http://sohc4.net/index.php?title=Image:Hcm23.jpg
WOW.... a 748cc four cyl, with 8valves per cylinder???
Oval pistons? http://sohc4.net/index.php?title=Image:Hcm20.jpg
Some nice racers too
l8r
The legendary NR750
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Born from a slight misinterpretation of the GP rules of the day
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The rules stated as well as the 500cc 2 stroke machines then prevalent, competitors could use a 750cc 4 cylinder 4 stroke engined bike.
Honda read this, and set about building what turned out to be an awesomely powerful 750cc V8 with 4 valves per cylinder
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It was only when they got to the stage where that need to homologate the engine for racing that some one checked the rules, and noticed the bit that read
4 Cylinders 
So after a hasty redesign, with some extreme out of the box thinking, they ended up with the world's first (and to date only) dual con-rod, oval pistoned racing engine.
I once saw an NR750 being used in anger at an Oulton Park track day. It sound pretty close to awesome in twin plug, 4 cylinder guise
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One can only imagine what they sounded like in their original format
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