YAMAHA YZR500 REPLICA
A Down Under homage to Norick Abe
Aussie Mick Costin, owner of Costin Motorcycle Engineering, is a two-stroke maniac. In fact, I’d go as far as to call him the mad professor of two-strokes Down Under. Thankfully for die-hard GP fans like me, he specialises in replicating the glory days of the mighty, raw, untamed and awe-inspiring 500cc two-strokes. He is currently contracted to build the replicas for the World GP Bike Legends series. In his humble workshop in western Sydney, Mick makes these dream bikes for lucky cashed-up customers from all over the world. This beauty was shipped off to Japan just a few days after we got the opportunity to photograph and ride it at The Farm. Mick had also just finished a Mick Doohan replica NSR500 and a Wayne Rainey replica YZR500. “I think 500cc grand prix bikes are the most fantastic motorcycles ever built,” grins Costin, with a little crazy glint in his eye. “Norick was a gutsy, brave rider and the 1997 YZRS were the best looking, particularly in these colours.” Time to talk about the build, so let’s look at the engine first. It started life as a standard RD (RZ down here) 500LC V4 engine. The engine was completely stripped and re-built. The crankshafts were replaced by an RZ Performance item with new bearings installed in the standard cases throughout. RZ Performance con-rods hold Mitaka pistons and rings. The cylinders were ported by Mick and the heads re-shaped to GP spec. The standard gearbox was re-built and Mick converted the clutch to a dry set up using a Tz350-based clutch hub, basket, pressure plate and clutch plates. A new longer custom gearbox input shaft was fitted and the original RD500 outer cover modified and fitted.
“Jeff on the Abe Rep YZR. The YZR500 replica is just like the real thing into turns. It is built off a real jig and has the same geometry as the original bike.”
The 28mm Mikuni flat-slides have CME wire covers and the oil pump is removed so 35:1 Castrol A747 is used. A CMA GP plug-in race ignition system is fitted with a programmable ignition curve and powervalve controller. All electrical components are located at the front of the bike for easy access. The sharp end of any stroker are the expansion chambers and these are CME titanium handmade pipes, along with genuine Yamaha YZR500 mufflers/ end-cans. Keeping things cool is a custom CME radiator, with a standard RD500 water pump and TZ Yamaha tanks. Engine aside, what about the home it’s been put in? It has to look right, right? The frame is handmade by Mick using his own original ex-factory YZR500 frame jig using 6061 T6 aluminium, which is heat treated after welding. “I use sheet, billet and extrusions,” said Mick. “Unlike many massproduced frames, we heat treat ours back to T6 condition after welding. This gives the aluminium back its maximum strength and makes it a very stiff structure. The frame has exactly the same dimensions of the original Yamaha YZR500 frame. Seat height and swingarm pivot point are also identical. The frame and swingarm (from a Yamaha R6) are painted black.” Custom-made triple clamps with a magnesium top nut hold 43mm Ohlins forks. Out the back, custom linkages join the Ohlins shock, sourced from a TZ250. The forks were anodised black and completely re-valved and sprung to suit the bike, as was the shock. Brembo calipers bite Brembo rotors on Brembo wheels, with Bridgestone racing slicks fitted. CME (Costin Motorcycle Engineering) braided brake lines are fitted both ends, and both the front and rear uses a Brembo master cylinder. Topping off the high-end parts list are Brembo brake pads. The handlebars are CME YZR500 replica items, as are the foot pegs. Instruments include a Stack tacho and TZ temperature gauge. Once the engine went in, all this beauty needed was to be wrapped in that stunning bodywork. While the YZR500 fairings were being painted, Mick got to work building a fuel tank. He got hold of a late model TZ250 fuel tank and widened and re-shaped it to suit, and he did a fantastic job. The front and rear guards are genuine items and the seat, well, that came from Loris Capirossi’s bike from the 1996 season. Once the bodywork was done and the tank painted, Mick put the bike together and added the finishing touches. This stunning 500 was the result. Honestly, it’d fool anyone!