Oval piston Hondas?

[Bender]

This is a query sparked by something I read in another thread.

I'm aware that Honda produced some oval piston bikes, but I never understood what the benefits were supposed to be.

Can someone let me know what bikes had oval pistons, why were they used and what were the downsides.

Cheers

[cs363]

It was the NR series Honda's, mostly race bikes but the program did result in the exotic and rare NR750 road bike.

The main reason for the development was to do with racing regulations at the time, go here for more info: http://en.wikipedia.org/wiki/Honda_NR and http://world.honda.com/history/chall...ine/index.html and many more here: http://www.google.com/search?hl=en&s...q=f&oq=&aqi=g4

[Hans]

There's one sitting in the lobby of Suzuki NZ HQ in Heads rd, Wanganui.

[Bender]

Just spent the last hour or so reading up on these engines. Fascinating (imagine the cost of owning one of those puppies).

Suzuki in Wanganui? Wonder why they have one (the fact that it is an utterly classic machine is not lost on me).

[Hans]

Just spent the last hour or so reading up on these engines. Fascinating (imagine the cost of owning one of those puppies).

Suzuki in Wanganui? Wonder why they have one (the fact that it is an utterly classic machine is not lost on me).

It belongs to a friend of the managament, I believe. They're doing him a favour by storing it very safely, and he lets them display it along with an RG500 and some other stuff.

[pritch]

Thanks guys, an interesting question and a good answer. There was an NR750 at Wanganui on Boxing Day, in the Suzuki NZ display no less.
By coincidence I'm currently reading Kevin Cameron's 1992 article on the NR750. His dissertation is fairly technical so it isn't easy reading.
That Honda article provided a human aspect to the story.


Ooops I see while I've been coming and going there had been developments...

[quickbuck]

It belongs to a friend of the managament, I believe. They're doing him a favour by storing it very safely, and he lets them display it along with an RG500 and some other stuff.

This "Friend" of the management.... wouldn't happen to own a sidecar or two??

Darn, it was on display on Boxing Day? Cr@p I missed so much....

Chappy, next year, you can fix the bike yourself! (Where did that come from you may well ask... But he knows...)

[Hans]

I honestly wouldn't know.

[Blackbird]

Not exactly an important fact, but an interesting one to anal retentives....

the mirrors/mirror housings on the Blackbird came from the NR750. Good to see that there was spinoff, hehe

[Pixie]

The benefit was in F1 (bike) racing.The number of cylinders allowed was a maximum of 4,and to attempt to compete with two strokes,Honda made what was effectively was a V8 but with siamesed pairs of cylinders making it a 4 as far as the rules where concerned.In all other respects the design was a disadvantage -and it was,ultimately, uncompetitive.

[CookMySock]

My understanding is, the oval cylinder head area allowed the use of a larger valve area.

Steve

[BMWST?]

My understanding is, the oval cylinder head area allowed the use of a larger valve area.

Steve

NR = never ready.....i thought only the NR 500 were actually oval pistoned..

[rwh]

The benefit was in F1 (bike) racing.The number of cylinders allowed was a maximum of 4,and to attempt to compete with two strokes,Honda made what was effectively was a V8 but with siamesed pairs of cylinders making it a 4 as far as the rules where concerned.In all other respects the design was a disadvantage -and it was,ultimately, uncompetitive.

Hmm - if it has oval pistons, it doesn't have any cylinders at all ... Unless I'm wrong about the definition of a cylinder ...

Richard

[CookMySock]

NR = never ready.....

Oh, here was me thing NR = Not round.

Steve

[pritch]

Hmm - if it has oval pistons, it doesn't have any cylinders at all ... Unless I'm wrong about the definition of a cylinder ...

Richard

There may need to be a new definition?

According to Kevin Cameron, "Gasoline and air find nothing sacred about round cylinders. They simply are convenient, for they can be bored, rebored, and honed, using basic industrial machines."

He goes on to say the English had done work on square cylinders 25 years prior, and that testing of that idea was ongoing in research labs around the world. (As at 1992.)

"Square cylinders?" That could require new nomenclature.