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The Ninja JX .21ci on-road engine has an operating range of 4,000-47,000 RPM.

I don't see why you wouldn't want a bike engine. If you tune an engine to make higher revs, then you end up with an engine that has the characteristics of a bike engine, but a very empty wallet. Just start with a bike engine and save yourself the aggro! I love the fact that >11000rpm is accessible all the time, I can buzz the limiter at will thanks to bulletproof manufacturer reliability and I get a free sequential dog 'box in the sump. If it's not enough power for your liking, fit two or turbocharge the one. There are off-the-shelf kits for both options that have been developed over many years.

What is the highest revving road bike right now?

I ride a 1992 Honda VFR400R, red line is 14500rpm limiter kicks in at 16000

Drysdale V8 anyone? 17k rpm?
Not mass production though...

Is he still making those? I remember reading about his stuff way back, and his site was old back then.

That Drysdale V8 links back well to the requirements of this project. The obvious answer to a high revving engine of about 400bhp is one of the few bike-based V8 engines, like the Hartley V8 or the Powertec V8.

I had a 1992 Honda CBR250RR and the factory red-line was 19,000 rpm.
It had four tiny little cylinders, each with four minuscule valves. When they were used in class racing they'd have slight modifications and would easily run to a bit over 20,000 rpm.

humble sabot wrote:Is he still making those? I remember reading about his stuff way back, and his site was old back then.

Well, in that article i linked, it is written:

...Sure enough, he answered and informed me that yes, he was still working on them - in fact, he is currently working on what he says is the final customer order....
..."Current pricing" has risen to around 100 000 AU$, with up-to-date components and revised fuel injection, and Ian laments that even at that price he isn't making any money on the project. It remains a labour of love.

*edit: article is from year ago

Why are the revs of interest?

You can make any engine spin as fast as you want, all you need is a short stroke to keep piston speeds reasonable.

What I find far more interesting, is comparing the MPS of production engines.

Here's a list I started putting together on PistonHeads a while back

http://www.pistonheads.com/gassing/topi ... mance+Wiki

That really is interesting. What I always find is interesting is the weight of these engines. My engine makes a PI of 862, but it only weighs 69kg. That's 69kg/litre, 2.61bhp/kg or 3.03bhp/kg theoretical maximum. What engine has a better power to weight ratio?

andylaurence wrote:That really is interesting. What I always find is interesting is the weight of these engines. My engine makes a PI of 862, but it only weighs 69kg. That's 69kg/litre, 2.61bhp/kg or 3.03bhp/kg theoretical maximum. What engine has a better power to weight ratio?

This? http://nissannews.com/en-US/nissan/usa/ ... powerplant

True, but I was thinking more of engines that are actually obtainable!

Kozy wrote:Why are the revs of interest?

You can make any engine spin as fast as you want, all you need is a short stroke to keep piston speeds reasonable.

What I find far more interesting, is comparing the MPS of production engines.

Here's a list I started putting together on PistonHeads a while back

http://www.pistonheads.com/gassing/topi ... mance+Wiki

I don't find the MPS that interesting. It's also mostly a mechanical limitation. When increasing the rpm's you also need to be able to burn the fuel as the power stroke duration decreases.

andylaurence wrote:True, but I was thinking more of engines that are actually obtainable!

Can't read minds. Only letters But yes your engine has impressive performance figures. =D>

How is the performance index calculated??