Writing XTR Pepo and moped in the same sentence is not something we’d usually expected to be doing. Pepo’s custom motorcycle builds tend to have a race-bred edge to them and for many people, myself included, mopeds don’t fit into that equation. Regardless of that this custom Mobylette SP90 moped is XTR Pepo’s latest creation and it is as fit for racing as any of his other builds that have come before it.
For those who live outside of France and its surrounding countries, the Motobécane brand is probably as foreign to you as the places they were made. What’s probably going to come as a real surprise, however, is that during the companies years of operation, 1949 to 1997, they produced an astounding 14 million mopeds. Yes, 14 with six zeros after it. During the seventies, the French used thousands of Motobécane mopeds as delivery vehicles for their postal workers while in Pepo’s home country of Spain the Mobylette SP 90, or ‘Moby’ for short, was common for a very different reason. Due to relaxed Spanish road laws of the time, these mopeds could be ridden without a license, insurance or a helmet making them a hit with youths and anyone with little regard for their personal safety. With a power figure of only 2bhp riders weren’t likely to be breaking any speed limits, but as with anything with wheels and an engine it didn’t take long for people to start finding ways of making them go faster and of course racing them.
Pepo’s SP 90, named PTT after the French Postal Service, started out as a 1975 example but very little of that original bike remains. The most recognisable feature of his PTT Moby is its original pressed frame and the tiny low slung engine, but the similarities end there. As usual, Pepo took inspiration from classic endurance racers with this build. To recreate that look he has mounted an appropriately scaled racing fairing and tail section to the tiny moped and the original fuel tank has been stripped of its side panels.
During the redesign of his SP 90 Pepo used a selection of parts retrofitted from another Mobylette moped, the ‘Cady’. These parts, which include the front forks, cast wheels and swingarm, have been combined with aftermarket rear shocks to create the bikes racier stance. XTR clip-on handlebars and rear set alloy footrests place its pilot in a more spirited riding position and the speedo has been replaced with a Motoplat rev counter since on this bike engine detonation is probably more of a concern than excessive speeds.
As for engine performance, Pepo has increased the bikes power figure by 400%. While that may sound like a lot we are only talking 2bhp up to 10bhp, but all things considered, that increase is sure to deliver a very different riding experience. To generate this figure Pepo worked with a local moped race tuner (yes there is such a thing) who bored the engine up to 70cc, worked the intakes and lightened and balanced the crank. The original carb was also replaced by a 16mm Amal, the flywheel is a lightweight aluminium item and that beautifully made exhaust hails from Metrakit racing.
When it came to choosing a colour Pepo paid homage to the French postal service once again by choosing a yellow scheme inspired by the bikes they rode. The PTT may very well be the least powerful bike we’ve ever seen from the XTR Pepo workshop, but that certainly doesn’t make it any less appealing.
During the 1950s, under the leadership of racing engineer Walter Kaaden, Motorenwerke Zschopau GmbH, otherwise known as MZ, developed a breakthrough exhaust system known as an expansion chamber. Unfortunately for MZ their…