Harley-Davidson Tx-125

HARLEY-DAVIDSON TX-125

Practicality Usually Takes A Back Seat To Performance . . . But Not Always

Cycle World Road Test

THE Harley-Davidson/Aermacchi 125 Rapido model, first introduced into this country in 1968, made a lot of friends with the road riding commuter set. A 125 clearly isn’t the hot tip for freeway jaunts, but for around town use it’s a nicely sized machine.

Then came the H-D Baja model a couple of years later, which was basically a Rapido model sleeved

down from 125 to 98cc and set up for desert and scrambles racing. Of course, it couldn’t be ridden on the street in this configuration and Harley-Davidson saw the handwriting on the wall; it had to produce a combination street/trail machine to compete with the myriad of such machines being imported from Japan.

Just a fleeting glance at the TX-125 will tell you that it's a dual-purpose machine; high mounted front fender, motocross style handlebars with a cross brace and a high mounted exhaust pipe are all the earmarks such a machine needs to identify itself with this class.

An interesting feature of the TX-125 is the dual rear sprocket unit. Each TX-125 comes with an extra piece of chain so that the larger rear sprocket may be used for off-road work. Incidentally, the drive chain may be transferred to the trail sprocket without removing the rear wheel. This saves the rider time when he has to ride his TX-125 out to the woods on the street, have his off-road ride, and then ride the machine back home again.

The engine differs from earlier models in that it features an oil injection unit which makes it unnecessary to pre-mix the gas and oil. The oil tank is mounted up under the front part of the gas tank and looks like an afterthought. This high location does ensure that all the oil will flow down to the pump to be delivered to the engine, however.

The first pumps are being manufactured by Mikuni in Japan, but later models will have Italian pumps. Located on the right hand end of the crankshaft, the oil pump delivers oil to the engine in relation to engine rpm and throttle opening through a tube that runs into the intake manifold. It’s a simple and foolproof system to be sure.

The mildly tuned engine starts on the first or second kick every time and soon settles down to a smooth, even idle. Both mechanical and exhaust silence of the TX-125 really pleased us. You can hardly tell when the engine is running. Even full throttle operation produced a minimum noise level.

Economy of operation is also impressive. Very little fuel is consumed, even when run flat out on the trail sprocket. One fill-up of the 2.4-gal. tank should be sufficient for an all-day outing in the country.

One facet of the engine’s character annoyed us, however, and that was its propensity to vibrate heavily at about three-quarters of the engine’s rev limit. Below that point, which we estimated to be 6000 rpm, and above it, there was very little vibration.

The transmission proved to be a disappointment because it was difficult to shift gears and to find neutral at a stoplight. We were informed that later production models have a somewhat modified shifter plunger which eases the shifting chore considerably. In fact, any owner of an early TX-125 with shifting difficulties may have the modification to the shifter plunger performed free of charge at his Harley-Davidson dealer.

Even with the trail sprocket in place, we felt that the transmission gear ratios were a little too far apart. We’d like to see closer spacing between the ratios in spite of the engine’s wide power band.

The clutch is the strong point of the entire drive train. Even after much slipping while riding in the rough terrain at Saddleback Park, the clutch never complained or lost adjustment. If only the transmission had been easier to shift....

The original frame has been beefed up and modified for increased engine protection necessary in off-road riding. The backbone design of the main frame is still there, but two additional tubes now run downward from the steering head, loop under the crankcase, and terminate just behind the engine. A steel plate is welded between these tubes under the engine to serve as a bash plate as well as to strengthen the frame.

Steering geometry is set nicely for road riding. The machine is nimble and handles well through corners. It would probably handle better out in the rough if the front forks weren’t so stiff and if the rear suspension units had more rebound damping. Negotiating rough downhill sections produced the dreaded pogo stick feeling. Although we’ve found very few dual-purpose machines with really good rear suspension units, those fitted to the TX-125 are below average.

Braking power of the TX-125 was very good indeed. Slightly more lever pressure than we felt was necessary at the front made it difficult to slide the wheel, but the rear brake was perfect with just the right amount of feel.

Tires fitted to the TX-125 are definitely better suited to road riding than for use in the dirt. The front is a 3.00-19 Pirelli Universal road tire. The rear is a more appropriate (for a dual-purpose machine) 3.50-18 Pirelli trials universal. >

For street riders, this choice of tires is fine. Sure, the substitution of a road universal to the rear would increase rear end traction on asphalt, but with the limited power on tap, this switch isn’t really necessary.

Like we indicated earlier, the TX-125 is pleasant on surface

HARLEY-DAVIDSON

TX-125

$595

streets. It weaves through traffic with ease, is highly maneuverable at all speeds, and has enough power on tap to keep up with stop and go, rush hour traffic.

Off-road, the little Harley doesn’t fare nearly as well. For one thing, the front end washes out in turns. Changing the front rubber to a trials universal would help a lot here, but you’ll still have to put up with skitterishness at high speed caused by a high center of gravity and short wheelbase. And, you’ll have to give up sliding turns (lack of power) and climbing steep hills (lack of power and short wheelbase).

Sticking to established trails and moderate speeds is the only practical solution. Anything more off-road is simply exceeding the design capability of the machine.

Appearance of the TX-125 is first rate. Chromium plating is of high quality, wheel hubs and front fork sliders are polished aluminum and paint on the gas tank is smoothly applied. The accent stripes on the gas tank appear to be decals and a few near the gas filler cap began to peel away slightly when touched by gasoline. We would rather see these painted on.

Engine side covers and cylinder barrel are finished in a heat dissipating matt black while the cylinder head is left in its sand cast aluminum roughness to further aid engine cooling.

With the advent of the 1973 Federal Standard requiring street machines to have turn signals, Harley-Davidson went to an alternator/coil and battery ignition system to provide the extra current required for the additional electrical components.

All the electrics worked fine, with the headlight throwing a beam strong and wide enough to ride the TX-125 at its moderately high speed potential with safety. Wiring is of good quality and reasonably well protected from damage, and the horn was quite audible, although angled so that it emits its tone to the left hand side of the machine.

In general, the Harley-Davidson TX-125 is a sturdy, well thought out street/trail motorcycle. If you’re willing to trade some style for easy access to components, prefer economy to all out performance, and plan to stick to roads or established trails, the TX-125 is an appropriate choice. I§l