb set up right so I hope it works out for you. As far s the crank goes, I have never used one, so I can't comment, but do a search as plenty other people on here have. Going to 10 inch wheel is heresy to some but it will enable you to run a performance pipe with enough clearance so you don't grind it on the bumps. Good luck with your project.

@Tierney The 24/24e was on the shelf, so I'm using it with this engine. I thought I had warped it 15 years ago, but it seems ok. Let's see how it behaves. I know that 10" wheels are not to everyone's taste, but I did want the extra clearance and the Sprint/Rally look at the back. It's the front that can look odd with 150 Supers. I'll post a picture when it's done and see what comments I get!!

I like the 10's too... the guard looks different when compared to a Sprint or Rally, but I don't mind. Crank sounds like it will be fine.

Welcome swa, nice scoot.

We have a 76 also, basically stock, which we're itching to tear apart, but the engine's running too well at the moment to mess with. Real workhorses, Supers.

Putting the original engine on a shelf and playing with a substitute is a great idea. Why didn't we think of that!?! Thanks!

Personally we'd keep the 8's ... they're what make Supers unique... but of course do what you like.

Looking forward to seeing your progress.

Well, I bought a Dremel a couple of years ago, so now's the time to do something useful with it. The DR177 has the same transfer ports and dimensions on the base of the cylinder as you would find on a stock 125/150 three port. However, once you Dremel out the thin 'shelf', the ports look very different. First off, I used a blue Sharpie pen to mark the Pinasco port shape, using the base gasket as a template. There is also a line up the cylinder spigot that is hard to see, but I also wanted to widen the window. You can see on the other side I've already had a little Dremel play! The piston will be modified to match.




After the bulk of the grinding, this is one side almost done. You can see how removing the 'shelf' has exposed the full port in the cylinder. Still some finishing to do. Luckily I inherited a comprehensive set of engineering files from my grandfather.

Top down view of the DR177 with both sides done. I left the third port alone to match the Pinasco porting. Unfortunely the Dremel slipped and I have a couple of slight scratches on the cylinder base. Hopefully this won't be a problem, but a this smear of

I guess the photo comments field has a character limit. I tried to point out that I slipped with the Dremel and scratched the gasket surface in a couple of places. I'm hoping this won't be a problem, but a thin smear of liquid gasket may be required to ensure a tight seal

The cases are late PX150 (2005) and have pretty thin walls around the transfer ports, particularly on the clutch side. To be on the safe side I used a bit of chemical metal (like the famous JB Weld) to give me more material to play with. As it happens, the Dremel only went through once, exposing a tiny patch of the chemical metal. It just goes to show how little material there is on the later cases, even when matching a relatively mild bit of cylinder porting.


Here is the clutch side. The little dark patch is where I exposed the liquid metal. Good job I put some in!

The case matching took longer than I thought, but I got there in the end. The picture in the post above shows the clutch side about half done. The Dremel didn't make it through the flywheel side, but the port wall must be pretty thin in places.

Next up, I installed new 'performance' bearings (SIP) and Malossi seals, having been happy with them in my PX225. Had I stuck with the stock crank, I would have left the factory bearings in place, but with the Worb 5 crank, I decided to go 'belt and braces'. In the future, if I decide to swap out the DR for a Pinasco 177, I won't need to split the cases. That's the theory anyhow.


The Worb 5 flowed crank, waiting to receive the fly side inner bear race.

Lovely piece of kit and it went in smoothly enough. It was a tight fit and it didn't spin quite as freely as I had expected, but I wasn't too concerned. The oil seal creates a certain amount of hold. It seemed good with the clutch torqued down to spec, the crank probably being pulled an extra couple of millimetres in the process.

I matched the piston skirt cut-outs to the wider cylinder spigot windows. The GS rings are the same ones that some people use with Polini 177 pistons (63mm). You can see in the picture that although they are 2mm fat rings, they are chamfered to approx. 1mm where they meet the cylinder wall. Probably not as good as having the complete GS piston with thinner rings, but a good compromise. The DR kit uses an Asso piston so can't be that bad. Malossi uses them and my old Lambretta 175 conversion piston was an Asso. That was a quick and reliable scooter, but I dare not say how long ago that was!!

Well, the next stages were nothing special. The Dremel was used again on the case and carb box to suit the 24/24e, but I did not touch the inlet itself. I know that Pinasco recommends extending the inlet by a couple of millimetres front and back, but I decided against it.

Having put the cases back together, the cylinder and Polini head went on, followed by the carb box and carb. I used some Naraku M7 cylinder head nuts, which can be torqued down tighter than normal (16 lb/ft in this case).

Next up was the SIP Road 2.0 Sport. I never expected such a struggle to get this thing on. Compared to the BGM BigBox on my 225, the SIP Road is a long way behind in terms of fit and finish. Added to the very apparent difference in quality, you cannot get a wheel on or off with the pipe attached, not even with the tyre deflated.

Engine back in, cables connected, and front end converted to 10" wheel. I think it looks pretty good and it certainly has some patina going on.


Scooterists from East Riding may recognise the scooter. I bought it from a chap in Bridlington some eleven years ago.

Looking good Swa45. If you have a look at the tips and tricks thread I think there's a couple of remedies for the twin pipe SIP road. But they certainly involve cutting/welding/bending.

