POWER PLAY
The UK’s best 47bhp nakeds go head-tohead for A2 crown
Riders often get confused between how power and torque translate to an engine’s performance. Although they are intrinsically linked, the simple way of thinking about the differences between the two is to imagine a wall. Power is how hard you hit the wall – torque is the force you use pushing through it. Why does that matter? Well, if you are restricted to an A2 licence, you are only allowed a maximum of 46.9bhp (35kW), however you can have as much torque as you like in a bike of any capacity. A legislation that has resulted in
the three different routes taken by the bikes that we are riding on the MCN250 right now. Through an ECU remap and modifications to the airbox (which costs £120 plus 1.5 hours in labour), Honda have chopped the CB650R’s power down from 92bhp to an A2legal figure, giving them a bike that is suitable for those who have either a restricted or a full licence. Triumph, on the other hand, have been forced to take a different approach. As the Street Triple 765 makes over 94bhp and an A2 bike can’t be derived from a machine that makes double the mandated power output, the S version has a smaller 660cc version of the triple, making an A2-legal 46.9bhp. Finally, we have the Royal Enfield Interceptor, which makes 46.3bhp from its air-cooled parallel twin. Enfield weren’t chasing outright power figures in their popular retro, so the fact it is A2-legal is a bonus rather than a specific design criterion. So we have a strangled bike, a bike designed to specifically meet A2 law and a retro that isn’t bothered about performance. Which is the best option for a rider on a restricted licence?
The Autumn leaves aren’t the only things falling as we start the MCN250 with rain on our visors and the roads sodden. Picking the busier A-road route, we set off towards Boston on the A16. With the traffic travelling at a steady 60mph, all three bikes merrily slot into a commuter role and as there is no requirement to rev their engines we are hard pressed to spot their limited power. However, try an overtake and caution is advised. Pull out on the Honda, drop a few gears, and just where you expect the inline-four to take off it remains static in its acceleration as the revs plateau and its power is curtailed. Shifting down a gear doesn’t help. If you want to find acceleration you