There are engines that have been thought about. Rokon engines are an example of this. The American factory that became known for off-road vehicles with 134 cc West Bend and later Chrysler two-stroke engines that were actually designed as an outboard engine.
From 1975 onwards, off-road motorcycles were also made with 335 cc Sachs engines, which in some cases had an automatic gearbox. The Trail Breaker is very special, a two-wheel drive engine with large hollow rims, which serve as floats in the water, but could also be filled with 17 liters of water or gasoline.
Rokon was founded in Vermont in 1963 by Orla Larsen to market the Nethercutt Trail-Breaker, a two-wheel drive motorcycle invented by Charlie Fehn around 1958 and built in Sylmar, California. In 1964, Rokon Inc. purchased the manufacturing rights to the Trail-Breaker and began in-house production in Vermont before moving to New Hampshire, where the company remains based.
Rokon motorcycles use a combination of belt, chain and axle drives, linked to gearboxes to drive both the front and rear wheels. Older machines were powered by a West Bend (US Motor/Chrysler Marine) 820 two-stroke engine (134 cc), while newer machines have a Honda or Kohler engine of about 6 hp. Each wheel is a 'jerry can' for about ten liters of petrol or water. Because with a Rokon you never know where you will end up. Oh yes: the wheels appear 'empty' like floating bodies. They allow the Rokon to float on its side.
Rokons are slow off-road motorcycles designed for use in the most rugged terrain
Some are as fast as 50 km/h, but the average speed is about 30 kilometers per hour. And when climbing a really serious slope, the speed can simply drop to 1 km/h.
With the stepless transmission of a snowmobile
In 1974 Rokon produced the RT340 TCR Automatic, using a Salsbury CVT snowmobile transmission, rear wheel drive only and dual disc brakes. The pull cord to start the engine was also something more familiar to snowmobile riders than to motorcycle riders. The transmission idles down to about 2800 RPM; and is tuned so that the engine always runs close to peak power, at 6000 to 6700 RPM. The lowest gear ratio is 3,76:1 and the highest is 0,87:1. The use of a CVT allows the use of a 2-stroke engine with more power and a narrower powerband. The transmission freewheels when it is not driven, so the Rokon does not brake on the engine. The transmission is ventilated to the outside for cooling and this 'open' construction makes it sensitive to outside contaminants. Water causes slip but disappears quickly; however, grit can cause transmission seizure.
No feedback due to the speed
Driving on loose surfaces is not that complicated, but causes some confusion at first because a slipping rear wheel has no effect on the engine speed. Such a Rokon does make a loud noise (90,3 dBa) because the engine is by definition high in speed, except when idling. Despite the low weight on the front wheel (about 43%), such a Rokon has little desire to pull wheelies, and that is a problem for Enduro riding when you want to bounce over something.
It has been raced with
Prototypes were raced by factory riders from 1971 to 1973 under the Tom Clark banner; “TCR” stands for “Tom Clark Replica”. In the 48e During the annual six-day event, all four riders won bronze medals. Regular test riders reported enthusiastically about its climbing ability and ride over hard surfaces, but criticized its handling on loose surfaces and downhill hills.
Here in the Netherlands, Rokon's rare appearances
We recently saw one at Dutch Lion Motorcycles. Rokons are - just like Landrovers once were - machine tools rather than vehicles. But they are very nice.
Looks like a private hobby project.