[NerdspeedTopic starterBerichten: 9]

Just a further update…. During the last year, I built (with some friends help of course) a custom subframe for this bike. Then My friends went absolutely nuts creating a custom exhaust pipe.

[NerdspeedTopic starterBerichten: 9]

Start calling European bike shops.

[NerdspeedTopic starterBerichten: 9]

I suspect there will be a motobrata or a fabrizmatic pipe in your future

[NerdspeedTopic starterBerichten: 9]

awesome. Thanks for the info!

[NerdspeedTopic starterBerichten: 9]

Thanks for the comments! The bike is a 1980 Vespa Si and it does have the stock monoshock that came with it. The custom intake was a lot of fun to put together, but installing it in the subframe required considerable cutting. A aluminum support strut has been installed to provide proper rigidity. I’m using a 63cc Polini Cylinder which has been ported and modified. Currently, the performance is very poor. The carburetor -a Tillotson HL360- is designed for 80-100cc Karts and needs to be adjusted for jetting and proper fuel pumping. Additionally, I’m using 17″ wheels along with the Malossi overdrive gear set, so the bike has very bad acceleration. The Polini Cup class I race has an ‘open’ qualification, so you can run any cylinder under 90cc’s on any moped, provided it originally had pedals and no manual shift. Currently, Honda Hobbit/Caminos and Derbis are the fastest machines, but the Vespas aren’t far behind. I have until April to get Plan B up to race speed. Here is the current port map:

[NerdspeedTopic starterBerichten: 9]

Thanks for all the useful information everyone.

Piet30- Does the simonini have clearance during turns? I’m not that concerned with riding over bumps since this will be mostly a track bike, but hitting the ground while turning would be a deal-breaker.

The reason for the big carbuetor (Tillotson HL360) is because ultimately I would like to build an even more aggressive engine, either out of a vespa or Honda Camino. TerryDean and I’s teammate has built a Camino engine with a LC Malossi MHR cylinder for a Aprilia Scooter rated around 18hp. The racing in California has heated up the ‘arms race’ in building fast mopeds for the hardcore guys out here. We will have bikes on par with the fast dutch guys probably within another year or two.

My blog: http://team-nerdspeed.blogspot.com details all the development, but here’s a pic or two:

Intake, under construction


Port Map

Exhaust – 186.30°
Mains – 128.6°
Boost – 131.4°

Paint Job, under construction

TimoO_ I will definitely look at the yasuni pipes, but because I don’t have much time left, I’d prefer an exhaust ready made for the Vespa.

[Gebruiker]

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