Competition Etc

COMPETITION ETC

PROFILE OF A TRIALS PROTOTYPE

MIKE OBERMEYER

Bob Nickelsen’s Honda TL250 prototype is probably the most exotic trials machine working in America today. Although based on Honda’s popular X250 our-cycle enduro engine, the TL250 engine has been extensively reworked with magnesium and titanium goodies, narrowing, fin size reduction, and all the other tricks you would expect from Honda. All-up weight is 210 pounds wet.

Chassis geometry feels very similar to that on older Bultaco Sherpa T models, precise yet predictable. Super-quick steering has not been incorporated, perhaps because the machine is somewhat topheavy, in comparison to two-strokes.

The engine is so torquey that a “dump chamber” had to be placed in the exhaust system to take the edge off bottom-end power. Traction is now excellent, with a smooth torque curve, and high revs available for flexibility.

Front forks are a modification of CR125 units and are the equivalent of

t,y Spanish fork in operation, as are the ar shocks, about which neither Honda nor Nickelsen are talking.

Electronic ignition lives under an easy-access left side cover, and the throttle is a progressive unit with a ramped drum. A nicely formed alloy skid plate protects the cases, and a skyway spark arrestor/muffler caps the exhaust. The engine sounds more like other modern Honda high revving singles than the revered thumpers of bygone days. A sturdy chain tensioner is fitted.

On the bike’s second outing, Nickelsen and young George Smith finished 2nd and 3rd behind Lane Leavitt at a recent P.I.T.S. trial near San Francisco. On Nick’s return to Colorado, he promptly started winning every trial he rode.

The most striking thing about the ^fcachine is its orthodoxy—no cantilevered monoshock frame, no radical frame geometry, just proven design and exotic

metallurgy. Detailing is thoughtful, and the engine is very torquey and willing to rev, but no quantum leaps.

The production machine will be slightly heavier, perhaps around 230 pounds wet, and Nickelsen plans to switch to a. production model, as soon as they are available. “Maybe Honda will give me a few trick parts in exchange for my development work,” says Nick with a grin.

He seems more than willing, however, to sacrifice some weight against his two-stroke competitors in exchange for the outstanding torque and flexibility of the new Honda. If Ariel had stayed in business, and had had access to the geniuses from Honda R.&D. this might well be their current model. But leave it to the Japanese, after a ten year two-stroke interregnum, to produce the modern trials four-stroke. KI