I’ve moaned for long that modern sportsbikes are far too fast to ride ‘enthusiastically’ on the road. Even an entry-level 600 gives you 100 bhp at the rear wheel, and most of us don’t have the skill of Lorenzo, Rossi, Stoner et al. But low-powered bikes are slow, right? Well, in the car world, the Lotus Elise isn’t slow - it doesn’t have much power but makes up with light weight. I wanted a bike like that. I don’t need to go 170 mph, so light weight was key.

The answer to this question existed decades ago - the 250cc two-stroke sportsbikes like the Aprilia RS250. Emissions legislation killed them (and the GP racers that inspired them) - and nothing has filled the gap. The lightweight ‘fun’ bikes on the market are mostly supermotos. What if a sportsbike could be made that weighed 115 kg like a supermoto? It’d handle fantastically, and would only need half the power of modern 600 sportsbikes to accelerate like hell. A modern, 4-stroke RS250, if you will...

Well, the racing community was already there - a Spanish firm, BeOn, is building kits to convert motocross / enduro 450cc bikes to a ‘race bike’ shape. Sounded ideal - around 60 bhp, 115 kg.

Martin Thrower in the UK imports these kits, builds race bikes and races himself. It just happened that he was building an Aprilia-based race bike for himself... all the others being based on single-cylinder motocross bikes... Hence I had to ask the question - How about a road legal version? I quickly acquired a donor SXV450 road bike, Martin found some genuine GP250 wheels (from Ratthapark Wilairot’s Honda), and Project GP45V was born...