Archive post from Junior Torque editor Richard, from 2012.
It’s over a decade now since the Rotax Max was introduced into the world of Karting, slowly but surely beginning the destruction of 100cc racing. Rotax now commands the lions share of almost every single kart paddock in the country, with MiniMax, Jnr Max and Snr Max also convincingly the biggest grids at both Super 1 and FKS.
Whilst the majority of the karting world agree that the Rotax is an adequate solution to the issues that faced 100cc karting, with an unrivalled blend of both longevity and performance, it still feels like a hobby engine that lucked into the Karting market at the right place and the right time.
So when we turned up to a soggy and cold Rye House earlier this month, we were expecting to find yet another engine that has tried and failed to match the ‘adequacy’ of the Rotax Max. Whilst some engines such as the Biland, the Leopard / Lynx and the PRD Fireball have matched the Rotax in certain areas, they have all been let down by being less competent in other areas.
First impressions of the Aixro XR50 are somewhat uninspiring, with a black plastic engine cover masking the bulk of the engine and the sheer size of the small little Rotary motor making it look slightly toyish. Front disc brakes, a chunky chain and a radiator on the correct side are the only nice additions when compared to the looks of a normal Rotax engine. Even so it’s hard to believe as you stare at the little motor that underneath it’s black engine cover beats the heart of a 50bhp kart engine. That’s right…. I said 50 BHP!
This specific XR50 had been fitted with an onboard starter, thus eliminating the need for a JICA style external starter. As the engine was fired into life, the smooth growl of the 4 stroke engine did little to suggest to us that this engine had ICC beating potential, but having been assured pre test day that this thing would destroy almost any other kart, we cautiously stepped in for our first session.
Now I’m a 100cc man through and through, having driven for the majority of my life in 20,000rpm screaming machines. Having completed one lap out on an extremely soggy Rye House circuit, I was already fully converted to the world of the Rotary. This thing is BRUTAL, with the most linear and torquey power curve I have ever experienced in a kart. Every millimetre of throttle gives an instant and mind blowing surge of power; power that is unlike any other kart engine I have ever experienced. There is no lag, no fuss and the power just never tails off. The engine packs a punch that would floor Ricky Hatton, but with absolutely no effort, no vibration and with an ease that gives the impression this thing is hardly even breaking a sweat.
The closing speeds with other karts out on track were just ridiculous, and as the weather dried the kart just became better and better. The Rotax has never been a slow engine, my main beef with it has always been its lack of driveability. We expected the Aixro to be equally as undriveable in the wet conditions, but the engine has an incredible ease of use that even in the slippery conditions and almost slick rear tyres, it was as easy to drive as a corporate kart…. a corporate kart on steroids. We also expected the kart to become less dramatic as the track dried, but we were once again comprehensively blown away more and more as the sun burned away the standing water from the track. The brakes became astounding, the power now even more astonishing now that we had traction and the Bridgestone YGB’s we were running on reminded us of just how physical and punishing driving a kart can be.
In the damp conditions the kart was already lapping quicker than the Rotax’s at the club meeting the day before, and we have no doubt that given some proper dry weather it would be several seconds a lap quicker than the inferior Rotax.
Just as we started to think the news couldn’t get much better we discovered this rapid engine also has service intervals of over 50 hrs, with low emissions, bullet proof reliability and also an unbeatable power to weight ratio. The good news just doesn’t stop, in fact we had to seriously think before we could think of something we DIDN’T like about the engine. Even then it seemed unfair to comment on the fact that the engine doesn’t sound like a good old 2 stroke engine, as noise pales into insignificance once you drive the Aixro!
The Aixro really is the only engine that could realistically usurp the Rotax as the engine to use in UK Karting, and we would back it all the way to the top. If you haven’t tried one then we suggest you book a test day now, we promise you won’t regret it. This engine has redefined karting in our minds, and we have absolutely no doubt it will do the same to anyone else that drives one.
If you are interested in the Aixro race series, please check out the website here.
We wish to thank Richard from AIM Motorsport for providing the kart, and SmartyCam for providing top quality onboard cameras.
Author: Clerk of the Course
The Clerk of Junior Torque. Administrator, Editor and Dictator!