Trick Parts

Pulling back the curtain on exclusive, exotic parts.

Kevin Cameron has been writing about motorcycles for nearly 50 years, first for Cycle magazine and, since 1992, for Cycle World.Robert Martin

At the races, trick stuff isn’t something that a trackside magician pulls out of his hat; it’s the equipment on factory bikes that you can’t have. Walking pit lane at Daytona in 1976, anyone with the right pass could look at the works Yamaha 0W31s, ready for practice on their stands just over the wall. We could see that, instead of the normal dollar-a-millimeter VM34 aluminum carburetors we had on our proletarian stockers, they were equipped with strange fuzzy-brown-finish magnesium carbs with powerjets. Who knows what dizzy heights of performance we proles could achieve, if only…?

An example of today’s trick stuff: Gianluigi Dall’Igna’s factory Ducatis were first wheeled out with strange scooplike multiple airfoil arrays between the back tire and the aft end of the fairing’s bellypan. What is that? And even before this trickery, when winglet arrays first appeared at either side of fairing noses, clearly oriented to produce downforce.

Detective Chief Investigator of trick stuff is Englishman Neil Spalding, who patiently patrols the pit lane at MotoGP events, knowing that sooner or later there will be an unguarded moment when a fairing is off and new, never-before-seen details can be photographed. Once, in the Valencia press room, he showed me what was possible with high resolution; he zoomed in on a photo of a factory bike’s ECU until we could read its model and serial numbers.

During the 1980s people oohed and aahed over bright titanium fasteners on factory bikes or stared with helpless longing at mag case covers retained by aluminum screws. During the ’90s I was casually handed a carbon tank from a rotary-valve Aprilia 250. It was like a paper box full of air.

Better or Not?

Trick doesn’t necessarily mean better. As I stood there in 1967, staring at the trick M-type 30mm carbs on a Yamaha importer team’s TD1-C, Jimmy Varnes, the man preparing the bike, looked up and said, “You’re probably better off with what you have. These things are a real pain to get jetted right.” The carbs on my B-model were 27mm zinc die-castings whose design originated in 1940.

Years later I would find out what happens to secret trick stuff that doesn’t work. Resting among the fast-food wrappers in a dumpster outside Yamaha’s Amsterdam HQ and workshop were a cluster of carburetors that none of us had ever seen before—all magnesium. I wasn’t proud; I climbed right in and retrieved them. Although I subsequently lent the pair of nearly complete carbs to the late Phil Schilling, I still have a papery-feeling mag float bowl to remind me. They didn’t work, so they were thrown away.

In American Honda’s former premises at 100 West Alondra Boulevard, I once saw a stack of very tool-room-looking experimental leading-link MX forks leaning against a wall. To my knowledge, those front ends never saw the sunlight.

An Ignoble End

If trick stuff doesn’t work, but is believed to contain useful information, a call is made to a “destructionator.” Big fellows arrive in a truck and get out to smash unwanted gear into scrap with sledges. The tale is told that when Honda originally took up F1 racing, the US side ordered sets of all available cast mag wheels for study. Once the study was complete, fifty-odd wheels were surplus and their destruction was ordered.

According to pre-1971 legend, when space occupied by prototype or race bikes at MV’s Cascina Costa HQ needed to be cleared, Count Agusta would personally look on as bulldozers scooped out a long trench on private land. The unwanted bikes were rolled into the trench and laid on their sides, and the dozers ran back and forth over them. Then the trench was refilled.

Also of legend is the tale that when Suzuki was building new production facilities some years ago, obsolete but still full-of-secrets classic racebikes of the 1960s went into the forms before the concrete was poured.

Who knows what dizzy heights of performance we proles could achieve, if only…?

During the ’80s and ’90s, finer gradations of trickness appeared in the form of “A-kits” and “B-kits.” While the variable exhaust ports on Rich Schlachter’s stock 1981 TZ250H Yamaha roadracer were operated by a mechanical Watt governor (invented in 1787), Martin Wimmer’s semi-factory version of the same bike drove its Power Valves by computer and stepper motor.

I was shown a pair of “FIM kit” cylinders for an early ’90s TZ250. What was trick about them? The recommended mods described on the limited-circulation tuning sheet were already built into these cylinders when cast. All the transfer windows had square corners rather than the easier-to-cast rounded corners of the over-the-counter cylinders. All the dividers between ports were of minimum width, maximizing port area. Nice parts.

MotoGP is awash with trick parts.KTM

“Trick” will always exist because it would be foolish to build more than a very few prototype parts for a development program—just enough for testing. Once superior performance has been achieved, the successful parts can be produced in whatever quantity required.

Who’s the Trickiest of Them All?

Trickest of the trick are tires, made all the more mysterious by their enigmatic nature. They offer us nothing to look at; tires are just round and black. Today the idea of spec tires—everyone gets the same—dominates high-level racing. But in the years before that there were individuals who were sure their riders could win if only they could get the same tires as Miguel DuHamel or Valentino Rossi.

Special tires certainly were made for special circumstances, one of which is the more vigorous riding of top racers. We all know that tires can’t grip properly until they reach operating temperature, and that they also lose grip if they become too hot. This is why qualifying tires are good for just one really fast lap (and sometimes not even that!) because they quickly “overtemperature” and lose their grip. It has always been the case that the general-issue tire might be too soft for the really fast riders, so slightly harder tires have on occasion been made especially for them.

Technicians from at least three different tire manufacturers have described being pestered by also-rans for a set of such trick tires. When at long last a set was provided, the predictable result was that the less-talented rider went slower on the trick tires because his riding was insufficient to bring them to operating temperature.

Sometimes the trick stuff is too trick, even for professionals. When former Yamaha US racing manager Ken Clark took me into the race team’s parts room and showed me a set of special seven-port cylinders for the TZ750 (stockers had five transfers), he remarked that hardly anyone ran the seven-ports because they were too abrupt. Then I remembered Kenny Roberts telling me why he disliked the 750.

“It just had too much of everything.”

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