27bhp PM Tuning Vespa Sei Giorni – Part 2 | TUNING
In part one of this feature, we rode this tuned 27bhp Sei Giorni and it is quite a beast. It’s fast, fun, able to wheelie and sounds angry. Just the kind of scooter we like at ScooterLab (see the short video below). This week, Paul Melici, the PM behind PM Tuning takes us through the shop’s handy work as they smoothed out that rear end, tuned the engine, fitted a 350cc throttle body, A Malossi V4 top end and plenty of other power-related and aesthetic modifications.
It took a lot of work and some serious dollars to make this 7th Day GTV what is probably the sharpest GTV in the country. Unless you know different?
Owner Adrian Maelzer, a demolition environmental engineer from London uses a stock GTS300 for most of his weekly commutes in and around London but wanted something a bit special for his Sunday rides, hence the Sei Giorni 7th Day GTV300.
His brief was simple, he wanted the best performing retro GTV300 possible, so a few days later a brand new, zero mileage GTV turned up at the PM works HQ for a full in-house custom treatment. Adrian wanted us to make the machine look more retro. Piaggio had done a half-baked job of the headlight on the fender and exposed handlebars but failed to address the rear end, opting to use the rather large modern stock GTS tail light unit.
VIDEO | A quick blast on the PM Tuning GTV
Tidy rear end
PM Tuning was tasked to carry out the custom build, starting by plating out the large void that is left once the rear tail lamp is removed. We custom made a plate to follow the original contours of the rear end in order to avoid using a copious amount of body filler in the process. This was then carefully rewired into the vintage Vespa style rear lamp incorporating a service grommet in order to make it all workable. Then we refinished the paintwork to match the matt green finish perfectly, the end result is how it should have been from the factory.
Adrian had already purchased some parts from Gerald Fink but the conversion was not going to be straight forward due to the fact that the larger 38mm ECU we were using was never configured for the ABS euro 4 machines. It required rewiring the pinouts on the ECU to achieve electrical compatibility.
Parts like the custom velocity stack were designed and made by PM as part of the build. A velocity stack is a way to virtually tune the air being driven into your intake, helping to produce more power and a cleaner more efficient burn.
The Malossi V4 cylinder head was gas flowed for optimum flow and the piston valve pockets machined deeper to allow for the extra lift provided by the tuned camshaft, careful modification to the decompressor shaft, and a match and blend to the larger CNC inlet manifold completes the head modifications.
Going faster meant the scooter would need to stop quicker too, so Brembo brakes were specified, a 4-pot caliper was fitted to the front with a twin-piston Brembo on the rear. We believe this is the first conversion of this type on a Euro 4 ABS machine front wheel sensor. Outer brake pad and front wheel offset modifications were required in order to get it all to work correctly.
Runner ST rear wheel
The rear wheel had to be changed out for a 13-inch Gilera ST item in order to accommodate the extra clearance required between the caliper and wheel rim. The ABS ring rotor was then machined back onto the rim for the ABS sensor to read correctly.
Before it left us the machine was dynoing in at 27.3bhp on a tight new engine, we believe this will end up at around 29bhp with a few miles under the belt. We hope to see the machine back at PM HQ in 1000 miles time for a full check over, to include valve clearances, transmission, oil/filter etc. and will get the opportunity to update the final results with another dyno run.
Words and photos: Paul Melici
Parts and mods
Malossi V4 head
Malossi 285cc kit
PM Tuning gas flowed head
Polini valve springs
38mm CNC inlet manifold
38mm ECU and throttle body
PM induction velocity stack
PM variator kit
Malossi torque driver
Malossi gear up kit
DR Pulley Hit clutch
Polini CNC clutch bell
Bitubo gas shocks (front and rear)
Brembo 4 pot- 30/34mm piston brake caliper front
Brembo 34mm dual piston rear caliper
CNC caliper extension brackets
Gilera ST125 13-inch rear wheel
PM Tuning Saw disc rotors
Black legshield trim
Black custom rear rack
PM Tuning carbon fibre sport screen (Runner)
PM Tuning carbon fibre fuse and header tank covers
PM Tuning carbon fibre rolling nut cover
PM Tuning carbon fibre linkage cover
PM Tuning CNC bar end mirrors.
Dark tint indicators lenses
Bodywork Plated/blended and refinished rear end with vintage lamp
New products always in development…