There are a few must-haves. The bike has to be an older, reasonably rare Yamaha. It must be possible to convert it into a sportbike with good handling. And it needs to look ‘factory’—complete with rear fender, if need be. Like this incredible XS850 inspired by vintage racebikes.
Maarten is one of those ‘amateurs’ whose work is a match for most professional builders. He kicks off his annual project in October, starting with a thorough test ride to check how his latest donor bike performs.
In the run-up to Christmas the bike undergoes a complete rebuild—mainly with OEM Yamaha parts, or homemade items like rearsets, gas tanks or caliper mounts. Nothing is left untouched: everything is altered, or gets fresh paint or powder.
Maarten built this XS850 triple for a classic street race in the Netherlands. He found a donor with a broken camshaft and worn out bearings, and built it up to factory-fresh specs. The process wasn’t without incident: a small screw from the carbs got stuck between a valve, which meant a total head rebuild and new pistons.
The electric start is gone, with just a kickstart and a small battery firing the bike into life. The Hitachi carbs have been reconditioned and now breath through K&N filters. Spent gases exit via an exhaust system from the Welsh company RVS.
There’s serious work on the suspension too. The front end is from a Yamaha YZF-R6, with a HyperPro spring upgrade for the forks. The brakes and clip-ons are from an R6 too, along with the modified upper triple tree.
Maarten has massaged the XS850 frame to accommodate the new gas tank, which comes from a Honda Bol d’Or—the droop at the rear of the tank being the giveaway. The tank is fitted with a double petcock and a classy Monza cap.
There’s more radical frame (and swingarm) surgery further back, where the twin shocks of the stock XS850 have been ditched for a new HyperPro monoshock setup. The rest is just detailing, but it’s also immaculate—from the matte grey powder finish on the frame and swingarm, to the discreet new wiring loom and the period-style fairing.
A classic case of form following function—and looking damn good in the process. And who can resist those iconic speed block graphics?
Images by Mark Meisner.