Triumph TR5MX: Last of the line
There’s always been a rivalry between BSA and Triumph fans – it’s a ‘local derby’ thing. Many BSA diehards wouldn’t have a Triumph as a gift, while plenty of Triumph fans believe the only good thing to come out of Birmingham is the Coventry Road.
Which makes it more than a touch ironic that the last of BSA’S B50 models should actually have been marketed as a Triumph. But with plenty of B50MX parts still kicking around the factory, it made sense to try to make something of them. And the US ‘recreational’ off-road market must have seemed like a good place to sell that something. With the popularity of the Triumph brand in dirt riding circles Stateside influencing NVT’S production strategy, the TR5MX Avenger was the result. Differences to the B50MX were minimal. There was a 21in front wheel (oddly, the B50MX had a 20in wheel) and the energy transfer ignition of the BSA was ditched in favour of a points and capacitor set-up with a greater range of advance. Improved valve springs and a bashplate were fitted, plus an alloy tank borrowed from the Adventurer twin.
Cycle magazine, already big fans of the BSAbadged B50MX they’d tested in March 1972, were similarly impressed with the Triumph-branded version in March 1974. They rated the ignition a big improvement that made starting a whole lot easier. On track, the Avenger’s low-speed pulling power came in for high praise. Handling and steering were better suited to smooth, fast trails than more choppy, rocky terrain and the brakes could have been a touch more powerful, but that was about the extent of the criticism from Cycle’s team. Tony Howard didn’t buy his TR5MX with motocross heroics in mind, though. He prefers a spirited blast round his nearby Essex back roads. He bought the bike seven years ago – but, unlike the subtly modified BSA, he decided to keep the rare Triumph in catalogue specification.
“That made the restoration harder,” he admits. “I spent two years collecting parts before making a start. I haven’t used any pattern parts on this bike – everything is genuine factory. I don’t use the internet either, so that made things harder still. But through the network of contacts I built up while restoring the BSA, I found everything I needed. The genuine tank came from a customer of Ace Classics, the silencers and rear mudguard were NOS from Vale-onslow and Chris Burrell came up with the rear mudguard. I even managed to find an original seat cover.”
With parts sourced or repaired and specialist work including the engine restoration, paint and wheel building farmed out, the build only took Tony a few months. “It’s a simple bike,” he says. “And I’ve tried to keep it that way. There are no lights, indicators or battery and it runs an Electrex World motocross ignition. I’ve stuck to the spirit of the original.” So how does a bike intended for the wide open spaces of west coast America translate to rural Essex? Rick P is the lucky man who gets to find out...
“It takes some time looking at Tony’s immaculate TR5MX to get over the discordant combination of engine and tank transfer. Triumph’s 250 is common enough, but somehow the B50 and Triumph’s TR5T Adventurer are both too iconic to be mixed. Using the subtly different Adventurer tank makes this seem more hybrid than desperate badge engineering.
“The bikes feel very different, too – partly because Tony has the TR5MX in a lower state of tune than the B50. A compression plate takes the sting out of kickstarting and there is definitely not the same urge when you open the throttle, the engine feeling more trials than motocross – but then this bike is the greater rarity. For a rider, there’s little point having two bikes identifiable only by a tank badge.
“While Tony has built the BSA to suit himself, the much rarer TR5MX is a catalogue restoration. He warned me to be cautious on bends, but I am already familiar with the ‘creep’ you experience with knobbly tyres on the road – a bit like walking on platform-soled Doc Martens. The TR5 felt as well set-up as the B50, but I was less tempted to head for the hills. There is always a dilemma with rare machines – do you enjoy it and risk spoiling it or preserve it, lifelessly in a glass case? Tony has done the clever thing. He has made it perfectly pleasant to ride, but removed the temptation to get carried away – there’s a B50 in his garage for that.