A Handbuilt Yamaha Trackmaster TZ750 Dirt Tracker With 120+HP

This Yamaha Trackmaster TZ750 dirt tracker was built by AMA Hall of Fame Member Gary Davis, a former professional motorcycle jumper, veteran Hollywood stuntman, motorcycle racer, and master fabricator.

The TZ750 is best known in dirt track circles for the win by “King” Kenny Roberts at the 1975 Indianapolis Mile over the formerly dominant Harley-Davidson XR750s. It was this victory that caused the AMA to promptly ban the TZ750 from flat track competition from that moment on.

The Yamaha TZ750

• There can be no denying that the Yamaha TZ750 is one of the most important and influential motorcycles of the 1970s. Legendary motorcycle writer Kevin Cameron even included it on his list of the five greatest motorcycles of all time.
• The secret to the success of the TZ750 was its remarkable inline-four cylinder two stroke engine which was said to be capable of well over 120 bhp – a staggering power figure for the era.
• The biggest challenge Yamaha engineers faced was building a frame, suspension, and braking system that could cope with the power – early examples of the bike were famous for being widowmakers.
• American motorcycle chassis specialists Trackmaster were able to tame the TZ750 engine by fitting it to their own frame matched with flat track suspension, creating a motorcycle that was exceedingly fast for those riders who could master it.

Yamaha’s Mighty Widowmaker

The Yamaha TZ750 was called “the most notorious and successful roadracing motorcycle of the 1970s” by Motorcyclist Magazine, though that may sound like hyperbole the evidence is on their side.

Early examples of the TZ750 became famous for being widowmakers, the flexible frames, insufficient brakes, and poor suspension were no match for the 120+ bhp bring produced by the engines – even the tires would shred themselves down to the canvas when used in anger.

When Yamaha released the TZ750 in 1974 it made their fellow Japanese motorcycle manufacturers sit up and take notice. What Yamaha had essentially done was take two of their parallel twin TZ350 two-stroke engines and join them at the hip – creating an inline-four with an original displacement of 694cc and 90 hp.

Over the following years the TZ750 would be developed rapidly, by 1975 the displacement was up to 747cc and engine tuning had brought the power up to over 120 bhp. Modifications would be made to the frame, suspension, and brakes to continually improve the motorcycle’s performance.

The Yamaha TZ750 would win the Daytona 200 nine times consecutively from 1974 onwards, it would also win the 1980 Isle of Man Classic TT with Joey Dunlop at the helm, setting a new average speed record of 115.22 mph (185.43 km/h).

The TZ750 would take a slew of wins in other races in the United States, Europe, and around the world. It was an almost unbeatable motorcycle in its day and surviving examples are now highly sought after by collectors.

The Yamaha Trackmaster TZ750 Shown Here

The Trackmaster-framed TZ750 you see here was built by none other than Gary Davis, a former race-winning professional motorcycle racer and a retired motorcycle daredevil that took records from Evel Knievel back in the 1970s.

Davis became a Hollywood stunt rider by the late 1970s, he’s now worked on over 280 films, more than 250 TV episodes, and 190 plus commercials. His film credits include “X-Men: Days of Future Past,” “The Amazing Spiderman,” “Against All Odds,” “Terminator 2,” “Independence Day,” and “Spiderman 2.”

This bike was built around a Trackmaster frame with a worked Yamaha TZ750 engine fitted with Mikuni flat-slide carburetors, V-Force reed assemblies, and four hand-fabricated, custom-tuned expansion chambers.

The bike is now due to sell at the Las Vegas Motorcycle Auction which will be held by Mecum in late January. If you’d like to read more about the bike or register to bid you can click here to visit the listing.

Images courtesy of Mecum