Topic: Went to my local Honda dealer to order some parts and look what I saw for sale..

[Raul CB750K1]

Have you ever seen one? They are harder to find than hen's teeth.

[dusterdude]

what it is? and do you always carry your camera with you?

[SteveD CB500F]

NR500?

[Raul CB750K1]

Honda NR750. A great piece of engineering but a big sales flop. Oval pistons, V4, double crank per piston. It's yours for 120.000 euro!!!!!!!

Actually I normally don't carry my camera with me, but went the other day to the shop, saw the bike, chat with the salesman and asked wether he minded if I return with my camera. He told me "whenever you want, I don't think it will sell quickly....". I passed by today and took the pictures. They bought it in the 90's, but as it didn't sell they hibernated it. Now it's on display but with no price tag, with a big sign saying "please don't touch the bike". It's like the Imperial Palace auto museum, pieces of art for sale to anybody with the dough...


Raul

[Bob Wessner]

Oval pistons

Seriously   Is there an engineering/performance purpose  

After thinking about this some more, I guess it would be a way to increase valve size without necessarily increasing cylinder volume??

[Raul CB750K1]

I don't think there was any other purpose than to stand out of the rest regarding high-tech engineering. The best proof that it didn't bring any improvement is that it was discontinued.

Something like the Dodge Tomahawk. It's just a way of showing self-complacency and high engineering, but nothing more. The NR750 is a motorcycle destined to rest in a museum. Anybody with the dough to buy it will rather buy a MV Agusta F4 Serie Oro, that's even more exclusive and less expensive. If I had the money I would rather buy the best street race bike of the big four (Yamaha R1, Honda CBR900, Kawa ZX9R and Suzuki GSX1000R) and still will have money remaining to give the people at VB so they can hire models with bigger boobs!! HAHAHAHAHAHA


Raul

[jsaab2748]

Oval shaped pistons/cyls allowed for more valve area, hence better breathing charachteristics and larger valves without exceeding engine size restrictions for racing. Thought I heard that somewhere. Originally designed into the NR 500 race bike and inteded to give it the extra horsepower required to compete against two strokes of the era. Late 70's early 80's maybe? Didn't Freddie Spencer ride a 500NR? Someone correct this if incorrect.

[Bob Wessner]

I'd hate to have to try fitting rings to oval shaped pistons. 

[ofreen]

Oval pistons

Seriously   Is there an engineering/performance purpose  

After thinking about this some more, I guess it would be a way to increase valve size without necessarily increasing cylinder volume??

The object was to attain V8-like performance in a rule-meeting 4 cylinder engine. 

Greg
'75 CB750F

[Raul CB750K1]

That makes sense....

[6pkrunner]

I remember seeing them new at the dealer and wondering about ring life. But an engineering masterpiece for skirting the rulebooks.

[Bob Wessner]

Wow, even more extreme than I had envisioned. So, are there two of these per engine, or one 

[Raul CB750K1]

If I'm not wrong, four of these...   

Raul

[SteveD CB500F]

Yes it was Hondas attempt in the 70's to fight off the GP 2-strokes (500cc square fours) with a 4-stroke.  So four cylinders was the limit.  It didn't work so Honda invented a 2-stroke racer instead.

[Buffo]

did that thing have 2 spark plugs per cylinder?

[Einyodeler]

I guess it was never designed to be rebuilt. Imagine trying to hone those cylinders

[MRieck]

All those bikes were sold almost immediately as they were was a very limited production run. Titanium coated windscreen etc. Honda built them tp prove it could be done after that racing flop called the NR500. Very proud and stubborn those folks at Honda. Mick Grant crashed one in 1979 I believe and watched it burn to the ground. Must have been a $250,000.00 fire with R&D etc. The 1984 NSR500 was another Honda racing flop with the gas tank located under the engine.

[Sam Green Racing]

I think the asking price new in the UK was £37,000,  WOW,