Love them or hate them, hybrid scoots are a marvel of engineering and this example by John Birch is one of the tidiest out there. Stu Smith caught up with John…
Having previously developed a show-winning machine, Yambretta veteran John Birch decided to take things up a level with his new project, so we asked Stu to find out more…
Sc: What was the inspiration behind this project?
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JB: “I got restless and found myself looking for another challenge. I wanted to see if I could develop a more modern machine. Having developed a strong friendship and working relationship with Yambretta aficionado Gary Hancock, who built the first Yambretta I owned, I knew I was always going to be on a good footing…”
Sc: You say you wanted to develop a more modern machine. Why have you stuck with the Yamaha 350 engine?
JB: “It may have been around a while, but in my opinion it’s one of the best two-stroke engines ever made so with that in mind it was always going to be the starting point for this build.”
Sc: What adjustments have you needed to make to accommodate the new running gear?
JB: “We had to start with some adjustments to the frame. Gary has his own jig and ideas which allowed him to plan the upgrades we had in mind. One of the fundamental aspects of this project was that we wanted to keep the look of the bike as close to the original full-bodied Lambretta lines as possible. This meant getting the engine in place without widening the body. With that completed, the side panels were discreetly stretched. There are the smallest and neatest cut-outs on them, which tastefully reveal the engine casings.”
Sc: Tell me about the engine spec?
JB: “The engine’s a mainly standard Yamaha YPVS 350 engine, which was completely rebuilt by racer and mechanic, Jonny Wilson. The fuel supply has been upgraded to a system designed and engineered by Gary. The carbs are twin Mikuni 28mil flat sides fitted with K&N air filters. It’s got a Zeeltronic programmable electronic ignition system, the six-speed gearbox has a Klicktronic gear shift and to complete the set-up the exhausts are mild steel Allspeeds, which have been modified by Gary and chromed by Dave at Classic Chrome in Hinckley.”
Sc: There’s plenty going on with the engine set-up so what improvements have you made to the handling?
JB: “The bike’s got 12-inch wheels fitted with Dunlop ScootSmart tyres. To maximise its stopping capability, it’s got disc brakes front and rear and the suspension has been upgraded with front and rear fully adjustable one-off items developed by Gary to suit the road and riding conditions.”
Sc: What other upgrades have you made?
JB: “Traditionally, this type of conversion has mounted the radiator behind the legshields which have been cut for ventilation. Instead, we’ve fitted the radiator under the bike, which continues the full-bodied Lambretta look and gives room for an inner-legshield toolbox. Gary’s hand-built a custom fuel tank, which holds 13 litres of fuel, and he also built the seat-base hinge which allows the seat to stay upright when fuelling up. The front indicators are on the ball-ends of the handlebars and the rear indicators are LED items discreetly fitted just above the number plate. Gary also built the seat base which has a custom cover made by Keith at Ken’s Customs.”
Sc: The Road Runner theme’s interesting; where did that come from and who tackled the paintwork?
JB: “Back in the day I loved the Road Runner cartoon. After my grandkids watched a couple of episodes, they also loved the character, so the choice was obvious. I applied all the paint myself and for me it was probably the hardest part of the project, which makes you realise just how skilled the professional paintwork specialists and airbrush artists really are.”
Sc: What advice would you give to anyone who’s thinking of starting a similar project?
JB: “Look into it properly, cost it out and have a target in mind. To get the best results don’t take any shortcuts, get the best specialists involved who’ll be able to give you the best advice and support. Most importantly, if you’re married make sure you get your wife’s permission first!”
Stu says:
John’s ridden Yambrettas for the last six years and the object of this build was to set himself the challenge of developing an upgraded, improved and more modern machine. Working with Gary Hancock and with the support of a team of tried and trusted specialists, the improvements and upgrades that have been made are impressive. Alongside that, on a more light-hearted approach, the theme of the paintwork brings in a cheeky feel to the bike and every time John goes out on it, Road Runner gives him the grin factor he’s always looking for.
Words: Stu Smith Photos: John Birch
Article originally appeared in Scootering Magazine March 2025. To subscribe and grab some Meguiars cleaning freebies visit https://classicmagazines.co.uk/scootering?offer=SCOME2026
