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Customs JRL Cycles' Radial Chopper

Tuesday, April 17, 2007
John Levey s stint in aircraft mechanics school introduced him to the inner workings of the radial engine and stoked the fires of creativity necessary to complete the build.
JRL Cycles initially built the Radial Chopper 'just to be different' until realizing the radial engine ran smooth, had minimal vibrations and tons of torque.
John Levey didn't go to aircraft mechanics school to learn to build motorcycles. Yet there is no control over the impetus for inspiration. Epiphanies by nature are unpredictable. Little did Levey know that his introduction to aeronautics would lead to the Radial Chopper, but while learning the intricacies of the radial engine, the idea to build the motorcycle ignited.

"That would be so cool on a bike," Levey surmised. We concur. It is cool.

Levey gives much of the credit to his brother-in-law, Mike Wherle, an old-school bike builder from the mid-'70s, and his shop partners, Tim Deml and Chet Thomas. What started out as bar talk between friends blossomed into rough sketches on a bar napkin. Levey still has the initial drawings Wherle whipped up, complete with beer stains on them.

Wherle and Levy drew up the initial designs at the Sturgis Rally in 2005. Soon after, they got the Rotec motor in November of 2005. The bike was done a little bit before Sturgis kicked off again in 2006. The actual build time on the Radial Chopper took around nine months. The end product was surprisingly close to the initial drawings.

For the build, one of the first issues to arise was simply finding the right engine. Most radials Levey had seen up to then were too big. Then he came across the Australian-sourced Rotec R2800. After deciding that the motor would work for what they envisioned, Levey initially wanted to mount it crossways, the same way Jesse James placed a Rotec in his version of a radial-engined motorcycle, 'Radial Hell.' His brother-in-law changed his mind.

"We're not building an airplane. It has to be this way (inline)," Wherle said.

Wherle's advice was instrumental in the build. With the engine's cylinders placed inline with the wheels, the drive system is simpler than coming off the back of the motor and having to turn the direction of rotation two or three times in order to transfer power to the rear wheel. It also puts riders in a normal, comfortable riding position without having their feet right behind the motor, and it allowed JRL Cycles to use the forward controls.

Levey related the story of when the frame and motor were first being unloaded off the truck. The initial reaction from friends was a blank stare into the crate followed by exclamations of "Wow." Levey replied, 'Yeah, now we're going to put that in there (pointing to the frame)."

By mounting the engine inline with the wheels instead of crossways  JRL was able to use the forward controls and kept modifications to a minimum.
The Radial Chopper, with its Rotec 2800cc 110hp aircraft engine, turned heads at the Oshkosh Air Show.
But how do you get a 2800cc 110 horsepower engine with a circumference of roughly 31.9 inches mounted in a frame? It took some experimentation, but JRL was finally able to produce a backbone correctly configured to support the Rotec engine. The first one they had fabbed up was done locally and the piping was huge and had kinks all the way around, but Levey was vigilant. JRL eventually had to have the backbone bent down in Denver where they had more resources and the capability to bend the thick-walled tubing.

Soon after dealing with that dilemma, another challenge presented itself. Due to the equipment they had for the build, getting the motor aligned and straight and mounted was proving difficult. It got to the point where Levey had to say, "Hold it and weld it" before it went in. Amazing what a can be accomplished with a blow torch.

For the next task, JRL constructed an adapter plate and put the plate where the propeller pad used to be. This trimmed about 30-40 lbs of reduction gearing from where the propeller was. The JRL-patented adapter plate accepts a pulley, so the next obstacle became finding a belt long enough. The primary drive is at least six inches longer than any Harley out there. It took months of searching, but Levey found one without having to have one custom made. It puts the transmission right up between the cylinders. Better yet, he said that it lined up surprisingly well. Also, with the direction of rotation for the crankshaft running inline with the wheels, it avoids the problem of engine torquing the bike sideways when revved up.

