The world’s fastest 500 single
Five wins at Bathurst from 1966 made Ron Toombs and the Henderson Matchless the most successful combination in Australian racing. That machine comprised a 1962 2-valve Matchless G50 engine in a highly modified Norton frame, with just about everything else hand-made by Sydney engineer Tony Henderson. But by 1970, even Toombs’ talent in the saddle and Henderson’s demon tweaks were not enough to keep the machine competitive against the growing Yamaha presence, and Henderson decided to create a new machine virtually from scratch.
The engine was still based on the traditional Matchless G50, but incorporated a four-valve head machined from solid by Henderson. The piston was also machined from solid aluminium. From the start, the 4-valve engine revved to 9,200 but paid the price in terms of reliability. “I straightened the titanium con-rod at least three times,” said Tony. “ It dropped a valve at Oran Park once and wrecked just about everything but the head itself. That took about three months’ work to get it back together again.”
A super-lightweight full cradle frame diamond was fabricated by Malcolm Sullivan and welded by Bob Brittan, who made his name building the successful Renmax racing cars – copies of early Brabhams. Henderson fabricated a box-section stainless steel swinging arm from 18-guage material and also cast his own magnesium fork sliders. Fuel and oil tanks were the work of Nuge Smith, who had made copies of the British Beasley frames (notably for Sid Willis) in the fifties. Initially an Aerheart front disc was fitted, but this was found to be inefficient, as well as making the front end far too light. Tony acquired a set of unfinished casting made by Canadian Bob Cusil for a double-sided 8-inch front stopper, machined the magnesium castings and cast iron liners, made all the cams, levers and pivots, and laced the rim. The result not only restored the weight balance to keep the front end on the ground, but stopped perfectly. A small rear disc was machined and fitted with a modified single-piston calliper from a CB500 Honda. After closely studying the flat-side Gardner item, Henderson made his own 1 3/4-inch carburettor, This proved difficult to tune until the needle diameter was increased to 5/32-inch, and after experiencing fuel feed problems the bowl was dispensed with and methanol fed directly to the metering unit.
“We were entered for the Phillip Island meeting on New Year’s Day, 1970 and I finished the (four valve) motor one morning just before then. Toombsie picked up the bike, which then fell out of his trailer on the way home! Nevertheless, the phone rang in the afternoon and it was Ron’s wife Mavis on the line. She held the phone up so I could hear the engine running in the background.”
Considering the total lack of testing, the creation worked well from the outset, the most serious problem being the primary chain, which stretched dramatically. “If you look at the chaincase, you can see the indendations from where the primary chain constantly threw off the rollers,” Tony points out today. “ We were running the same primary-size chain on the rear as well, so we ended up pre-stretching the chain on the rear before fitting it to the front”.
The adaptable Toombs, who had started racing of a pre-war AJS, was by now highly successful on the latest Yamahas, but continued to campaign the Henderson Matchless, much to the delight of the crowd, in 500cc and Unlimited races. When it lasted, it was unbeatable. Easter Bathurst in 1970 marked the last big win. The Senior TT saw Toombs pitted against the rapid but frisky new Kawasaki H1R racers, in the hands of Kenny Blake and Jack Ahearn, as well as a plethora of 350 Yamahas. Blake cleared off to a huge lead until a broken chain brought him to a halt, leaving Ron to score a memorable win for big singles over Ahearn and Kevin Cass. The Matchless was timed at over 140 mph (225 km/h) on Conrod Straight.
In its final form the bike weighed just 240 pounds (109 kg). After its last race in 1973, the engine was sent to England where grass track legend Don Godden installed it in one of his frames and rode it to victory in a long track meeting at Vilshofen in Bavaria.
Fortunately, the components of the famous bike were reunited in 1988 by Henderson and former Australian champion Tony Hatton, who demonstrated it at the inaugural Phillip Island GP in 1989. Soon after, the Henderson Matchless Mk2 was permanently loaned to the National Motor Racing Museum at Bathurst, undoubtedly its spiritual home.