The World’s Fastest Vespa?
What is Dry Lake Racing? Well if you’ve seen the movie “The World’s Fastest Indian” or heard about the Bonneville speed records, that’s basically it. Years of effort for a ride that takes only seconds, to get the fastest top speed on a salt lake over a timed distance. What you might not know is that we have our own Australian “Speed Week” organised through the Dry Lake Racing Association ( www.dlra.org.au
The first issue was that a Vespa couldn’t enter due to wheel size. The DLRA rules stated 14 inch rims or greater were required. Fortunately the DLRA have common sense on their side and members (of which I became #647) could submit rule changes. So I managed to get the rules updated to allow the humble Vespa to enter and become the first scooter to be officially timed on the salt lake.
The next problem was one that common sense governed couldn’t be overcome with a simple rule change. To enter, no mater what the wheel size, the tyres had to handle the speeds. Much research showed that the Sava MC16 tyres I already had were the highest 10 inch speed rating available, however at 150 km/h it wouldn’t be enough. Speed rating is a tested combination of maximum safe variables, being speed, pressure and load, so I took a long shot and contacted Sava and asked for what variables would make the tyres rated at 180 km/hr. Thankfully they came to the rescue and Sava R&D provided an email with the reduced load and increased pressure to allow me to race… game on! Note to everyone going faster than 100 km/hr on 10 inch wheels; check that the speed ratings suit your speed!
The next hurdle was building a sub-250cc Vespa capable of a 170+ km/h! This is real speed too, measured by timing equipment not by an optimistic Vespa speedo, and in the open air, unaided by cars breaking it up. To be serious, this is where Vespa folklore has to go out the window and science has to step in. I had been pushing the concept of Vespa Labs (www.vespalabs.org) over a few years, a wiki (shared website) where everything is up for criticism and test results are the only fact. So the “Dry Lake Racer” became a lab project, with notes public and the dry lake as the final test ( www.vespalabs.org/Projects/Dry_Lake_Racer
Step one was to not base the Vespa engine upgrade on typical 80’s tuning technology. It was decided to jump straight to a modern Kawasaki KDX 200 top-end. The KDX had a similar stroke (58mm), was water cooled, had transfer ports the size of your fist and also had a 240 big bore kit available (should more power be required). The Achilles heal however would be the Vespa gear box and cases, so the plan was to build up the power gradually to break the record and not the gear box (too often).
I was intending to build the engine myself with my own limited lathe/mill, however I asked a fellow Vespa Labs tinkerer, Jeremy Scott (a tool maker with awesome machinery and experience at his disposal) to mill down the cases to fit my design. He took a look at it and said “leave it with me”… within weeks he had redesigned the conversion. High quality welds, reinforcing to every weak spot we read about and a large touch of his engineering knowledge. The Vespa Labs Dry Lake Race Team was formed. I became “Chief Scientist” working out what needed to be done, doing the bits I could, and Jeremy, “Chief Engineer”, working his magic at getting the many tricky bits done and done properly.
Together we got the KDX head on and working beautifully, pushing through numerous problems. We used a Yamaha DT 175 flywheel and ignition, which worked great once we rewound it to work in the opposite direction (trail bike flywheels are on the clutch side). Water cooling was addressed with a custom radiator from Aussie Desert Coolers (normally hotrod focused). Jeremy strengthened the clutch to be 16 pin and banded, and balanced everything to run smoothly with the Worb5 full circle long-stroke crank.
One of the biggest issues was the gearing and matching that to power. To get to 170+ km/h we needed the lowest possible primary gear ratio, which was found in the Worb5 Malossi 24/63 kit. Even with that we needed to rev the engine out to 9,500 rpm and have peak power at that point. We also needed a power curve that allowed us to get to that power band.
The other major issue was aerodynamics, the faster you go the more air you need to push and the faster you need to push it. Speed is ALL about getting through air and most of the power goes to overcome drag. In fact the bigger bikes add lead shot to their frames to give greater traction on the salt just to push air. I calculated to do 170+ km/h on a standard Vespa frame we’d need ~35 hp at 9,500 rpm, so any reduction in drag, dramatically reduces the power required. In addition to that, the scooter has to be stable and I was worried that the standard Vespa profile would tend to lift the front end at speed. The front guard was removed, radiator fitted as low as possible and framework for under body fairings created. Also added was a custom screen, which is more aerodynamic than a rider and greatly improves performance as well as handling.
