3 topics, disc brakes, gs engine mods, searching

Hello, 3 topics for the Vintage Vespa public:

  1. Is it possible to add a disc brake to a Vintage Vespa with out changing out the fork?
    I thought I had seen a Rally or Sprint with a bolt on outboard disc brake. Is this possible? Anyone sell a kit to do it? Otherwise, what is the best way? PK fork? Where can you get a PK fork? What are the issues with that? What about ET2 fork, will that fit in a Vespa Rally? How difficult is it to put a Lambretta fork in large frame Vespa? What do you reccomend?

  2. Are there any engine mods for a Vespa GS 150 available? I have a custome exhaust and an AC stator but other than that my GS is pretty stock. I have seen a few 12volt conversions, has anyone tried the new classic Vespa 12volt conversion from ScootRS?


Says that it could work with a GS 150. What I am really interested in (besides the 12volt conversion) is a carb and manifold replacment. This seems to be a real weak point in the GS 150 engine. Any one know of manifold that would fit, possibly with a reed valve? What about carbs? Most performance carbs available are side draft, so I am not sure how they would work. maybe with a custom manifold. Anyone seen any radical GS 150 engine mods???

  1. Is there a search page available on this site in English? Does the search page even work? If gives me an unknown error.


Original von Li-Ralph:

The fork can be replaced with a PK. Fits right on.

It fits right on if you don't include changing the bump stops,adapting the steering lock,adapting the fork top to allow the mudguard to sit properly and losing the correct look.


The stator plate is different on the GS 150-serie. If you should convert to 12 volts you must change the magnetos on the excisting plate and machine the plate down some There is a scooter shop in East London that does this. I cant remember the name. The ad in scootering is a picture of a GS 150 from behind whith a passenger sitting on sideways. (Scooter works?). I asked ScooteRS i Vietnam about the conversion and they said it does not fit a GS 150.

The fork can be replaced with a PK. Fits right on.

[:D] Slow down.

Firstly,the tidiest and easiest conversion I’ve seen is available from Worb5 for the Rally/Sprint range.

I don’t know if this will work on your forks but contact Andi at Worb5 and he should be able to help you.

Secondly,I’m no expert on the wide frames but I know of a German or Italian lad who runs a piston porter with a Pinasco 177 barrel.I presume this was the old twin induction item which would mean a reed valve on the barrel and a change of carb.That won’t be easy to find these days.

I would suggest joining here.

As for your ignition I don’t know.I do know that if you use the Vespa varatronic then you will need to use a PX crank.Remember,if you choose this option you will need a modified PX crank as the piston ported motor uses a full circle system as with a reed valve.

I hope this helps a bit.