Feature Scooter: Harnessing Wild Horses
Martyn ‘Drakey’ Drake, who owns and runs Anglia Scooters, set himself a goal of building a Vespa with an engine that produced 50bhp… and he did just that!
For some – a few in comparison to those whose dream targets are never attained – realising them is merely a stepping stone en route to the next target. Martyn ‘Drakey’ Drake, who owns and runs Anglia Scooters, England’s most easterly scooter shop, is one of the aforementioned achievers. He set himself a goal of building a Vespa with an engine that produced 50bhp (brake horse power being the definitive measurement of engine power), not for any other reason than to tick it off as an aspiration attained.
Grabbing the Grail
Needless to say Martyn indeed fulfilled his goal during the latter part of 2020. He takes up the story, from where the quest began through to accomplishment, with some insight on to how he got there. “I initially bought the scooter off a guy from Clacton about eight years ago and I think it had a 125 motor with a 166 Malossi kit fitted. I never even started the engine as my intent was to have a cheap scooter to test products and build different engines. To start with I ran a 172 Quattrini set-up which would keep
up with most road-going scooters but after a while decided to push the boundaries and build a large-block motor. First set-up was a Malossi MHR 221 on Pinasco casings. Things were always a struggle with these casings, maybe I was just unlucky but as soon as I cut into them and broke the surface there was major porosity which is never a good sign, especially as they needed to be welded so I could do what I wanted to do to them. I seemed to spend most of my time chasing air leaks through the casings but in between leaks had a good few runs with the MHR kits with various set-ups producing between 44-47bhp but never reaching the magic 50! So next stage was to try the new Malossi VR-One reed-valve casings... and what a decision that was. No welding was required and the casings had no porosity at all... result! So to go with these new casings a 64mm stroke Kingwelle reed-valve crankshaft too. Now maybe I was just unlucky again (as with the casings) but the crank lasted about 60 seconds before it twisted and let’s just say their customer care and product warranty wasn’t what I was expecting. I was back to square one.
“Months passed, a few empty promises and false hopes then I noticed SIP were producing their own range of crankshafts. Decided to go for the 62mm x 127 bell shaped crank designed for the Quattrini cylinder kit but I was going to run it on a MHR so ordered a few packer plates at the same time too so I could raise the cylinder to compensate. Multiple runs later with different set-ups, I was still in the low to mid-40s bhp, time for a rethink. On reflection, and to coin a phrase ‘you can’t beat cubes’, I decided to get some more ccs with the help of a Quattrini cylinder kit. Running with the 62mm x 127mm SIP crankshaft (already fitted) this was going to be an easy upgrade, giving me 252cc. The casings were already matched to a Malossi MHR but they were close enough for a test run. An hour later I had rattled the exhaust port out a touch and cleaned up a few rough bits here and there on the cylinder. First run and 45.5bhp! That’s a nice place to start. Top end was then off and on another five or six times, tweaking a little bit here and there, raising and lowering heights and gaps, until finally it broke the magic 50bhp figure.
“After contacting Martin Silberhorn at SIP they are very impressed with my results too, using my comments and praise as an endorsement on their website for their crankshafts. There is no intention of putting these engines to market. The fuel consumption is like a Third World debt (fuel flow is so great the inlet manifold condensates within seconds of running the engine) and every component is under far more stress than it was probably ever intended for; so engine life expectancy probably isn’t great either. Which brings me to operation de-tune to try and make it road friendly. So far it is only down to 48bhp (I
don’t get a lot of spare time) but it isn’t quite as ferocious. I need to reduce the carb size and fit a tamer exhaust too, which should put it in the low to mid-40s and back to being a less frantic ride. In its current state (48bhp) a fourth-gear top speed run is hitting peak power at around 98mph.
“What’s the big deal, you may well ask? Well, it’s just a personal thing, a bucket list really; I always wanted to get a Vespa to 50hp, now I have, so that’s a tick against that challenge. Pipe Design actually does a more powerful exhaust than the one I’m running but I like the spread of power more on this one and peak revs are a lot lower too and I never did match the cylinder to the casings so I always had a bit up my sleeve if it was needed.”
The next summit to ascend
After sharing the story of the whys and wherefores of his triumph, Martyn had a few reflections to add... “Building a 50bhp Vespa was something I had in my head and when I eventually got there I experienced a real sense of achievement. Looking back at what went into getting there, a couple of things come to mind. Deciding to go with Quattrini was the right call, going down that route took about three weeks, which could’ve saved me ‘wasting’ 18 months. Again, looking back, I wish the (50bhp) dyno
graph was better visually, purists won’t like how it appears. Though it wasn’t for them, I did it as a personal thing, for myself. The 50bhp Vespa engine is being de-tuned to make it more controllable for road use; as it was, the power-band was terrifying. Another exhaust may be a better option, but that said, I’ve always got various jobs on the go, so it’s not always viable to have a play around on my own projects, as it’s finding enough time to accommodate them. Now I’ve hit my target of a 50bhp Vespa, I’ve another equally expensive personal aim in mind, a 50bhp Lambretta!”
Words: Sarge
Photographs: Martyn Drake (Anglia Scooters)