Has it really been thirteen years since the R1 first appeared? It was late summer, 1997, when we saw the first pictures of Yamaha's game changer. Back then, Honda's CBR900RR ruled the roost-nothing could come near its awesome combination of light weight and strong power output. Kawasaki had tried with its ZX-9R, and Yamaha had come up with the FZR1000R, but both of these were bloated heavyweight bruisers in comparison to the CBR.
So Yamaha did the obvious thing and built a bike that blew the Honda out of the water. A genuine 150 HP superbike in a tiny, sub-600cc chassis package, with "No Compromise" as its catchphrase. It instantly became a legend, and although some of the later versions have ended up a little flabby, it's earned a place in the SSB Hall of Fame. Here's the inside story on the tech and design behind this incredibly influential motorcycle.
Kunihiko Miwa, designer of...
Kunihiko Miwa, designer of the original R1, explained that it was created with "no compromise" at its heart.
The original R1 was a triumph of packaging. Putting a 150 HP engine into a chassis smaller than most 600s was groundbreaking stuff, but how did Yamaha do it? The motor was made more compact by moving the gearbox up and behind the cylinders. Previously, engine designers simply laid the crankshaft, gearbox input shaft and output shaft all in a line, making the engine long front-to-back. Yamaha relocated the gearbox shafts into a triangular arrangement, moving the crank and output shafts closer together. This made the engine shorter and allowed for a longer swingarm while retaining the desired short wheelbase. A longer swingarm improved stability, as did the R1's long-travel front forks. These gave more "sag" in the front suspension, keeping the front wheel on the road longer during hard acceleration.
Fueling on the first R1 was by 40mm Mikuni carbs, so the power delivery was super-smooth (especially compared with some of the fledgling fuel injection systems of the time), and Yamaha's EXUP valve further improved midrange. Although almost every bike has an ECU-controlled valve in the exhaust system now, back in 1998 it was still a novelty thanks to the firm's patents on the technology.
By 2002, fuel injection was becoming unavoidable due to emissions regs. The then-available systems needed careful design to provide good fueling, but Yamaha decided against using the same dual-valve throttle system used on Suzuki's GSX-R range. Suzuki's system used a computer-controlled secondary butterfly valve to match the actual airflow into the engine to what the engine can actually cope with. So when the rider slams the throttle open at low revs, the GSX-R opens the secondary valve more slowly, which prevents the airflow into the engine from "stalling."
Instead, Yamaha pioneered a novel CV-carb-type system. This used a suction piston similar to those on a CV (constant velocity) carburetor to control a throttle slide. When the rider opens the throttle the butterfly valve opens instantly, but the spring-loaded suction piston is opened more gradually by the engine's intake vacuum. As it opens, the airflow is more smoothly managed.