Love how this came out. It looks just SUPER! I especially like that you didn't feel compelled to repaint it to make it even 'better'. Also, I just rechecked the dates of your posts and damn, you are a fast worker! I think it's time for you to start looking for the next one now...

@V oodoo Thanks. I did this over the course of two weeks, but posting kind of happened all at once and at the end. The PX150 engine had to come apart to install a 150 Super kickstart quadrant and the new crank/bearings/seals, but otherwise it was just a simple assembly. Dremelling ports and installing the Rally/Sprint front axle were the time consuming parts, just because I'd never done them before.

The bodywork just needed some TLC, once I had decided not to bother with a repaint.

That looks like very nice work!

So how's it run? Any issues, anything you'd do different next time?

The '76 VBC was DC for the UK market and of course 6v. I wanted the most straightforward route to 12v, given the VLX2M engine swap, but I was resistent to a complete loom replacement or any other deviations from factory. Therefore I decided to stay DC and just use a new 12v battery and a 12v four pole rectifier/regulator.

After hunting everywhere for a battery with the exact same dimensions as the old 6v, I finally settled on the Motobatt MT4R. It is a sealed, maintenance-free battery, which fits onto the original VCB tray. However, it is not tall enough to use the stock clip/clamp, so I will need to find a solution.

The new rectifier/regulator is sold for small, modern scooters, but it has the requisite AC in, AC out, DC out and earth connectors. It also uses a single frame mount which meant that I could use the existing mount where the old 6v unit was. The PX type uses two mounts and is much bigger. I did not want to drill an extra hole in the frame, again with future reversion to factory spec. in mind.

Red cable (new) from battery (+) to DC on the rectifier, and split off to connect (via a 12v 7.5A blade fuse) to the brake light and horn (green and blue wires in the loom). This DC circuit also powers the parking lights (front and rear on a UK market VBC). Rectifier earth and battery (-) to earth on the frame. Easy.

Blue cable from PX stator to the AC (in) on the regulator, using the existing engine-side junction box and some sleeved blue cable to the battery side, and using factory frame holes and grommets. The black from the stator follows the same path and connects to the same frame earth where the rectifier is mounted.

Finally, a new yellow cable from the AC (out) on the regulator was connected to the yellow AC feed on the loom. This will power the rear light, main headlights and hopefully the speedo light.

I installed 12v bulbs all round, including a halogen 35/35 watt bulb with BA20D fitting for the factory SIEM headlight. I also have a 12v 25/25 watt traditional bulb, in case the halogen creates too much heat. I may need to source a different bulb hold and/or headlamp to use the halogen, or maybe the regular bulb will suffice. The speedo bulb (tiny festoon) was not easy to source and even the one I did get from Beedspeed is not the good fit that I wanted. Let's see if it works!!

The horn is the original one (DC) and it works really well. It's as good and loud as my PX. I don't fully understand if the horn is good for 12v or if I will need to get a different one. I hope it's ok.

The brake light and parking lights (DC) are good and the main lights (AC) are lovely and bright, front and rear. Even the speedo light works a treat with it's new 12v festoon bulb.

I am assuming that the rectifier is trickle charing the battery.

To recap:

VLX2M base motor
Worb 5 flowed crank
DR177 top end with Pinasco 177 transfer porting
Matched crankcases (see above)
Inlet matched to carb box (24mm carb)
Grand Sport 63mm rings
Polini 177 head
Dellorto 24/24e
45/140 idle
160/BE3/120 main stack
SIP Road 2.0 pipe
21/68 primary gearing and same EFL gearbox as P2
Cosa 2 clutch (no mods......yet)
27 degree stator timing
Kytronik SmartBooster on curve 8 (retards by up to 12 degrees)

I am running/breaking in this engine, so I have not opened it up yet. Early observations are that it pulls away much like a P2, but it has a power band somewhere around 4000 RPM and it suddenly takes off. No idea about top speed at this stage, but as a PX150, it topped out at an indicated 62/3MPH. The gearing will not allow for high speed freeway cruising, but I have the Pinasco PX225 for that. I imagine that once it is broken in and I can give it some, it will be a lovely old wolf in sheep's clothing, with a top speed dictated by the gearing and a reluctance to get above 7500 RPM. It is a DR177 with a SIP Road 2.0 after all.

Update: The standing start seemed a little sluggish, so I reverted to 55/160 for the idle circuit and upped the main to 125. What was a whitish brown spark plug (NGK B7HS) after a good ride has become a dark chocolate brown, so I've gone from lean to rich by the looks of it. Some more iterations to try before I'm happy. I have B8HS and B9HS plugs to try.

I also installed a PK XL lightened flywheel and set the Kytronik to a more conservative setting (retards to 18/19 degrees up the rev range). Now the take off is much better and smoothes out that sudden burst of power at what I'm guessing is around 4000 RPM. In neutral, the lighter flywheel makes it rev much more freely.

Still running it in, but it's had five brisk runs of approx. 10 miles, with a good mix of RPM variation, gear changing, hill climbing, and standing at junctions/traffic lights. With this many full heat cycles, some would say that it's already broken in, but I'll keep it sensible for a few more local trips.

Any issues with the cut piston skirt in this setup?