The early ‘70s were a heady time for dirt bike development. We live in an era when bold new graphics are a big deal on the showroom floor. Fuel injection is great, but then again cars have had fuel injection for 60 years and aircraft since the 1930s. It seems nothing is new these days, but the world of 2011 is a vastly different place than it was in 1970. In 1970 anything seemed possible! Thinking outside the box was the norm, and nobody thought further outside the box when it came to dirt bike innovation than a tiny company in New Hampshire, USA.

Well known for their funky two-wheel drive Rokon Trailbreaker ATVs, Rokon decided to expand and cash in on the growing dirt bike market by developing a line of ‘normal’ motocross, enduro and dual-sport bikes…if the engineers at Rokon could ever be considered normal.

1974 Cycle Illustrated cover. “The Husky Eater.” You can find magazine treasures like this by visiting www.dadsvintageads.com

The radical machines they came up smashed the status quo of motorcycle design. In an era of pipey, piston-port two-strokes with hand grenade reliability Rokon used a simple 340cc Sachs snowmobile engine. Transmission? What could be easier to use than a snowmobile-style Salsbury clutch? Thanks to that infinitely variable CVT system Rokon engineers didn’t have to worry about a peaky powerband; they could tune the engine for maximum power and adjust the clutch to keep the engine revving at the power and torque peak all the time.

Rokons sound weird because they are always on the pipe…like a snowmobile. Go figure. That’s ‘Rokon Mike’ Murphy cranking the throttle on his RT-2/Cobra hybrid vintage racer.

But there’s a funny thing about CVTs when it comes to coasting. With little to no engine braking the Rokon needed more than the crummy mechanical drums so common on vintage bikes. On went hydraulic discs. As anyone with a vintage dirt bike knows those 70’s wheels with small gauge spokes were a constant nightmare, so Rokon developed a set of lightweight cast magnesium wheels. What was the result of all this weird science? A chubby but effective bike that in various forms won a whole bunch of ISDT medals, industry accolades for outstanding engineering and even earned AMA national motocross success.

Jim Hollander in the Italian Alps in 1974, on his way to a silver ISDT medal.

It was around this time that my personal interest in Rokons was formed. As a little kid wandering around at gas stops at enduros in Ontario and Western New York I was drawn to the strange bikes with their pull starters and weird looking wheels. I’d pester Rokon owners with questions like, “Why can I see the gas through the gas tank?” and “What are those big circle things where the brakes are supposed to go?” Running over to watch Rokon riders pull start their bikes was a constant source of amusement for me at six years old! I even liked the cast wheels, because they reminded me of the ‘Motomag’ wheels the cool kids had on their Mongoose BMX bikes.

1974 Rokon MX-1 in action at the Gopher Dunes VMX race in 2009. Curious spectators crowded around this bike in the pits all day.

Unfortunately by ’77 the Rokon ride was over. It’s a real shame because in many ways the final Rokon prototype RX500s were three decades ahead of their time!

The last 1977 Rokon RX500 prototype still exists, rescued from oblivion by Jim Hollander.

They had a disc brake mounted on the drive sprocket, which in turn was inline with the swingarm pivot. You can consider the stillborn ‘77 Rokon RX500 sort of like a cross between an ATK of the early ‘90s and a current BMW or Husky 450F. Also, like the cutting-edge Beemer and Husky, the final Rokon prototype’s fuel tank was under the seat and the airbox was under the fake gas tank. If the first models were full of new ideas then the final prototype was a full-blown revolution in motorcycle design!

Someone in New Hampshire had a crystal ball! The RX500 prototypes had a 501 Maico top-end grafted to a Sachs bottom end. Having the drive sprocket inline with the swingarm pivot, a countershaft-mounted rear disc brake, an aluminum gas tank under the seat and an airbox under the fake gas tank made the RX500 a lesson in mass centralization. Rokon’s ideas predated the cutting edge 2011 Husqvarna TC449, BMW G450X or Yamaha YZ450F by well over 30 years!

Without a doubt the Rokons were trick! The problem was finding buyers, who by the mid-70s were getting more conservative. Besides, the Japanese were selling boatloads of quick, reliable and most importantly “normal” dirt bikes. To add insult to injury the new clean-air regulations were effectively killing off Rokon’s line of two-stroke dual-sport bikes. Worst of all Rokon was going broke. Chasing their dream of re-inventing the dirt bike financially drained the company and Rokon was forced to cease production. It was the end of an era of free thinking the dirt bike world would never see again.

