New Rotary Bike

[LowRyter]

https://www.yahoo.com/autos/crighton-cr700w-motorcycle-brings-rotary-125800772.html

https://www.youtube.com/watch?v=Z4UeqXktmOg

The automotive world hasn't seen a rotary engine in production since the Mazda RX-8 was axed in 2012. However, the Crighton CR700W is bringing it back in spectacular fashion in a machine billed as the "ultimate track bike."

In fact, the engine claims to have one of the highest specific power outputs of any naturally aspirated engine in the world. The dual-rotor mill displaces just 690cc, but generates 220 horsepower at 10,500 rpm (and 105 lb-ft at 9,500 rpm), which translates to 319 horsepower per liter. By comparison, the company says, most MotoGP race bikes make around 300 hp.

There are many advantages to a rotary engine. For one, it's extremely compact and needs fewer parts than a conventional piston motor, and the one in the Crighton is comprised of just three moving parts. Due to its simplicity, the entire assembly weighs just 53 pounds. Even with its six-speed gearbox attached, the unit comes in at just 95 pounds.

Combined with a Spondon-derived chassis made from 7000-series aluminum alloy and Dymag carbon fiber wheels, the entire CR700W weighs just 285 pounds. Even a Ducati Superleggera V4 tips the scales at 336 pounds, and it beats even the supercharged Kawasaki H2R in power per pound.

The sticker starts at £85,000 ($116,130)

[GuzziMoto]

That is a cool sounding bike, both literally and figuratively.

There are hurdles to the rotary engine, but it can be so cool.

[Weegie]

Seem to remember back in the Norton Rotary days the displacement measurement is open to question and can be measured different ways, can't be a****d looking it up

Is it just me, it looks awfully long, especially swing arm

Still a lot of nice tech and very interesting.

Greta T's in town at the moment

When you're just back from the Dyno after a remap and doorbell goes

 

 

[Nihontochicken]

Wow, it sounds and smokes like a two stroke!  I'm in as soon as someone loans me $116k.  Any takers?  

[LowRyter]

Nih, I agree that rotaries sound like two strokes.  I think it has to do with the fact that the engines fires combustion every revolution.    But that's just a guess. 

Also, since this bike is meant more as a track tool, it would probably require frequent maintenance.  The rotor seals have traditionally been an issue.  

[Lucky Phil]

5 hours ago, LowRyter said:

https://www.yahoo.com/autos/crighton-cr700w-motorcycle-brings-rotary-125800772.html

https://www.youtube.com/watch?v=Z4UeqXktmOg

The automotive world hasn't seen a rotary engine in production since the Mazda RX-8 was axed in 2012. However, the Crighton CR700W is bringing it back in spectacular fashion in a machine billed as the "ultimate track bike."

In fact, the engine claims to have one of the highest specific power outputs of any naturally aspirated engine in the world. The dual-rotor mill displaces just 690cc, but generates 220 horsepower at 10,500 rpm (and 105 lb-ft at 9,500 rpm), which translates to 319 horsepower per liter. By comparison, the company says, most MotoGP race bikes make around 300 hp.

There are many advantages to a rotary engine. For one, it's extremely compact and needs fewer parts than a conventional piston motor, and the one in the Crighton is comprised of just three moving parts. Due to its simplicity, the entire assembly weighs just 53 pounds. Even with its six-speed gearbox attached, the unit comes in at just 95 pounds.

Combined with a Spondon-derived chassis made from 7000-series aluminum alloy and Dymag carbon fiber wheels, the entire CR700W weighs just 285 pounds. Even a Ducati Superleggera V4 tips the scales at 336 pounds, and it beats even the supercharged Kawasaki H2R in power per pound.

The sticker starts at £85,000 ($116,130)

A work colleague of mine bought a second hand low klm RX8 for his wife. All good till 80,000klm and he started complaining about very hard starting when cold. He did lots of work on it such as plugs, ignition leads other stuff, very frustrated. He eventually took it to a Mazda Rotary specialist. He walked in the door and saw 3 RX8's sitting there with the engines out. He explained to the specialist his issue and he said straight away, "yep it needs a rebuild". Apparently it's typical and the rotary engine and they only go around 75,000 klm before requiring new seals and rotors at the very least, so basically a full rebuild. The other three cars there were in for the exact same issue. He had it rebuilt and sold it off. I've driven an RX3 and it was quite awesome at the time but I don't think the Rotary is a practical proposition even in a track bike personally.

Ciao   

[Rox Lemans]

I would say it's pricy but it's a superlight track bike with 220hp and 105ft lbs. That's almost motogp numbers for just over $100k. 

[p6x]

I was still at school when Citroën came to present the GS Birotor, if you follow the link, less than 1000 were ever built, and of those who drove one, they had to get a full engine rebuilt around the 20,000 km mark. 

Anybody here remember the Suzuki RE5? if you follow the link, apparently this guy own and operate one still today.

 

[LowRyter]

I'd just wonder if the engine could be designed to service in modular fashion on a motorcycle.  Pull out the side of the motor, pull out the crank and rotor, install another one?  (Similar to pulling the clutch on a transverse motorcycle engine.)   Reinstall the crank/rotor and the side case.  Service the old rotor seals for the next change out.

 

No?

[GuzziMoto]

The thing with the displacement has to do with the difference in rotation of the crank vs the rotors. I seem to recall it is like a three to one relationship between crank rotation and rotor rotation. For every three rotations of the crank the rotor makes one rotation. Compare that to a piston engine, which would be equal to two to one as far as measuring displacement goes (in two rotations of the crank the engine would displace its swept volume of all the cylinders added up). Add to that each rotor has three "combustion chambers", so each rotor could be considered a three cylinder bank. In one full rotation of the rotor (equaling three rotations of the crank) each rotor fires three times. So, it is tricky to directly compare the displacement of a rotary directly to a four stroke piston engine. They just aren't a one to one comparison.

But the result is, a twin rotor rotary sounds like an even firing interval six cylinder engine that revs to crazy high rpms.  Throw a four rotor engine into the mix and it is getting near old school F1 V12 territory.

They aren't really about longevity, but they can pack a lot of power into a small, light, package. And while they do wear out faster, they also have fewer parts to fail so they usually don't suffer from sudden premature failures.