Rokon motorcycle
Encyclopedia
Rokon is a Rochester, New Hampshire
-based motorcycle manufacturer that builds unusual 2-wheel-drive off-road motorcycle
s which are sometimes referred to as Moto-tractors.
by Orla Larsen in 1963 to sell the Nethercutt Trail-Breaker, a 2-wheel-drive motorcycle invented around 1958 by Charlie Fehn and built in Sylmar, California
. In 1964 Rokon Inc. bought the manufacturing rights to the Trail-Breaker and marketed the bikes from their Vermont office before moving the business to New Hampshire
, where they continue in business today.
(US Motor/Chrysler Marine) 820 2-stroke engine (134cc), while newer machines have either a Honda or Kohler engine of about 6hp. The wheels are able to hold gasoline or water for long distance trips.
These are slow-speed off-road motorcycles designed for use in the most rugged terrain. Some are capable of 35mph or more, but typical top speed is about 20 mph. Current models are the Trail-Breaker, Ranger and Scout. However, going up very steep hills the bike may only travel at 0.5 mph.
, rear wheel drive only, and dual disc brakes. Another unusual feature was a pull cord to start the engine. The transmission freewheels with the engine at idle; starts to engage about 2800 RPM; and is tuned so the engine always runs near peak power, at 6,000 to 6,700 RPM. The lowest gear ratio is 3.76:1 and highest 0.87:1. Using a CVT allows a use of a 2-stroke cycle motor with higher power but narrow power band. The engine sound is unusual as the engine stays at a nearly fixed speed and the transmission ratio changes according to speed. The transmission freewheels when not driving forward, so there is no engine braking. The transmission is vented to the outside for cooling, and so is contaminated by stream crossings and other environmental exposure. Water causes slipping but quickly goes away; however grit can cause transmission sticking. Riding on loose surfaces is sometimes complicated, as rear wheel breakaway does not cause telltale changes in the engine sound. However, most other riding is intuitive and sometimes much more convenient as the automatic avoids engine stalls and other problems with gear selection. Operation is loud (90.3 dB(A)) as the engine is always running fast except at idle. Despite low front wheel weight, about 43%, it had trouble pulling wheelies, a problem for the targeted Enduro riding. Prototypes were raced by factory riders from 1971 to 1973 under Tom Clark; "TCR" stands for "Tom Clark Replica". In the 48th annual six-days trial, all four riders earned bronze medals for finishing. "Cycle Guide" test riders reported it superior for hill climbing and fast on hard surfaces, but poor on loose surfaces and going down hills.
Rochester, New Hampshire
Rochester is a city in Strafford County, New Hampshire, United States. As of the 2010 census, the city population was 29,752. The city includes the villages of East Rochester and Gonic. Rochester is home to Skyhaven Airport and the annual Rochester Fair....
-based motorcycle manufacturer that builds unusual 2-wheel-drive off-road motorcycle
Motorcycle
A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...
s which are sometimes referred to as Moto-tractors.
History
Rokon was founded in VermontVermont
Vermont is a state in the New England region of the northeastern United States of America. The state ranks 43rd in land area, , and 45th in total area. Its population according to the 2010 census, 630,337, is the second smallest in the country, larger only than Wyoming. It is the only New England...
by Orla Larsen in 1963 to sell the Nethercutt Trail-Breaker, a 2-wheel-drive motorcycle invented around 1958 by Charlie Fehn and built in Sylmar, California
Sylmar, Los Angeles, California
Sylmar is a district in the San Fernando Valley region of the City of Los Angeles, California. The northernmost neighborhood in the city, Sylmar is located east of Interstate 5 and north of the city of San Fernando...
. In 1964 Rokon Inc. bought the manufacturing rights to the Trail-Breaker and marketed the bikes from their Vermont office before moving the business to New Hampshire
New Hampshire
New Hampshire is a state in the New England region of the northeastern United States of America. The state was named after the southern English county of Hampshire. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Atlantic Ocean to the east, and the Canadian...
, where they continue in business today.
Design
Rokon motorcycles use a combination of belt, chain, and shaft drives coupled to gear boxes to drive both the front and rear wheels. Older machines were powered by a West BendWest Bend Company
The West Bend Company was a West Bend, Wisconsin company from 1911 to 2003. It manufactures aluminum cookware and electrical appliances, but also made two-stroke cycle engines including outboard boat motors. Art Ingels used a surplus West Bend engine to power the first kart...
(US Motor/Chrysler Marine) 820 2-stroke engine (134cc), while newer machines have either a Honda or Kohler engine of about 6hp. The wheels are able to hold gasoline or water for long distance trips.
These are slow-speed off-road motorcycles designed for use in the most rugged terrain. Some are capable of 35mph or more, but typical top speed is about 20 mph. Current models are the Trail-Breaker, Ranger and Scout. However, going up very steep hills the bike may only travel at 0.5 mph.
RT340 TCR Automatic/CVT
In 1974, Rokon produced the RT340 TCR Automatic, using a snowmobile-type Salsbury CVTContinuously variable transmission
A continuously variable transmission is a transmission that can change steplessly through an infinite number of effective gear ratios between maximum and minimum values. This contrasts with other mechanical transmissions that offer a fixed number of gear ratios...
, rear wheel drive only, and dual disc brakes. Another unusual feature was a pull cord to start the engine. The transmission freewheels with the engine at idle; starts to engage about 2800 RPM; and is tuned so the engine always runs near peak power, at 6,000 to 6,700 RPM. The lowest gear ratio is 3.76:1 and highest 0.87:1. Using a CVT allows a use of a 2-stroke cycle motor with higher power but narrow power band. The engine sound is unusual as the engine stays at a nearly fixed speed and the transmission ratio changes according to speed. The transmission freewheels when not driving forward, so there is no engine braking. The transmission is vented to the outside for cooling, and so is contaminated by stream crossings and other environmental exposure. Water causes slipping but quickly goes away; however grit can cause transmission sticking. Riding on loose surfaces is sometimes complicated, as rear wheel breakaway does not cause telltale changes in the engine sound. However, most other riding is intuitive and sometimes much more convenient as the automatic avoids engine stalls and other problems with gear selection. Operation is loud (90.3 dB(A)) as the engine is always running fast except at idle. Despite low front wheel weight, about 43%, it had trouble pulling wheelies, a problem for the targeted Enduro riding. Prototypes were raced by factory riders from 1971 to 1973 under Tom Clark; "TCR" stands for "Tom Clark Replica". In the 48th annual six-days trial, all four riders earned bronze medals for finishing. "Cycle Guide" test riders reported it superior for hill climbing and fast on hard surfaces, but poor on loose surfaces and going down hills.