This beautifully restored ’76 MX-2 lives in the AMA museum. Yes, that’s a Harley Davidson MX250 right behind it, and yes, I want one of those too!

Rokon eventually recovered and went back to building the 2WD Trailbreakers they continue to produce to this day, but the era of Rokon motocross, enduro and dual sport bikes was history. The idea of an automatic transmission race bike lived on however, and Husqvarna developed an automatic transmission of their own which was raced very successfully into the mid-eighties. But those Auto-Husky’s are another story we’re working on, so you’ll have to wait to read about them.

Rokon full-line brouchure. Notice the braceless handlebars, yet another Rokon idea that would live again 30 years later.

History relives itself through vintage racing, and while Rokons may once have been considered oddities they have since become some of the most collectible vintage dirt bikes. They are cool to look at and inspire endless bouts of ‘what if?’ bench racing in the pits. Mostly, thanks to that awesome CVT tranny, a Rokon rider is practically guaranteed a holeshot in vintage motocross.

We tracked down a couple of Rokon riders from the era, ISDT star Jim Hollander (who later went on to start the Hot Grips heated grip company) and Rokon development rider ‘Rokon’ Mike Murphy, who now runs a small business called Rokon Renew that specializes in building and selling vintage Rokon race bikes, to find out more about these intriguing and historic motorcycles.

Offroadmotorcycles.ca: What inspired you to chose to race an automatic transmission enduro bike?

Jim Hollander: I happen to live just within 100 miles of the Rokon factory in NH, and was asked by the President of Rokon to try out the bike, when I was at the ISDT in Dalton, MA riding a Penton 125. I tried the bike and fell in love with the simplicity and ease of riding it.

Mike Murphy still races his ’76 RT-2 in vintage events, riding it just as hard now as he did back then.

Mike Murphy: A local Rokon dealer needed help, through the factory, on ideas to improve the new long-travel RT-2 model. I suggested taking the Road & Trail (RT) model out on the motocross track with all the dual-sport equipment it came with. They just cut me loose on it to do whatever I wanted, and then would fix whatever I broke. I remember on the drive home from the shop my dad asked me, “Are you sure you want to ride, race & test a 250 lb dirt bike with a pull start snowmobile engine?” After riding the Rokon I knew this machine was the missing link I’d been looking for! I was hooked from that day on.

Did people in the pits greet the Rokon with scepticism or curiosity?

JH: By the time I was on board with Rokon (1973) the bike had already proven itself with four out of four finishers at the ISDT in September 1973, so it was mostly curiosity, not scepticism.

MM: Both. I noticed younger riders like myself, around 22 at the time, made a lot of jokes about it. They even called me ‘The lawnmower man!’ But the older guys were curious about the Rokon and asked many questions.

Mike Murphy’s beautiful 1976 Rokon Cobra 340 motocrosser.

Describe the basic design of the Rokon’s transmission.

JH: Rokon’s transmission is a torque converter set up like on a snowmobile, with a front drive sliding double cone arrangement off the engine crankshaft and then a rear driven torque converter, which was connected to a gear reduction box before output to the countershaft sprocket. It is torque sensing in that as the rear wheel slips the pulleys tend to up-shift into a higher ratio.

Was there a long learning curve when you first rode an automatic, or were you comfortable and fast with it right away?

JH: There was a learning curve of a few weekends at local enduros in New England, but then it was much easier to ride than a shifter bike.

MM: The hardest thing for me about learning to ride the bike was the disc brakes! At that time we all had drum brakes that basically didn’t work very well. The Rokon disc brakes did overheat, but worked well at enduro speeds.

Murphy pins his Rokon between the trees at a vintage enduro.

What were your top results racing the Rokon?

JH: In 1976 I won an US ISDT Qualifier overall in Cass City, Michigan over Dick Burleson, Jack and Tom Penton and the other usual winners. Then in Austria at the ISDT as a member of the six-man U.S Trophy Team I was the top scoring trophy team rider and sixth American.

MM: I raced the same bike I have to this day in all the local hare scramble and motocross races. I never even took the lights off for motocross, but I seemed to always stay up front with most of the fast guys.

