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/challenge/1979pistonengine/index.html and many more here: http://www.google.com/search?hl=en&safe=off&rls=com.microsoft%3Aen-nz%3AIE-SearchBox&rlz=1I7ADBS&q=honda+oval+piston&aq=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:innocent:....

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. :rolleyes:

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.

[Ocean1]

Made six valves per head and twin sparx easy.

Hideously expensive to manufacture...

[boman]

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...)

And here is a picture of the bike at Wanganui. Very nice to see one in the flesh, so to speak.:clap::drool::2thumbsup

[HenryDorsetCase]

Made six valves per head and twin sparx easy.

Hideously expensive to manufacture...16 valve per head unless I'm mistaken: each oval piston had eight valves. And two plugs.

there is a decent write up on it in "V-Force" by Julian Ryder.

[nadroj]

The above mentioned bikes at Suzuki HQ Wanganui on Boxing day.

[boman]

And an interesting internal view of the Engine

[nudemetalz]

.and if you let some stupid "person" who obviosuly can't ride, on an NR750...this is what happens !!
http://www.youtube.com/watch?v=6wm0yWZ0SGo

[White trash]

Much as I hate to say it, probably one of the best looking road bikes built, along with the RC30.

Shame it's a Honda and therefore gay as. But don't tell Steve I said that about his bike............

[HenryDorsetCase]

http://www.youtube.com/watch?v=UNFmCnlXhPk&NR=1

sounds amazing.

[Pixie]

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.

The Pivotal Engine from Christchurch has curved square bores

[HenryDorsetCase]

I've been doing that wet weekend thing of looking at old motorbike magazines. Found this last weekend.

hopefully it loads: our fancy copier thing at work does colour now. mmmmm colour.

From the June 1992 Cycle World, Alan Cathcart's test of the NR750.

[HenryDorsetCase]

Grrrrrr. too big to upload each page is 4MB plus grrrrrr.

[merv]

Yeah was all about building within the rules of the day and trying to make a more competitive four stroke engine for racing. I am sure the rules would now outlaw anything but cylindrical "cylinders" closing that loop hole. The road going NR was a great looking bike and the VFR I have took some of its design cues from that so I'm not complaining. The $100k price tag for an NR versus around $18,500 when my VFR came along meant I didn't have a problem with not having even thought of buying an NR.

In the end the 2 strokes have been killed from MotoGP anyway, so no need for such variations from the norm and besides the MotoGP rules are quite restrictive on design these days.

[Farab]

Unboxing a NR750 & RC30 20 years later!

http://hellforleathermagazine.com/2010/03/unboxing-a-honda-nr750-and-rc3.html


A video of the unboxing:

http://www.youtube.com/watch?v=YvmnSiVpoH8

[Woodman]

So what happened to the v8??

[sil3nt]

Unboxing a NR750 & RC30 20 years later!

http://hellforleathermagazine.com/20...0-and-rc3.html


A video of the unboxing:

http://www.youtube.com/watch?v=YvmnS...layer_embeddedYou can't copy links from another page by highlighting the text you need to copy them from the browsers address bar! Or right click on the link from another site and select copy link address.

[rwh]

Unboxing a NR750 & RC30 20 years later!

http://hellforleathermagazine.com/20...0-and-rc3.html


Fixed link:

http://hellforleathermagazine.com/2010/03/unboxing-a-honda-nr750-and-rc3.html

I guess you follow on from there for the vid.

Richard

[Farab]

You can't copy links from another page by highlighting the text you need to copy them from the browsers address bar! Or right click on the link from another site and select copy link address.

Apologies, fixed!