Wouldn't a rotary engine motorcycle be a more powerful machine? The Mazda RX8 uses a rotary engine that is only 1300cc, or 1.3L engine, and produces around 220 break horsepower. If that is so, wouldn't a 500cc rotary engine produce far more power than a current 4-stroke engine? if this is so, what are the complications that would keep an engine like this from being implemented in a motorcycle?

I have always loved that design as well. i think it could be done quite well.

Suzuki made a street version a long time ago...

http://www.suzukicyc...E5-Rotary.shtml

Cooling and lubrication were the big issues with rotaries. They use an injectorlube system to lubricate the roter tips a bit like a two stroke.

As a result of using ports to allow fuel in and exhaust out of the motor, and there is no cooling for the exhaust, the exhaust headers get really, really hot.

And also, the emission control gear to keep them clean enough to run in the USA is rather large and heavy. They have exhaust emissions like a two stroke to clean up.

If those little issues could be solved, we'd have a winner.

http://thekneeslider...or-motorcycles/

And for sure check out this link...

specs/' class='bbc_url' title='External link' rel='nofollow external'>http://www.race-spor...0-wankel-specs/

Ride said:

That Kart engine is a prime example! Imagine if a giant company like BMW put their R&D division on designing a rotary engine motorcycle, it would be an amazing piece of machinery! And BMW motorcycles always seem to have technological advances that give them advantages over other motorcycles, a rotary engine would be a perfect fit the for the company, and that could transfer over to Husqvarna. Give Husky something to truly set them apart from the big 4 and KTM!

There've been a few wankel powered motorcycles. The afforementioned Suzuki RE5 was probably the most successful. I've seen a couple in person. The radiator is HUGE (about what you'd see in a Honda Civic) as is the super complicated carb (which had five control cables IIRC).

Saachs made several small wankel powered street bikes, and a couple dirt-ish (similar in size and performance to an XL185) bikes in the '70s. I have a Dirt Bike magazine from the early '80s stashed away which briefly mentions some europeans racing a wankel powered MX bike.

Saachs also made wankel powered lawn mowers and a few wankel chain saws...

Norton made some rotary roadbikes and wonderful racebikes in the 80's and 90's, culminating in winning the '92 TT. Check out the racebike history at http://www.nortonmot...ry%20Racing.htm

Norton rotaries in sight and sound :
wow, listen to that. Who cares about a little smoke?

Some more rotaries from different manufacturers at http://www.motocyclo...otorcycles.html

Edit: Silly me, I completely neglected to mention that Norton rotaries are still alive and kicking (although given Norton's history one wonders how long for...)



http://www.nortonracing.com/

The Wankle engine was, and is, a dinosaur. It never stood a chance. No matter how hard they try, engineers can't get an efficent burn from a rotary disc. Novel concept. Dismal results.

Krieg said:

the RX8 is a wonderfull engine. Many RX7 motors in plains.

I forgot about the Norton one. They still make police bikes with that motor in it because it runs forever and needs little maintenance. Stories of 500K + miles on a lot of them.



http://www.nortonrotary.org.uk/

Krieg said:

I really feel that if we put the power and expertise of today's engineers to work, we could have a more efficient machine than in the past.

The combustion chamber isn't a great shape (it gets kind of skinny as the compression goes up), but they could be made to run reasonably clean with direct fuel injection I guess.

Anyway, hang the efficiency, just put a bigger fuel tank on! Rotaries make great race engines (just like 2-strokes). Everything that's fun gets banned in the end. ;)

I too have always loved the elegance of this motor design. A piston has to come to a dead stop every stroke. Many years of refinement went into proving piston design to be worthwhile. But then they did not really have other options, and much design had already occured with steam engines. I'm happy that mazda has stuck it out all these years. If norton keeps the fire burning it might be passed to dirt bikes. It might have a cool effect on handling and stability, as well as running with less vibration.

The RE5 was "cool", but it was also a slow, heavy tank. The header pipe had cooling fins on it because it ran so hot. I've rode one and was excited before the ride, yawning after it.

Good designs have a way of taking over due to their own inherent superior properties (don't wanna hear any 2t vs 4t comments!) or benefits. The rotary never took hold, draw your own conclusions.

I do love the rotary design, but I'm pretty sure it would be nearly impossible to make one compact enough to satisfy todays dirt-bike demands. Noone wants an overweight powerplant that relies on revs to do a job.

engine life especially the rotor were too short c/w reular combustion engines. The fuel economy was atrocious. As stated they were a polluter and were very hot running.

F-that rotary design, this is the technology I want to see Husqvarna use:

http://www.ski-doo.c...ch/en/Index.htm

HuskyRips said:

direct injected 2 strokes? Yep, we all want that.

Ride said:

What's keeping it from happening?

the big vertical twin , 962, is in production and the rotary will follow next. looks like we will have a socal dealer, perhaps next year.

http://www.motocross...B9044BB6C7A2BC5

WEIRD STUFF! COATES SPHERICAL ROTARY VALVE ENGINE:
THERE ARE NO VALVES, JUST A SERIES OF SPHERES ON A ROD: SORT OF A SHISH-KABOB



Unlike a conventional piston engine that ignites the fuel and air mixture in the combustion cycle and evacuates the gas byproducts in the exhaust cycle via the rotation of the camshaft and spring-loaded poppet valves (with springs, valve guides, buckets, rockers, shafts and the valves), the Coates Spherical Rotary Valve Engine is made up of spheres rotating on a shaft sandwiched between a split head. These spheres are either chain or belt driven via the crankshaft, much like an overhead camshaft. Each sphere rotates against a matching seal between it and the piston, one for intake and one for exhaust.

The spheres have cavities and ports machined into them for the induction of fuel and air on the intake stroke, and the evacuation of fired gases on the exhaust stroke. This design performs exactly the same function as poppet valves, but the design eliminates the poppet valves, valve springs, guides, camshaft, pushrods, rocker arms and other smaller parts.



The Coates engine operates with over 100 fewer parts than convention engines. It avoids the problem of oil burning by requiring no oil lubricants for the valves. Moreover, the rotation of the spherical valve heads reduces engine temperature by constantly changing the surface exposed to combustion heat.



The spherical rotary valve design can accommodate higher compression ratios than conventional engines. High compression ratios can be utilized incorporating the Coates more efficient and powerful short-stroke design, while maintaining the desirable characteristics of optimum performance using lead-free gasoline. The maximum rpm on the poppet valve engine were 5700 rpm. Plus, there are fewer components and thus lower costs.

http://www.coatesengine.com/

HuskyRips said:

thats a really cool setup and I have been watching it for years wondering if it would ever take off. Even contacted them several years ago to see if they would sell me a single cylinder head to graft on a 4 stroke motorcycle. No interest in that and if so big $$$ they had big issues sealing it on the compression stroke but some floating seal ring fixed the issues I guess. Cool stuff.

You and I should never get together for a chat as it would be an engineering geek fest. :lol: