The Kneeslider

Doers Builders and Positive People

Mazda Rotary Engine Motorcycle

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Mazda rotary engine powered motorcycle

Got an interesting photo yesterday of this rotary motorcycle sent in by a reader looking for more information. I don’t have all of the details yet but I thought I would put this out for everyone to check out and see what you thought of it.

The rotary engine is from a Mazda and is the 2 rotor variety, which may be all they make for all I know, I’m not up on my rotary engines. The rear end is BMW and the front end is from a GSX-R. The bike was on display at 7 Stock, which is a gathering of rotary engine owners and enthusiasts and was next to the Mazdatrix booth.

I was told by Mazdatrix the bike was built to this point in a bit of a hurry so it could be on display at the show, whether the bike has since been finished I can’t say. It did start and run and was extremely loud, not surprising when you look at the stubby headers. Judging from the position of the footpegs on the right, the rider’s feet might get a bit warm but that could all be changed as the build progresses.

It’s an interesting project. There haven’t been many custom rotary motorcycles around that I know of so as an exercise in something new, this is pretty neat. I’ll post more information as I get it or if any of you happen to have more information let us know.

Thanks for the photo, Brett.

UPDATE: Finished

Posted on Filed Under: Engines, Motorcycle Builders, Motorcycle Design

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Comments

  1. Now that is unique. It also happens to be just what I was looking for….a way to use a 12A rotary with a motorcycle drivetrain. I’ve got a 3-wheeler project on a napkin that requires just such a drivetrain as this motorcycle has, and the rotary and a turbo kit for it sitting in my garage.

    Anyone got more info on this beastie?

  2. Check out “Rotomax.” They are lauching a bike called the Rotabike using the rotamax rotary engine. It is not quite a bold as the Mazdatrix bike.

  3. That’s one of the craziest awesome things I’ve seen in a while. I wonder what it uses for a transmission.

  4. From memory, rotary engines have two power strokes and one dead stroke. I know that there was a rotary built with 3 rotors, resulting in almost perfectly smooth power delivery. However most rotary engines are built by Mazda, and they almost always have the two rotors. All I know is they’re bloody loud, and bloody powerful.

  5. there is a 3 rotor for the japanese market (i think the model is called the cosmo) and they used a 4 rotor to win lemans. I’ve heard sound bites of a 3 or 4 rotor from an aftermarket company that builds them for the import crowd. it sounded GOOOD! kinda like an f1 motor with a hint of 2 stroke.

  6. wicked bike. Make a custom chopper raked out forks and a 13b pp and i ida for induction. 300hp at the wheels would be insane. Dunno bout those water pipes and side draft by the exhaust tho. wicked concept mate looke the part aye. must haul ass.

  7. It’s an interesting concept, but not very practical. I have a 12A sitting around, and thought about this but there are some problems…

    First of all, the crankshaft is arrayed longitudinally, rather than laterally. This is because the 12A and 13B engines are physically too large to practically turn sideways, so this was the only way they could get it to fit.

    I’ve actually pitched this idea to JT Nesbitt: something like a Wraith but with a rotary engine. Water cooled, transversely mounted 1000cc four rotor engine. Modern fuel injection, engine management, and high flow catalytic converters would keep the EPA happy without dampening performance.

    I’ve seen the Rotabike, and it makes me a little sad. It’s cool that somebody has built an American rotary powered motorcycle, but why, why, why do people insist on building hard tail choppers?

  8. how about a single rotor with a little turbo hanging out? you could probably even put it transversely that way. there would still be some packaging issues and who knows if the power/weight/size would actually have any benefit over more “normal” layouts. but who cares? you’d have a sweet turbo rotary powered MOTORCYCLE!!!

  9. guitargeek – the rotabike is a softtail and has a full rear suspension. And it’s hardly a chopper. It’s a standard american motorcycle.

  11. I had this idea a few years ago. Wanted to build a prototype, but money constrictions have stopped me. Looks like someone beat me to it.

    The biggest problems I came up with were the transmission (possibly an old BMW transmission could work) and the lateral momentum caused my the engine rotation – it’d suck to gun it and have the bike flop on it’s side…

  14. Yeah, there’s a Suzuki RE-5 for sale in my city for $1,500. I’d snap it up in an instant if I could afford it. Rare bike.

    I like the some of the last Norton designs featuring rotary’s the best. Here’s hoping to Triumph buying up the Norton name and reviving the rotary powered Norton’s…… I know I’m dreaming now though…

  17. so take the engine out of an rx8. turn it sideways hook it somehow to the existing tranny in the gsxr and run the piss out of it..easy, right?

  18. THIS BIKE IS WICKED AND WOULD DEFFENTLY HALL ARSE.. WOULD LIKE TO KNOW SPECS OF IT CAUSE EVEN A 12APP (1.2 LTR 2 ROTOR WITH BIGGER INLET AND EXHAUST PORTS)WOULD PRODUCE MASIVE AMOUNTS OF POWER ESPECHIALLY WITH 48MILL IDA GILMORES AND BIGGER FUEL PUMP/LINES YOU CAN GET THEM DOING HIGH 10S LOW 11S DOWN THE 1/4MILE IN A STATION WAGON IMAGINE THE TIMES IN A 250KG FRAME PURE POWER AND 160DB OF PURE LOUDNESS

    KEEP ON RUTTIN NZ TANGIN “RUT RUT RUT”

  19. I have a 75 Suzuki RE-5 rotary bike I had built for show. Got first and a second at two bike shows and since she’s been sitting. If anyone is interested get me your cell # and I’ll click you a picture. I re-painted her factory silver, and had the matt black areas chromed. All new factory black stripes.