Scootering, number 123, January 1996 - Sexual fantasy Lambretta street racer

What do you think it's like to ride a 30 horsepower scooter on the road? Thirty horsepower might not sound a lot in bike terms; plenty of new unrestricted 125's can do that, but they also do significantly more than 100 mph. Thirty horsepower on a dyno is after all half as much power again as the average TSl, three times as much as a standard TS and nearly four times the real output of a typical GP 200 (eight and a bit hp). With only two more horsepower Mike Davis' 1995 racer reached 117 mph so it's fair to say that a full-frame GP with nearly as much go isn't going to hang around. Suffice to say that it doesn't.
What makes me laugh is how relatively low-tech the M.B. Development's motor is compared to many of the other quick scooters of the past and present. Not here will you find any water-cooled heads or barrels, no welded and enormously ported transfers, no huge reedvalve conversions or made to measure exhausts. This engine looks like a run of the mill TSI, it just doesn't perform like it.
The scooter belongs to Rob Henson from South London, who was kind enough to let me have a go on it in the streets where he lives, at night. So what's it like to ride a 30 hp Lambretta on the road, in the city, in the dark?
Well, it's a bit mad really. South London, unlike North London is not blessed with any decent dual carriageways (presumably because very few MP's live there and therefore it ranks pretty low on their transport priorities), so the test was confined to some wide residential streets with as IitP1e traffic as we could find.

Acres of chrome and engraving mark this clearly as a mid 80's custom.

Rob's scooter starts easily enough but is uncomfortable two up because of the squareback seat as we ride round looking for a suitable runway. I try not to give it loads to begin with so: A) the engine has some time to warm up, B) I don't loose Rob off the back when I don't know where I'm going, C) his neighbours don't start a resident's committee on noise pollution.
To be honest, the exhaust note from the MB pipe and the power of the engine at low revs are all quite acceptable for pottering about. There's not a lot of power out of the powerband, but still enough to fend off any manic Pizza Delivery boys who might want to take on 'the old sixties bike wiv two geezers on if. As we look for a suitable strip of tarmac we only get shouted at from one window.
That is the difference between a shop built scooter, and one that's been properly ported but set up fn the back garden. In years gone by a tuned scooter would have a razor sharp power band; spluttery at low revs and then take off like a scalded cat just because the carburation and ignition were that far out. A properly jetted scooter was one that could make it down several miles of dual carriageway on full throttle without seizing. Who gave a toss about bottom end power, it was only ever used on full throttle anyway.

It looks like every other TS1 in the engine deptartment only it isn't. The average TS1 produces only 66% of this power though.

Thankfully the day of the dyne has dawned and Taffspeed regularly find whole horsepower and dollops of bottom end grunt are there for the taking even on loony tuned machines, just by setting them up right. Rob's bike is very close to correct but not perfect. Free of a passenger you potter along out of the power band and open it up. In a brief split second all the following happen the revs and power rise slowly still out of the powerband. At the point where a normal GP200 would be screaming for mercy, the engine gives a little cough (more of an Ahem! actually) and Sexual Fantasy swaps it's high heels for trainers, doubles in volume and suddenly it begins to bugger off up the road like there's no tomorrow with the front wheel in the air. And that's in second gear.

Semi-naked lady and engraved horncast, truly the product of a young scooterboy's imagination.

Third gear picks up perfectly cleanly off the end of second and by the end of third I'm doing about 80 mph and running out of street. There is absolutely no point in using fourth, the motor thrives on revs and shifting up below 70 mph will almost certainly he an anti-climax but the claimed top speed of over 100 mph is entirely likely. Thankfully the hydraulic front disc conversion works better than mine and I can stop before the main road junction ahead. This would all be much more fun if the pedestrians and cars crossing our test track had any idea that the little square headlight coming towards them was moving about twice as fast as they guessed.
At night, speed always seems a much more intense sensation, and never more so than on a scooter (except maybe a go-kart). The GP sports essentially standard running gear apart from the Bitubo back shock and the hydraulic brake and that makes stopping and riding on irregular surfaces a bit of a laugh.
The bike itself is basically a thoroughly used mid-Eighties custom - lots of chrome, engraving and a mural of a tart wearing minimal clothing on the legshields. A popular theme at the time as I remember. Now, over ten years later it's starting to look a bit bedraggled and a little out of date which is why Rob is looking to build a new and improved bike to put that lovely engine in.
The engine itself is based on a milder version of Mike Davis' multi-race-winning barrel of the 1994 season. The top end is a steel-lined TS1 with modified boost ports and running a Yamaha piston. The crankshaft is a Rotax rodded 60mm stroke item attached to a plain old AF electronic ignition system. Remarkably the gearing is only standard LI 150 albeit with a 16 tooth front sprocket to raise the gearing and a 6-plate clutch conversion to cope with the extra power. Exhaust is the ultra revvy MB 2 pipe.
For now though it can stay as it is: a very fast and very entertaining reminder of days gone by.
Sticky

Rob Henson is an art student, but being an unconventional kind of guy, instead of doing nothing at all, or starting a band, he actually does some painting and his originals are already fetching good money.

SCOOTER DETAILS
Name: Rob Henson.
Age: 27.
Job: Painter Artist.
Name of scooter: Sexual Fantasy.
Scooter model: GP Innocenti 200.
Date purchased: 1985.
Inspiration for building scooter: Love.
Time to build and by whom: Me and about 30 dealers.
Frame modifications: Battery tray cut off.
Specialised parts: Whole bike.
Engine: Iron linered TSl barrel, Stage 4 Yamaha piston, Li 150 gears, Rotax Rod, 6 plate clutch, electronic ignition.
Carb: 34 flat Dellorto.
Exhaust: MB Developments.
Top speed and cruising speed: Top - 100mph+, Cruising 85mph.
Paintwork and murals: Misdemeanours 1984, original cost I don't know, but it cost me £400.
Engraving: Agius, London.
Chrome: London Chroming.
Cost: £900.
Anything you would like to add: Thanks to Mark, and my girlfriend Chrissie for her understanding.

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