BUYER’S GUIDE 1994-2004 APRILIA RS250

What to look for:

Buying an ageing two-stroke is always a bit of a lottery, but going in with as much information as possible is always a good start. First of all, identify your RS250, as there are two generations, the Mk1 and Mk2. The Mk1 was built from 1994-1997 and is easily identified by the fact that its Marzocchi forks split the preload and compression adjustment between their legs, where the Mk2 carries these adjustments on both Showa forks. The Mk2 also has a wider front wheel rim (120/60 from 110/60) and a different fairing. With that sorted, you now need to focus on the engine.

The Suzuki VJ22 motor has Aprilia’s own barrels, heads, airbox and ECU, but it still suffers terribly from incorrectly set power-valves. If the valves fail they drop into the engine with catastrophic consequences, so always ensure they have been set up recently and aren’t gummed up with oil. Technically, the RS250 has 2500-mile service intervals, but in reality that’s not the case.

Try and start the bike from cold with the choke off. If it pings into life then the chances are that the choke is stuck on, which is something you can confirm by seeing if the engine feels flat and woolly on a test ride. The choke works by a plunger covering a kind of jet. It’s a simple on/off arrangement, so if the choke cable is wrongly routed or snagged the choke is held permanently on. Everyone knows the rule with highly tuned strokers – use fully synthetic two-stroke oil and the highest octane fuel you can, but also keep an eye on its cables, as they stretch over time and the RS250’s oil pump, carbs and power-valves are all interlinked. If one falls out of sync, then it can start an unwelcome chain of events.