The 1970s were not only boom times for dirt biking they also signaled an era of intense technical development that was to go on through the 1980s. During this time there were profound developments in suspension, chassis and engine design that would change the face of all branches of off road motorcycle sport, while at the same time moving the disciplines further apart.
In the 1960s a rider could ride trials, and motocross and probably ride to work as well on one motorcycle, but by the 1970s specialisation in both trials and motocross machinery meant that it was getting harder to do so. Filling the gap however was a new type of dual purpose dirt bike, the trail bike. The advent of sophisticated Japanese made trail bikes coincided with the relaxation of import and hire purchase controls in NZ. In a few short years trail bike sales were booming.
At the same time specialist European enduro bikes like Husqvarna, Montesa, Bultaco and Zundap were very rare in NZ. The European brands were not well represented in NZ and tiny importers were loath to sponsor riders.
Japanese trail bikes however were available and were selling by the shipload, so that Enduros in NZ at this time were mostly ridden on modified Japanese trail bikes. The trail bike was only intended as an all round dual purpose machine, and were not suitable for enduro competition in standard form. Of course kiwi riders soon started doing what they had always done, hauling them into the shed and making them work. In most cases this amounted to changing gearing and tyres, adding rim locks, removing all surplus equipment and substituting lighter more crash resistant lights.
Many riders went further adding better quality shock absorbers and engine performance parts like larger carburetors and special exhaust pipes. When long travel suspension was invented late in 1974 many riders took on the brave job of cutting their frames to move the top shock mount forward and fit the latest gas charged shocks that were necessary to take the increased stress of longer travel.
The ultimate shed creations of the 1970s were the handcrafted amalgamations, called specials. The special could take on many guises. The most popular was to fit a trail bike engine into a motocross chassis. At this time motocross chassis were usually built from better materials, were lighter, with better suspension components and so were stronger and better handling. Motocross engines of the day however typically had very narrow power spreads, light flywheels, close-spaced gear ratios and small fuel tanks. This made them unsuitable for the enduro courses of the 70s. These were single lap all-day rides with steep off road terrain and long road transport sections.
Another popular special theme was to modify a trials bike for enduros, a fairly easy job because at that time trials, enduro and MX bikes all had the same minimal amount of suspension travel and trials bikes all came road capable and with a fairly high top gear for road use. At the simplest modifications would involve a larger seat base with added foam and fitting knobbly tyres, but it did go further with longer travel rear suspension and engine modifications for more top end power.
The final solution was to take a motocross bike and make it more suitable for enduro riding. This could be done by changing the light MX flywheel for an enduro one, or adding a flywheel weight and even switching to a more torquey enduro cylinder and exhaust. Registering an MX bike for road use was no drama in the 70s once basic lights and muffling were fitted.
The days of competing on trail bikes was put to rest in the late seventies by the development of specialist enduro race bikes. The building of specials also tailed off but a few were still built into the late 1980s by which time motorcross and enduro bikes had moved so close together as to make the job almost pointless. The last really effective special was probably Shaun Stanbridge's highly successful NZ Champs class winning Kawasaki KX125 chassis with KDX 200 C3 engine.
In the 1960s a rider could ride trials, and motocross and probably ride to work as well on one motorcycle, but by the 1970s specialisation in both trials and motocross machinery meant that it was getting harder to do so. Filling the gap however was a new type of dual purpose dirt bike, the trail bike. The advent of sophisticated Japanese made trail bikes coincided with the relaxation of import and hire purchase controls in NZ. In a few short years trail bike sales were booming.
At the same time specialist European enduro bikes like Husqvarna, Montesa, Bultaco and Zundap were very rare in NZ. The European brands were not well represented in NZ and tiny importers were loath to sponsor riders.
Japanese trail bikes however were available and were selling by the shipload, so that Enduros in NZ at this time were mostly ridden on modified Japanese trail bikes. The trail bike was only intended as an all round dual purpose machine, and were not suitable for enduro competition in standard form. Of course kiwi riders soon started doing what they had always done, hauling them into the shed and making them work. In most cases this amounted to changing gearing and tyres, adding rim locks, removing all surplus equipment and substituting lighter more crash resistant lights.
Many riders went further adding better quality shock absorbers and engine performance parts like larger carburetors and special exhaust pipes. When long travel suspension was invented late in 1974 many riders took on the brave job of cutting their frames to move the top shock mount forward and fit the latest gas charged shocks that were necessary to take the increased stress of longer travel.
The ultimate shed creations of the 1970s were the handcrafted amalgamations, called specials. The special could take on many guises. The most popular was to fit a trail bike engine into a motocross chassis. At this time motocross chassis were usually built from better materials, were lighter, with better suspension components and so were stronger and better handling. Motocross engines of the day however typically had very narrow power spreads, light flywheels, close-spaced gear ratios and small fuel tanks. This made them unsuitable for the enduro courses of the 70s. These were single lap all-day rides with steep off road terrain and long road transport sections.
Another popular special theme was to modify a trials bike for enduros, a fairly easy job because at that time trials, enduro and MX bikes all had the same minimal amount of suspension travel and trials bikes all came road capable and with a fairly high top gear for road use. At the simplest modifications would involve a larger seat base with added foam and fitting knobbly tyres, but it did go further with longer travel rear suspension and engine modifications for more top end power.
The final solution was to take a motocross bike and make it more suitable for enduro riding. This could be done by changing the light MX flywheel for an enduro one, or adding a flywheel weight and even switching to a more torquey enduro cylinder and exhaust. Registering an MX bike for road use was no drama in the 70s once basic lights and muffling were fitted.
The days of competing on trail bikes was put to rest in the late seventies by the development of specialist enduro race bikes. The building of specials also tailed off but a few were still built into the late 1980s by which time motorcross and enduro bikes had moved so close together as to make the job almost pointless. The last really effective special was probably Shaun Stanbridge's highly successful NZ Champs class winning Kawasaki KX125 chassis with KDX 200 C3 engine.