MotoMatters.com is delighted to feature the work of iconic MotoGP writer Mat Oxley. Oxley is a former racer, TT winner and highly respected author of biographies of world champions Mick Doohan and Valentino Rossi, and currently writes for Motor Sport Magazine, where he is MotoGP correspondent. We are featuring sections from Oxley's blogs, which are posted in full on the Motor Sport Magazine website.
Bigger bangs for bigger bucks
This season Marc Marquez will use a new engine configuration, inspired by Honda’s first big-bang GP bike of the early 1990s
Many moons ago I used to buy a plane ticket to Tokyo every November and then a bullet-train ticket to Suzuka, where HRC would let a few of us ride its GP bikes around Soichiro Honda’s magnificent figure-of-eight circuit.
On the very first lap of my first visit in 1989, Eddie Lawson’s title-winning Rothmans Honda NSR500 flew into a blood-curdling tank-slapper down the back straight, flat-out in sixth gear. I pulled into the pits, where an HRC mechanic fussed around the front of the bike, then grinned widely as he turned the steering damper up to maximum and sent me on my way. No more tank-slappers but now the NSR turned like an oil-tanker. And Lawson won the world title on this bike. Some achievement.
I returned in 1990 and 1991 to enjoy slightly less terrifying outings on the next two NSR500s.
In 1992, everything changed. The NSR was no longer the scariest rollercoaster ride of your life; instead it was like the sweetest road bike you’d ever ridden, with 160 horsepower and 130 kilos.
And all this from re-timing the crankshaft. In 1989 Lawson’s NSR ran a 90-degree crankshaft, firing one cylinder every 90 degrees. In 1990 and 1991 the NSR used a 180-degree crank, firing two cylinders every 180 degrees. In 1992 all four cylinders fired within 70 degrees.
Changing the combustion timing didn’t merely change power delivery, it transformed the way the motorcycle handled, steered and everything else.
Read the rest of Mat Oxley's blog on the Motor Sport Magazine website.