The Trail-Breaker, if you haven’t seen one before, is a two-wheel drive, go anywhere motorcycle. It makes the GS look like a Rocket 3.
The genesis of these machines goes back to an early patent submitted this day in 1958 by Charles Fehn for his invention of a “Motorcycle for slow cross-country travel over obstructions and in mountainous regions, and over snow and soft ground”. Further development lead to a patent that was granted in 1963, by which time the bikes were in production.
During this time, Fehn has improved the over-ride clutch design and incorporated it into the original patent. The early mechanism used a complex ball-bearing-on-ramp system, which was simplified in 1962 to a one-way spring-on-collar device, which is basically the same over-ride spring assembly still in production today. This one-way clutch allows the front wheel to travel faster than the back wheel, but not vice-versa, which means you can turn corners without the bike being driven to the ground,.
Another of the patented ideas was for a hollow aluminium wheel, each of which holds 4.5 gallons of liquid ballast or fuel. With the wheels empty, the bike can be floated on water.
Production began in 1962 with the Series 1 using a go-kart engine.. The first commercial version, the Mk0, came out in 1962, soon followed by the MK1 with another kart engine, the 98cc JLO LK101L.
The MK2 from 1963-1964 increased the engine size to a whopping 138cc, still from a (detuned) cart, and an Albion EJ gearbox, a design from the 1920’s seen on bikes such as the Francis-Barnett in the 1930’s.. This was also a preiod of company change with the entire works being bought by Rokon.
Rokon set about improving the design and reliability, releasing the Mk 3 in 1966 that would endure in to the 1970’s. One of those improvements was the inclusion of a disc brake on the front, linked to the rear wheel, and the first to appear on a production motorcycle. (That should win you a fiver down the pub.)
The Trail-Blazer continued development in the 1970’s with the Mk4 (12" wheels) and RT-140.
The range had a significant overhaul in 1974 with all-new models. Now known as Mototractors the line-up consisted of the Ranger, Scout and Pioneer and featured a new transmission; a large three-range gearbox, which combined the rear miterbox and transmission into one unit. The gears could no longer capable of shifting on the fly, instead the range was selected while the bike was at a standstill via a ‘plunger’ type shifter.
The Pioneer was soon discontinued but the Ranger and Scout would remain basically unchanged for the next 25 years.
Over the years Nethercutt and Rokon used a number of different engines. The early Nethercutt pre-production and MK1 used a 2-stroke JLO. Different model numbers of the 2-stroke West Bend 820 were used from 1962-1998. A 4-stroke Honda was available from 1994-2012. Kohler engines have been available from 1999-2010 (CS6) and 2010-present (CH270).
