Such an ordinary looking box....

[Kopfjäger]

Honda NR750 sound

[DucHead]

Cool thread!!

What was the redline on the 750? 

What made them maintenance intensive?  Nevermind, I just counted the valves on the 500 motor!!             

[MotoCreations]

GP rules at the time (late 70's) didn't allow more than 4 cylinders, and all the bikes were 2-strokes.
Honda wanted to re-enter GP racing with a 4-stroke, but needed a V-8 to hope to be competitive with the 2-strokes.
IIRC, fundamentally all for naught; too heavy, thirsty, and maintenance intensive.
Honda caved and built 2-strokes.

Plus almost every racing santioning body in the world added a few additions to the rules book -- ie: pistons must be round in shape.  Reason being that Honda held almost all the patents for these pistons and getting the compression / oil rings to work! (which was the most difficult part of the equation) 

Too bad unfortunately -- the NR750 I rode had the most incredible powerband of any motorcycle that I've ever ridden. 

[Speeddog]

Here's a pretty good road test, combined with a 'sedici:

http://www.visordown.com/road-tests/bloodlust---honda-nr750-vs-ducati-desmosedici/7049.html

[DucHead]

Here's a pretty good road test, combined with a 'sedici:

http://www.visordown.com/road-tests/bloodlust---honda-nr750-vs-ducati-desmosedici/7049.html

"The first NR, the NR500 0X, combined an oval-pistoned engine with a monocoque frame. By the end of its development it was reckoned that the NR produced around 130bhp and revved to over 20,000rpm, but despite all their best efforts Honda couldn't make it competitive."

[Rob Hilding]

snip
Based on the cost of the bike..what's a piston like that cost?

I think based on the picture - about 10 bucks 

Cool pic(s) Thanks!

[Speeddog]

If you have to ask, you can't afford it. 

I've no idea what $ the piston traded hands for.

[EvilSteve]

A friend of mine has one actually, very cool bike, I probably wouldn't ride it even if he did offer.

[junior varsity]

man. talk about needing crazy tight tolerances when running multiple con-rods per piston. hope the metal doesn't expand and contract at different rates or in different places on the rods to the same piston.

[KRJ]

I was going to Honda Tech school at the time they were developing the oval piston concept, the theory and R&D behind it was discussed at length, when a corporation like Honda launches a project like that they have no limit to engineering,only the best were employed to the cause. Honda really thought their idea would revolutionize the internal combustion engine, and spent a lot of coin trying,They had not figured out how to seal the rings on the piston flat sides yet, and also production machines for the boring / honing process. It was a very exciting time though, and as young students it was huge, too bad it didn't work out, but it opened a lot of minds and brought a lot of knowledge to light.