Assembling the rest of the drive was straightforward. Levey used a standard Baker six-speed right-side drive. The only changes that had to be made on the Baker were to offset the final-drive pulley, which moved the transmission over about a half-inch to the left. This made room for the extended length Primo Brute 3 1.75-inch-wide belt primary drive.

The primary and the covers were put on just before Sturgis. For the next build, JRL will have the luxury of spending more time on it, equipping it with standard-looking primary drive covers. They've already lined up a new supplier, R&D Billet out of Minnesota, who specializes in custom drives. Levey also considered making covers for the spark plug wires, but in the end decided to leave them exposed. He did decide to put on a small, round Harley-style air cleaner.

The Rotec 2800cc engine has a broad powerband. Though 110 hp for a 2.8-liter engine doesn't sound like much, it pulls like a thoroughbred as it boasts 160 lb-ft of torque, almost twice as much as a stock V-Twin. Levey claims that it will pull just as hard in second gear as it does in first and won't top out until it approaches 100 mph. First gear is good for more than 50 mph.

The Rotec radial engine is a 2800cc motor with a claimed hp of 110 and loads of torque.
So how do you get an engine with a 39-inch circumference into a custom frame? For JRL Cycles, it meant three attempts at having the backbone bent and a little help from a welding torch.
"I don't think the bike will ever see sixth gear," Levey chuckled.

One of the major differences between a radial and a V-Twin is the intake. Practically all radials have an impeller mounted to the end of the crankshaft that atomizes the fuel and spins it out to all seven cylinders but doesn't really pressurize anything. A lot of people don't realize that and think that it's got to go through a lot of curves to get up to the tall cylinders, which is not the case.

Currently the Radial Chopper runs an altitude-compensating 40mm Bing carburetor. The Bing isn't that big, so on the next one, they plan on switching over to a larger S&S carb that Levey claims will fit better underneath.

Being a radial, it does start up in a puff of smoke. Levey explained that there's going to be a little smoke turning it over no matter what you do because you have cylinders that are always upside down. The biggest concern with the radial is oil control and keeping it out of those cylinders. It does use a lot of oil. This is where a five-quart oil tank comes in handy.

When asked about its fuel efficiency, Levey confided that it burns more than a V-Twin, but for its size it probably burns in the range of a big-stroked V-Twin. The gas tank holds only 2.5 gallons, "Which gets you about an hour's worth of cruise time," Levey laughed. JRL put the tank in the conventional location, which turned out to be a nice setup as it eliminated the huge mechanical fuel pump that Rotec had bolted to it.

The bike's front end is raked out enough that it prefers to go in a straight line, with a total rake of 50-degrees (43-degrees on the frame, 7-degrees on the tree). It was a few degrees more than Levey wanted, but in his conversations with Roger Goldammer, Goldammer said the bike needed the extreme rake angle to make it stable. Levey has been corresponding with Goldammer via e-mail and has sent him pictures during different stages of the build. He uses a Goldammer Cycle Works fork on the Radial Chopper. When asked about his correspondence with him, Levey had nothing but good things to say about the Canadian master builder.

"He has turned out to be a great guy to work with, especially just starting out not knowing many people in the industry."

When he went to fire up the engine for the first time, Levey was amazed at how well-balanced it was. He thought he might have to strap it down to keep it from beating itself to death, but it ran incredibly smooth. He compared the vibration to his trusted 1980 Honda 750.

JRL Cycles  John Levey says he gets e-mails from pilots who likewise thought about the possibility of building a bike with a radial engine but never had the means to see their ideas to fruition.
JRL Cycles' John Levey says he gets e-mails from pilots who likewise thought about the possibility of building a bike with a radial engine but never had the means to see their ideas to fruition.
The Radial Chopper debuted publicly at the EAA AirVenture Oshkosh Air Show in 2006. The event enjoys a draw the magnitude of Sturgis (almost 800,000 visitors per week, according to Levey). Ignition trouble at the air show prevented them from starting the bike. A module on the connection to the electronic ignition system got banged up and bent. Being an aircraft engine, it has two ignition systems in case one of them fails. The first is electronic, which is the main setting if the engine is used for applications like the Radial Chopper. The second is a magneto backup. The bike fires up clean now and JRL plans to return to Oshkosh to give the crowd a taste of what they missed last year.

