Rieju say this new Yamaha-powered 125 is the ultimate Supermoto 125, and have even given it the code name 'Duke Killer', referring to KTM's new 125 Duke.
In terms of performance, Rieju have a point. The SM is a riot to ride and exceeds the KTM in almost every performance category. But it's considerably less refined than the 125 Duke, and much harder to ride - it would be a real challenge for novices.
The bike is based on the MTR 125 Pro and has a host of bolt-on accessories to boost handling, looks and performance - think of it as a R version. It has adjustable suspension front and back, with 40mm Marzocchi front forks, and a trick looking shock at the rear.
There's also a Leo Vince alloy race silencer and the Yamaha WR125 engine has been given a Pistal race piston, twin radiators and Keihin CVEK 30mm carbs rather than fuel injection.
There's also a quick-action throttle, race filter and switchable CDI mapping which raises the rev limit to 12,000rpm.
Limited edition black with gold seat trim, alloy sump guard, fork and handlebars give it that sporty Supermoto race appeal. Our test bike was pre-production model, and was missing indicators, mirror and even an ignition key.
However, overlooking the missing parts, the Rieju still didn't feel complete. It didn't have the level of finish of KTM's Duke or sporty Japanese models like Yamaha's YZF125R.
The clocks are very basic and the bike has a lightweight, kit feel but arguably that's the idea - it's a mini race bike and weighs just over 100kg. But, more seriously, the tuned Yamaha four-stroke never fires on the first dab of the starter button. Once it does, it really barks into life through the free-flowing Leo Vince exhaust and sounds great for a 125, and the tuned motor revs freely on tick-over - it feels like a quick-revving motocross bike. The noise alone will get teenagers salivating. And once you start thrashing the road legal 125, most potential customers will put the minor gripes to the back of their minds. The booming exhaust adds to the sense of speed, it loves to rev and will hold 70mph even if you're sitting bolt upright. Tuck down, flick the engine mapping into race mode and there's more to come.
Suspension is fully adjustable and is easy to adjust. Combine Supermoto handling with a rev happy little 125 motor, and it rekindles memories of old two-strokes. I can't remember a four-stroke 125 being this much fun. The turning circle is stupidly small, and you can flick it around like a heavy mountain bike.
I love this little Rieju. It's light, flickable, sounds great, looks trick and reminds me of the fun two-stroke days.
But it doesn't feel solid. How long will the tuned engine last? The gearbox feels terrible, build quality is low and it seems designed for experienced 125 riders - is there such a thing? If you want a practical all-round 125 look elsewhere. But if you want the most hardcore supermoto 125 ever, then look no further.