The project started in early 2007, we were almost ready for the 2008 meeting but that was cancelled due to rain. So you would think we’d be ready for 2009… well no. The salt recently has been very touchy, two years in a row it has been cancelled due to poor conditions. Jeremy and I were both flat out with work and we only had a few weeks notice that it was actually on! Unfortunately due to the short notice Jeremy couldn’t even go. The scooter was running but no where near the completed gleaming streamline speed machine we had planned (in fact I was still fitting bits on the salt just to get through scrutineering).
We had got to the point of testing the scooter out at a short race track (Broadford). There we had rev’d it out to 10,000 rpm in third, which is a very respectable 140 km/h. However rev-ing out in 3 rd th
The journey to the salt from Melbourne was a logistical exercise in itself; the lake is 160 km of dirt road from the closest town (Iron Knob). Graham Hadley from ScooterMarket kindly took the scooter for me and I (and the family) got there by hiring a 4wd camper from Adelaide. 1300 km and 3 days to get there but after months of drought, we arrived to find the salt was delayed by heavy rain that Saturday. The next few days were a painful wait for the salt track to dry enough to not be cancelled and thankfully by Wednesday we could race but only for 3 days.
The pit area is ~2 km out on the salt lake and driving out is a surreal experience. It’s a bit like dying and being transported to some form of motorsport heaven, everything is gleaming white, the concept of time evaporates and through the whiteness a Mad Max like camp appears. Though it’s the first time a Vespa has been entered, it fitted right in with all the other wacky racers. There were ~140 vehicles all based firstly on the owners’ style and secondly on being hotted up to ridiculous levels… postie bikes, a super-kart, big bikes from 50’s Vincents to 00’s Hayabusas, lakesters (aircraft belly-tank based cars), a VW, a taxi cab and special construction bikes and cars of all cc’s. Once through scrutineering my scooter took its place in the “motley queue” to be called up to race.
The first run we got was late on Wednesday. At Broadford the scooter handled like a dream, however this was our first run on salt, in 4 th st
The next run (Thursday) I decided to let the tyres down to normal road pressure. I am used to sliding around on gravel roads, so I thought as long as it felt like that I could fang it just through the ¼ mile timing markers and hope I wouldn’t crash. This time however I had a slight headwind and when I twisted the throttle from low 4 th
On the last run (Friday), the air was still and I wound it out early in 3rd and into 4th in time to hit the time markers in a good position. This time I got more power but failed to push through to higher revs. The last and fastest time was 132.29 km/h. By this time I was used to the sliding but the engine just wouldn’t perform well with the test pipe, unless it could get thought the 7,000 rpm dip (which sucked half the power). The last run was a few hours before the track closed, so there was no chance to try some bush mechanics and wire on the “secret weapon” straight pipe.
So no, not the World’s Fastest Vespa (yet), and only the fastest on the Australian salt by virtual of being the first and only; however it was a bucket load of fun and a great learning experience. Most importantly we raced which is 99% of the challenge and didn’t blow up or crash, so the scooter and I live to have another go in 2010. With the correct pipe, completed streamlining and a few planned handling improvements, we will be getting a 160+ km/h next year.
However, as mentioned 170 km/h is fairly standard for a motorcycle and a few motorbike people thought the same. #787 Barry Parsons now holds the MPS/G 250cc record at 196.155 km/h, a speed definitely unachievable by a mere Vespa. Next on the Vespa Labs drawing board is a 1951 Vespa Siluro based streamliner to take our engine. There is no current record for a 250cc streamliner, so any speed will set the record but we’ll be aiming for at least a 125 mph license (within 10% of 200 km/h).
The DLRA “Speed Week” was a fantastic event and met a lot of great people. I’d specially like to thank the #374 Jarman/Stewart lakester team (Peter Quick, Grumpy, Dr. Goggles and Rev. Hed Gash) who took me under their wing, their shade and showed me the ropes. An extra special thanks to Graham Hadley for taking the scooter and Peter Quick for running support crew and taking pictures. And of course a big thanks to Sava for making it possible for us to race in the first place.
Paul McIntosh + Jeremy Scott (Pictures with an "_" at the front are by Peter Quick)
VespaLabs Dry LakeRace Team