As far as future projects go, JRL has a 9-cylinder radial trike in its sights, starting next year some time. Levey has been watching the popularity of trikes rise. MCUSA has seen the evidence of this trend, posting a piece recently on the Lehman Trike and, on a similar note, the sporty three-wheeled Can-Am Spyder.

Before the trike, though, JRL is building a softail for a contract pilot, Ollie Staffield. The next design is going to be much different. It will stress the motor as part of the frame. This will do away with a cage JRL built that runs down the right side of the bike behind the exhaust that picks up the factory airplane mounts. This is where its partnership with Rotec is going to help out. Rotec is redesigning the motor for them, putting on different mounts and narrowing the engine about five inches, which will speed up the mounting process. JRL will use a custom primary by R&D Billet, and Levey mentioned that they were going to put the starter on top of the tranny, which should help lower the bike's overall center of gravity.

For Staffield's bike, JRL plans on stretching out the softail a little more. The original is nine feet long, and Levey's toying with the idea of something in the 10-foot range. The tank will be widened also to slake the radial's thirst. JRL chose not to throw down for wild custom paint on the Radial Chopper because they wanted the engine to be the star attraction, but Staffield has plans for a WWII-themed custom airbrushing job to be done on his bike. It should be done in time for Sturgis 2007.

If you want to see the Radial Chopper in person, Levey plans on taking the bike to the Oshkosh Air Show again this year, which runs from July 23 - July 29. They also have a beneficial relationship with Staffield, a contract pilot who flies over in Afghanistan. Staffield is gone for three to four months at a time and has given JRL the go-ahead to show his bike while he's gone. When he comes back, he wants to show it himself. He lives in Virginia Beach, so JRL's work will enjoy a little East Coast exposure that it might not otherwise receive since their shop is located in Black Hawk, South Dakota.

Levey is in the process of nailing down a national sponsor to help cover shop expenses. In addition, he plans on showing the Radial Chopper more. Levey just had a meeting with Budweiser and will be conducting a model search every weekend next month sponsored by Bud, JRL and a local radio station. Before it was all over, we had to ask Levey "Why? Why build a radial bike?"

What better place to debut a bike with an aircraft-inspired radial engine than one of the elite air shows in the country  the EAA AirVenture Oshkosh Show.
The Radial Chopper, with a calculated top speed over 200 mph, would look good in any Top Gun's garage, especially if it attracted the attention of the ladies.
"It started out just to be different," Levey said. "It ended up being a real sweet motorcycle motor. There's virtually no vibration. Loads of torque. Sounds great, too.

We pressed him further with our questions, asking him whose bike design is better, his or Jesse James' "Radial Hell." Levey laughed.

"How about if I say ours appears to be more practical?" Levey said jokingly. "If radial bikes can be considered practical. I think ours flows better."

JRL must be doing something right. They are the only current factory authorized radial engine motorcycle manufacturer in the United States. Rotec wouldn't have given them the go-ahead to be a rep for its product unless they were convinced of JRL's abilities.

Levey's work proves you don't have to have your own TV show or marry a mega-star to build a radial-engined motorcycle. Sure, the bonus bling that accompanies fame can't hurt. But serving a stint in aircraft mechanics school doesn't hurt either.

We'd love to put the Radial Chopper on the line against Radial Hell. How about it Jesse? Give Leno a call. He can drop the flag and buy the winner for his collection.

