1973 Yamaha TX650
Engine: 653cc SOHC air-cooled parallel twin, 75mm x 74mm bore and stroke, 8.7:1 compression ratio, 53hp @ 7,000rpm (claimed)
Top Speed: 105 mph (period test)
Carburetion: Two 30mm Mikuni CV
Transmission: 5-speed, chain final drive
Electrics: 12v, coil and breaker points ignition
Frame/wheelbase: Dual-downtube steel cradle/56.1in (1,425mm)
Suspension: 35mm telescopic forks front, dual shock w/adjustable preload rear
Brakes: Single 11.7in (297mm) disc front, 7.9in (201mm) SLS drum rear
Tires: 3.5 x 19in front, 4 x 18in rear
Weight (dry): 420lb (191kg)
Seat height: 30.5in (775mm)
Fuel capacity: 3.3gal (12.5ltr)
Price then/now: $1,419 (1973)/$2,500-$6,000
This 1973 Yamaha TX650 isn’t a motorcycle. While it might look like one, in reality it’s a fully functioning time machine. That’s because owner Keith Allen is connected to this particular motorcycle in ways most of us could only imagine.
“In the early summer of 1973 I was 16 years old,” Keith explains. “I’d been riding and racing dirt bikes, and my dad and I went to the Honda, Harley-Davidson and Yamaha shop Zanotti Motors in Butler, Pennsylvania, because he wanted to get a 2-stroke Yamaha RD350 street bike.
“When we got into the dealership there were five TX650s lined up in the window, and I steered him towards the larger 4-stroke motorcycles. He wrote a check for this one and tossed me the keys, telling me to ride it home.”
Keith had only just received his driver’s license, and the road home was a major four-lane highway. Back in 1973, the Yamaha 650 was considered a big motorcycle, and Keith was slightly nervous. “Once I got on it I wasn’t stopping, and the nervousness disappeared after a mile,” he says, chuckling at the memory.
First the XS-1
In 1970, Yamaha introduced the 650cc XS-1 parallel twin. The XS-1 took much of its inspiration from British models, especially the Triumph Bonneville. Yet where the Bonneville was the product of a now dated design originating in 1937 with the Speed Twin, the XS-1 fairly bristled with all the latest technology Yamaha could throw at it. That included an overhead camshaft, twin constant-velocity carburetors, horizontally split crankcases and a 5-speed transmission.
Getting there wasn’t easy, however. “The development program was long and torturous, with many false steps and redesigns needed,” writes Colin MacKellar of the XS-1 in Yamaha Street Bikes 1955-2009. “Numerous prototypes were built and rejected, leading in total to a file containing 2,500 pages reflecting design modifications undertaken during the project.”
At last, the final XS-1 prototype was unveiled in October 1969 at the Tokyo Motorcycle Show. MacKellar notes that both the industry and the public alike took interest in the first 4-stroke production motorcycle debuted by Yamaha, a company known at that time for its reliable — and fast — 2-stroke machines.
Industry response to the new bike was good. Cycle World editors in March 1970 said, “In its introductory year, the XS-650 must be considered a succes fou (crazy success), having supplied all the ingredients required to please the Big Twin fancier in an up-to-date, beautifully styled package. It looks good, rides good, stays clean and shows few of the faults one would expect in a first year model.”
Yamaha’s new 4-stroke twin-cylinder engine featured a slightly over square 75mm x 74mm bore and stroke, and fired alternately on its 360-degree crankshaft supported on four main bearings. Four separate lightweight flywheels made for an engine that was happy to respond to a blip of the throttle, and the gears were prodded into place with a left-side foot lever.
Bearings on the timing side and two center mains were roller-style; the drive side was a ball bearing. Inside the alloy cylinder barrel with iron liners traveled aluminum pistons and a cast-in cavity housed the cam chain. The cylinder head was also alloy, and to reduce noise Yamaha located small, white, rubber discs alternately between the fins.
Straight-cut gears transferred power from the crankshaft to a corresponding gear on the clutch, and the transmission gears shared engine oil inside the crankcase. The engine was solidly mounted in a dual-downtube steel frame with a single backbone and a tubular swingarm for rear suspension. Up front the forks featured steel lower sliders, and drum brakes were at both ends.
Yamaha continued the XS line, which many magazine testers of the day criticized for suspect handling, with the XS-1B of 1971, and further updated the model in 1972 with the XS-2. New for the XS-2 were a front disc brake, alloy lower sliders for the forks and an electric starter.
From XS to TX
It’s here that the model nomenclature can get confusing. By 1973, Yamaha had introduced their TX750 twin and its smaller brother, the TX500 twin. Although the machines were all different, to bring the 650 into the range, Yamaha changed the prefix from XS to TX, resulting in the 1973 TX650. It was a change in name only: There was little difference between the 1972 XS-2 and the 1973 TX650.
The 1974 TX650A was significantly updated, however, as Triumph test rider Percy Tait had been enlisted to help improve the handling of the 650 model. He suggested extending the headstock and swingarm, moving the engine forward and down, and adding gusseting around the headstock and engine mounting plates for improved rigidity.
