
Here, Eddie Mateer gives an insight into the background of the story.
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In 1977 the genius of Terry Shepherd continued with racing motorcycles when he built a futuristic alloy frame to house the TZ engine.
It had a hollow backbone chassis which held fuel as well as supporting the TZ engine. On top of that sat the extraordinary tank with inset panels to provide streamlining for the arms.
He built approximately 22 of these alloy frames, the majority of which went to the USA in 1978.
Tom Herron was in contact with Terry and, after a trial run on the continent, Tom agreed to ride the bike at the British GP in 1977.
But after setting the fastest time in the first two practices, he had to revert to a 'normal' TZ as his sponsor wanted him to race his 250.
The next time Tom rode the Shepherd was at the Ulster Grand Prix. In a hectic last lap, Tom and Alan North crossed the finish line in a dead heat but the verdict was given to Tom.
The next and final time Tom was seen on the Shepherd was in national road races in Germany and Austria.
I know because Tom lived only a few hundred yards from where I live in Lisburn, and after buying this particular bike from a chap by the name of Andrew Harrison, who lived in Cumbria and who knew Terry Shepherd.
I have since sold the bike.
In 1978, Terry built a couple more for Tom but instead of using alloy, he cast the frame, wheels and swing-arm in magnesium to make the entire machine lighter.
The wheels were his own special design and the engine was supported by an 'A' frame.
At the time Tom was very friendly with Harald Bartol and spent time with him in Austria.
Bartol designed a disc-valve engine based on the TZ engine which Tom had installed in the Shepherd magnesium frame.
Tom agreed to race these bikes in the GP races. Terry Shepherd went one better when he designed and cast TSR (Terry Shepherd Racing) barrels and heads (250) to be used.
As this engine was in its development stage at the beginning of 1978, Tom's GP qualifying times were poor and after two early races Tom dumped the project and bought two TZ 'E' Yamahas.