What did you feel were Rokon’s biggest advantages? Disadvantages?

JH: No worrying about stalling the bike regardless of the situation, and superior traction in the mud! In deep water there was some slipping on the torque converter drive belt, but we got past that by slotting the belt edges on a table saw so they worked like a rain tire.

MM: Advantages? They always find traction and the disc brakes are great! Disadvantages? No engine braking and that drive belt needs to say dry.

Murphy’s ‘76 Cobra looks lean and tall because it is; Rokon claimed 8.5” of wheel travel and 240 pounds, which is about the real-world weight of a modern motocross 450F.

They must have been interesting bikes to ride. Did you need to learn any special techniques compared to racing a ‘normal’ dirt bike?

JH: Yes, I developed a technique of riding the throttle against the rear brake, a bit like the rally drivers did with rally cars, and it made the bike super fast. The rear brakes required silicone fluid to take that kind of abuse.

MM: If you ride a Rokon and stick with it you can adapt to the changes. I always hear stories about someone who rode their friends Rokon and didn’t like it. Well a short ride is not enough! The more saddle time you get on a Rokon the better you will adjust to riding it.

How were they for reliability?

JH: They were overbuilt, so you could crash them a lot without doing any damage. I felt they were very reliable and was not worried about any particular area when in competition.

MM: My bike is very reliable. Sure it has items that have been changed, but that is what was needed to keep up with the standards at that time. I now offer all these special changes and parts on the custom Rokons that I build to sell to vintage racers.

Aside from the transmission did other parts, like engine top-ends or brakes, wear faster or slower than with normal dirt bikes? How about chains and tires?

MM: Rokons face the same problems as any other dirt bike. Maintenance. Any major breakdowns I had were a direct result of me not doing the proper maintenance…all self inflicted. Tires, chains, tops-ends and brakes wear just like anything else.

“It’s all about proper set-up,” explained Murphy when asked about getting the most out of the Rokon CVT. Like a racing snowmobile, careful tuning with spring weights and ramp profiles makes a huge difference on how aggressively the clutch reacts. The clutches of motocross Rokons were tuned to be much ‘snappier’ than the ones used on their dual-sport and enduro models.

Do you think the transmission of the Rokon would have adapted as well to ‘new school’ enduro with all their extreme and motocross-type elements?

JH: I would be curious to ride a Rokon with modern suspension. I am also very curious about the Christini two-wheel drive system and wonder how the combination would be of an automatic with 2WD!

Most race bikes these days, two or four stroke, have very smooth powerbands compared to pipey two-stroke vintage bikes. Do you think an automatic transmission of some type would still benefit a modern fuel-injected four-stroke? Any opinion why the manufacturers haven’t continued to pursue the concept?

JH: Yes, a modern automatic transmission would benefit a modern race bike. There seems to have been a lot of resistance to automatics, even after Husqvarna won the National Enduro Championship on their automatic in the ‘80s.

MM: My enduro bike has the hi-performance Cobra motor and the Motoplat ignition they used in a limited edition motocross model; only 70 Rokon Cobra MX models were ever made! I like the old “On the Pipe!” motocross-type of power better than the all-around powerband like the motor used in the standard RT-2 model.

35-plus years later Hollander and Murphy remain justifiably proud of the Rokon and all the fresh ideas that went into building them. “Even though I never competed in the ISDT,” Murphy says, “…I always have a good feeling about the accomplishments of the Rokon team when I see a picture or read an article about them. I only hope the improvements we made to the Rokons worked their way up to the team riders. I was never able to meet any factory team members but one, Dave Mungenast.”

The late David Mungenast holds an honoured place in the AMA Hall of Fame. Among his many accomplishments is the bronze medal he earned at the Italian ISDT in 1974 while riding a Rokon for the Canadian team.

Murphy continues, “Dave and I became friends and even rode the Colorado 500 together back in 1995. I still have two black and white photo’s hanging in my shed, one of Dave in Italy and the other of Jim Hollander when he cleaned up and won the overall in Michigan!”

Interested in vintage Rokon enduro and motocross bikes? You can contact Mike Murphy at Rokon Renew by sending an email to [email protected]

Thank you Mike Murphy and Jim Hollander for providing info and photos for this story!