Unfortunately, neither the TX500 nor the TX750 were successful sellers, the TX750 in particular plagued by serious reliability issues. For 1975 Yamaha dropped the TX750 and the TX prefix, the 500 becoming the XS500 and the 650 the XS650B. The XS500 was dropped in 1978, but the XS650 carried on until 1983 in the “Special” models before it was dropped from the U.S. market, although it was offered in Canada and Europe until 1985.
Way back when
When the Allen family bought its new-for-1973 TX650, they already had two other Yamahas, a CT175 and an RT360. The machines were all treated as recreational vehicles, and Keith and his older brother Bruce were allowed to ride any one of them any time, except on weekends: That’s when Keith’s dad, Robert, and mom, Mae, took long rides aboard the TX650.
Sadly, in 1974 Robert was diagnosed with terminal cancer, and really only got to enjoy the bike for a single year. At that point, Keith began riding the TX to high school, and then for his first two years of college. He and his brother, Bruce, shared the TX, but Bruce took it over full time in 1978 and finally parked it in 1983. Unfortunately, Bruce died in 1990, and Keith took over the TX again, using it sparingly for two years in the mid-1990s before parking it in his mom’s garage in 1996. It didn’t come back out again until 2014, when Keith decided the TX deserved to be completely restored.
“It was in decent shape,” Keith allows, adding, “but the alloy of the engine cases and on the forks was pitted from age and everything just looked tired. I wanted it to look like it did when we rolled it out of Zanotti’s in 1973.”
That’s when Keith called Brady Ingelse of Retrospeed in Belgium, Wisconsin. Keith knew exactly what he wanted, and Brady says a contract was drawn up that included a set price and a definite timeline from start to finish. The TX was dropped off in late September 2014, and rolled back into Keith’s garage a little less than a year later, in late July 2015.
“Apart from the fairly obvious restoration of the motorcycle,” Brady explains, “Keith had a few complaints about the TX that we set out to fix for him. The first issue was the bike would put oil to the ground, and not through the conventional areas a bike would leak.” After doing some research, Brady learned early XS and TX650s had problems with the breather system, resulting in the occasional oil drip. Yamaha had two solutions: First, lower the oil level in the crankcase and file a new “upper” level line on the dipstick; and second, update the internal baffle plate with one from a later XS. Brady did both, but after careful reassembly and after the first ride, “It put oil to the ground,” he says. “It was a quarter-sized spot, but Yamaha’s fixes didn’t help.”
To stop the oil drip, the Retrospeed crew installed a vented breather catch can, or in this case, a box, and tucked it up under the front swingarm pivot. It’s impossible to see without physically getting under the TX650, and the box has a drain to allow removal of any excess lubricant.
“We ride XS and TX Yamahas a lot,” Brady adds, “and they vibrate and shake quite a bit. To quell some of the vibrations, Yamaha rubber-mounted everything except the engine. When you replace every piece of rubber, it’s amazing how smooth they can feel. It’s night and day the difference in how the Yamaha twin feels. They really help quell the vibrations. There’s over $300 in new rubber trinkets, and that’s enough pieces to fill an ice cream pail.”
To rectify a few other quirks that Keith wanted fixed, Brady added tapered roller bearings to the steering head, updated the swingarm bushings, replaced the rear shocks and changed the fork springs. A hidden electronic ignition makes the TX650 easier and happier to start, and Retrospeed also paid some attention to the electric starter, which liked to growl and clunk when it was engaged. “We used a later Yamaha starter fork, and that puts a little more drag on the starter gear to help quiet things down,” Brady says.
All the bike’s black components, including the frame and brackets, were powder coated, and Jason Jacoby of Jacoby’s Autobody in Cedar Grove, Wisconsin, applied the metallic blue paint, with numerous test sprays made to ensure the blue was an exact match to original. Cody Meetz of Custom Plating Specialists in Brillion, Wisconsin, brought the luster back to the plated metal parts. Keith opted to leave the gauge faces and the 25,629 miles showing on the odometer alone, but the bezels were treated to fresh chrome.
Brady acquired many pieces needed for the TX650 restoration from family-run Port Yamaha in Port Washington, Wisconsin. The shop tracked down parts it didn’t have, and also stocks an inventory of older pieces. “It was a beautiful motorcycle that didn’t give us a ton of static during the restoration process,” Brady says. “It was fairly straightforward, with just a couple of challenges along the way.”
Keith has four other motorcycles right now, including a Honda Gold Wing 1800 and a Harley-Davidson XR1200. He’s extremely happy with how the TX650 turned out, and now rides it occasionally, often adding 100 miles per jaunt. He loves the engine, saying it makes a delightful, throaty sound, and he likes how the Yamaha builds speed in a nice, linear fashion.
“For me, it’s all about nostalgia,” Keith says of his family’s old, but entirely refreshed Yamaha TX650. “When I’m on it I have a connection to times when the family was all together. My dad rode it, my brother rode it, and I feel connected to them through the Yamaha. I’m just reliving bits of my youth.” MC