NR 500

[ou812]

Don't know how many of you remember Honda's first attempt at running a 4 stroke against the 2 strokes in 500 GP racing. This was there oval piston 4 stroke 500. I posted this because this is the first time I have ever seen a picture of the tach, check it out 20 grand redline. While the bike was way ahead of it's time for a bike some 28 years ago, it only ran twice and was retired. Honda history is a long one of development of 4 strokes to get rid of 2 strokes.




http://www.imai-racing.com/imairacing64.htm

[Mad Dog]

That engine was quite an engineering work of art.
I couldn't find good info on the net about this engine so I'll comment from my fuzzy memory.
AS OU12 said, Honda was a predominant 4 stroke company.
In the 60's they had their straight 6's that revved 15k +.
I had met a Honda insider as a young man and he explained that Honda'a philosphy was to rev em high for power.


Honda wanted to build a V8 to race against the 2 strokes in the 80's.
Rules permited only 4 cylinders, so they siamesed the cylinders together in the infamous oval, now it's a 4.
IIRC they had 8 valves per cylinder / oval.

The continuing problem was ring seal and ring breakage. Easy to believe.
They gave up and retired it. One of Honda's comment was they learned alot about thermal dynamics, ring sealing etc.

[ou812]

Yep it was retired but did to some degree return as a very exotic very limited street bike as the NR750, one of the coolest street bikes ever built

[jbird_710]

I used to subscribe to Cycle World and they had some extensive articles about the NR. I remember a lot of people called it the "Not Ready" 500 due to the enginneering problems.