Mick Doohan’s 1994 Honda NSR500 GP bike

1994 Honda NSR500 GP
Mick Doohan

With Phil Aynsley


I made reference in a recent column (Eddie Lawson’s 1989 NSR500 | With Phil Aynsley – link) to the fact that there are extremely few Honda NSR500 motorcycles outside the factory.

Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer

Undoubtedly the largest number in private hands are Mick Doohan’s five World Championship winning bikes.

Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer
Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer exhausts

I was lucky enough to be able to spend a day photographing a couple of these recently.

Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer front brakes
Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer dash

I started with his first, the 1994 bike. It continued to use the “big bang” firing order motor that had been introduced in 1992.

Honda NSR Doohan ImagePA
The 1994 NSR500 retained the big-bang firing order
Honda NSR Doohan ImagePA
The big-bang engine was found to help traction, torque and acceleration

This had all four cylinders firing within about 70 degrees of each other. Torque, traction and acceleration had all been markedly improved with this design, as was the overall ease of use.

Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer
Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer

A heavier balance shaft (originally introduced when the cylinder angle had been increased from 90 to 112 degrees back in 1987) also helped ridability.

Honda NSR Doohan ImagePA
Fuel injected was tested on Shinichi Itoh’s bike but did not offer enough gains to be adopted
Honda NSR Doohan ImagePA
A water-injection system to cool the exhausts was also tested

As an aside during 1993 Honda experimented with electronic fuel injection on Shinichi Itoh’s bikes but it was deemed not enough of an advance over the standard carburettors to warrant continuing with.

Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer
Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer

One interesting feature that was introduced during 1994 was water-injection into the exhausts.

Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer
Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer

The cooling effect and resultant lowering of the gas speed gave an increase of 10 hp in the 6000 to 10,000 rpm range.

Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer
Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer

Mick chose to use the normal motor however as the carburation was compromised by the injection.

Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer
Honda NSR Doohan ImagePA
Mick Doohan 1994 NSR500 racer

Source: MCNews.com.au

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