Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/127812
suspension were perfect, allowing me to keep up corner speed in Assen's fast turns without chattering the front wheeland that's really the secret to Superrnono supremacy: having a torquey motor that delivers good acceleration, then a goodhandling cha is that allows you to keep up hard-earned momentum. The MuZ scores heavily on both fronts. It steers beautifully, with a stable, balanced feel that's probably a function of the revised steering geometry and weight distribution as much as the suspension settings - you don't feel the front end might tuck in as you lay into the·tum on the brakes, which was my only criticism of the Tigcraft-built RS2, even with Edwards' stiffer suspension settings which meant his bike definitely didn't ride bumps as well as Richter's does. Yet Riga's bike doesn't have excessive weight tran fer hard on the brakes into the Assen chicane, in spite of the more compliant suspension. You can turn in late without the back wheel feeling unloaded, and the twin 280mm Brembo brakes - same as on my Ducati - give (Above) The 686cc single-cyllnder engine sits in a tubular twin-spar chassis. Fairly simple In design, the MuZ weighs in under 280 pounds and produces n horsepower. (Left) The author turned in his Ducati for a day on Rigo Richter's MuZ, and he came away impressed. great stopping power with lots of bite, even if without desmo valve gear you can't use quite as much engine braking. At 279 pounds (half-dry) the MuZ weighs the same as the Ducati, but where it scores heavily over the Italian bike is out of slower turns, thanks to the extra punch from a 686cc engine 20 percent bigger in capacity, that also delivers 10 percent more power at the top end - 74 bhp at the rear wheel at 8,200 rpm on a Dynojet, translating to 77 bhp in the real world out on the track, where the dynamic effects of the sealed airbox can play their full part. Of course, I've had a grandstand view all season of how well the MuZ accelerates, and how effectively it puts the extra power to the ground: the vital 15 to 20 feet jump Elli and the boys get out of turns is very hard to peg back once you're straightened up and flying right. Experiencing this for yourself confirms the definite advantage the extra punch delivers: The Peter Liebing-developed, Slipstream-built engine is surely the best Yamaha Supermono motor I've yet sampled, with perfectly set-up carburetion on the twin 39mm FCR Keihin flatslides that allows you to pull cleanly out of a slow tum as low as 4,000 rpm, coming on strong at 6,000 rpm to deliver real- ly meaty acceleration up to the 8,200 rpm power peak - and beyond. It holds the power all the way to the 8,900 rpm rev limiter, though in general MuZ doesn't rev the engine as high as other Yarnaha users - another reason the bikes are so reliable. Changing up at 8,500 rpm via that perfectly adjusted MF power-shifter gives a relatively narrow but still very usable powerband, which the closed-up ratios of the RC Sugo five-speed gear clUster allow you to profit from. And the engine is smooth, too: I've ridden other XTZ five-valve Yamaha race motors which vibrated badly as soon as you revved them and they started to deliver competitive power, but not this one. It's not quite as smooth as the Ducati at high revs, with some tingles through the pegs and bars, but it's a tribute to all concerned that it's as potent as it is, yet a rider-friendly - partly thanks to the way Tigcraft mounts the engines in the frames, partly to the way the engine's been developed and built. Peter Liebing and Martin Sweet work closely together at a 600-mile distance, with the MuZ race engineer passing the fruits of his R&D carried out in the Zschopau factory to the London-based tuner, to incorpora te in each of the six .(Below) The RS3 uses a 41 mm White Power front fork and 280mm Brembo discs up front.• race engines he builds and maintains for the German team. Slipstream customers benefit too, but six months down the line, says Sweet, whose agreement with MuZ allows for a half-season trickle-down delay - still, that means you can have your Rigo Replica XTZ motor ready for the start of next season if you order it now! Though they've tried various capacities in the past, up to and including a very unreliable 736cc Italian-sourced jumbo-motor two years ago, MuZ has now traded power for reliability, using a 102 x 84mm configuration with a bore 2mm over standard, thanks to a threering Omega piston that delivers 11.5:1 compression with Liebing's completely reshaped combustion chamber, matched to a Carrillo rod, stock unlightened crankshaft and crankcases which haven't been strengthened, stock clutch and valves, both with stiffer springs, and a ported, flowed cylinder head fitted with a Megacycle X4 camshaft. The result is a powerful engine that is