We'd like to hear your take on the Radial Chopper in the MCUSA Forum. Click Here
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Specifications for the Radial Chopper
ENGINE
Displacement: 171 cubic inches, 2800cc
Horsepower: 110
Cases: Rotec Engineering
Flywheels (make & stroke): Rotec 3.15"
Balancing: Naturally
Connecting rods: Straight up master (solid rod #1 cylinder) all other rods articulating to the master rod assembly - all rods use the same bearing.
Cylinders (make & bore): Rotec 3.15"
Pistons (make & comp. ratio): Rotec 8.5:1
Heads: Rotec billet aluminum
Cam (make & lift): Rotec cam ring
Valves, rockers, lifters, pushrods: Rotec
Carb: Bing 40mm altitude compensating
Air cleaner: JRL
Exhaust: All Metal Manufacturing / Exhaust Pros of Rapid City
Ignition: Dual ignition magneto and electronic two plugs per cylinder
Coils: Stock automotive
Charging: ND alternator
Regulator: ND
Oil pump: Rotec mechanical supply pump and VDO electric scavenge pump
Cam cover: Rotec
Primary cover: JRL

TRANSMISSION
Year/model: 2005 Baker RSD
Gears: 6 speed overdrive "R" Ratio
Mods: 1" offset final drive pulley
Clutch: Hydraulic
Primary drive: JRL / Primo extended length 1.75" wide 8mm
Final drive: extended length 150 tooth belt 65 rear pulley

CHASSIS
Frame: JRL / Daniel Gylten / All Metal Manufacturing
Rake: 43 degrees in the neck, 7 degrees in the tree
Stretch: 6"
Front forks: Goldammer
Front wheel (size and make): Sturgis 21"
Rear wheel (size and make): Sturgis 18"
Front brake: 13.5" PM rotor and 6 piston caliper with Sturgis Wheel inner section
Rear brake: PM caliper and Sturgis Wheel rotor drive side
Front tire (size and make): 90 / 90 21" Avon
Rear tire (size and make): 300 / 35 R18 Avon
Front fender: Milwaukee Twins
Rear fender: JRL / Milwaukee Twins

ACCESSORIES
Headlight: Adjurl 5.75"
Taillight: JRL
Fuel tank: Twisted Choppers
Oil tank: 5 qt
Handlebars: Harley Davidson V-Rod
Risers: JRL 3"
Seat: Roy Keith Classics
Pegs: Milwaukee Twins
Speedo: Functional Air Speed Indicator
License bracket: JRL
Hand controls: Excel
Foot controls: Milwaukee Twins

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Comments
Diozark   July 27, 2013 07:33 PM
That is a work of art, and You can ride it. Awesome!
browing -What a fighter!  December 13, 2009 08:02 AM
It's so great that ride this wonderful machine just like flight the fighter!
Stuart McCulloch -Radial chopper  September 25, 2009 07:47 AM
Awesome bike, radial engine made not far from my home here in Australia, would like to see one crusing the highway down under! Good work by all
sanjay rai -can't beleav  June 24, 2009 04:22 AM
can we just imagine this is all bikes.... no neva.... what a revolution of byes.. realy heading towards fucking cool bykes..
conrad feltro -RE: RADIAL CHOPPER  May 21, 2009 11:11 AM
EXOTIC, AWESOME CHOPPER. BEST ONE I'VE EVER SEEN! I LIKE HOW THE RADIAL ENGINE FILLS IN ALL THE GAP BELOW THE "COBRA" LOOKING GAS TANK! SWEET, ALOHA!
Rob Fernandes -Flight Plans  May 1, 2009 08:36 AM
Since this is such an innovative concept bike I should expect to see it at a car show at a Civic Center in my area sometime in the future.
Geser Ribeiro -Increable!!!!!!  January 8, 2009 08:21 PM
I hadn't ever seen something looked it..... It's wonderfull ... like the Classical Aviation of the Second Global War. Congratulations John Levey and all JRC Cycles.