Great White Hope
GREAT WHITE HOPE
KTM and White Bros. team up to turn left
REPUTATIONS ARE HARDearned, harder to amend. Never mind that White Bros, is best-known as a supplier street and motocross accessories: Brothers Dan and Tom White were once card-carrying Expert dirt trackers, and the bike on th pages is proof that their enthusiasm continues unabated.
How did these mail-order come to build a dirt-tracker? back in 1989. KTM had some of its 1988-spec 553cc four-stroke Singles stashed in a U.S. warehouse, remnants of a mass motor swap forced by incorrect kick-start ratios which rendered the Thumpers almost impossible to start. The '88 chassis were fitted with ’89 motors and sold, but the year-old engines were left orphans. Who’d buy an engine they couldn’t kick over?
The solution was obvious, if not simple: Sell the engines to dirt-track racers who push-start their bikes. And because the Whites were having some success racing a stockish KTM 600 in TTs at the time, the Austrian manufacturer approached them with the idea of building a forreal dirt-tracker.
White Bros. R&D man Kane was given the assignment, his first order of business being to ship an engine to C&J Frames, where a chrome-moly chassis was constructed around it. To this, Kane fitted Kosman triple clamps, an SPF Designs aluminum swingarm, White Power suspension, 19-inch wire-spoke wheels, Honda CR brakes and Goodyear tires.
SPF also built the fuel tank, which was done up in an outlandish pink-and-white. As Dan White
ICH CHENET
says, “We wanted to paint it a color that, whether you liked it or not, you saw it.”
Engine upgrades came next. The bore was enlarged to 100mm for a displacement of 612cc, and an Arias piston upped compression to 12.5:1. Larger, 37.5mm Manley stainless-steel intake valves were paired with the stock 30mm exhaust valves, and kept in their seats by R&D heavy-duty valve springs. Web-Cam hard-welded and reground the stock cam, and Nigel Patrick machined an adjustable sprocket to expedite cam-timing changes. Moose Racing added 11 ounces to the stock flywheel for improved tractability, and a latermodel KTM mechanical waterpump replaced the inadequate stock electric unit.
Carburetion is innovative: A 38mm Mikuni Pro Series flat-slide was coated with Marine-Tex (a type of heavy-duty Bondo) and bored out to 43mm, so that the inside diameter is now larger than the previous outside diameter.
Compared to the popular Rotax dirt-track motor as massaged by Ron Wood, the KTM’s main advantage is its liquid-cooling, which should theoretically allow it to produce peak power longer. The KTM mill also weighs less than the Rotax (73 pounds vs. 93), but that advantage is somewhat offset by the weight of twin radiators, hoses and coolant. Although the motor has not yet been dynoed. White Bros, guesstimates 60-plus horsepower. The best Rotaxes make 70.
To give the KTM tracker a shakedown, we enlisted a Wood-Rotax owner of some repute, 18-year-old Texan Mike Hale. Racing since age 6, young Mike won so often that he disassembled his trophies and sold the parts to his grandfather's scrapmetal yard for pocket money, went on to become 1989 AMA Junior National Champion and was just named 1990 AMA Rookie of the Year. We met Hale and his father/ tuner Bob at California’s Glen Helen OHV Park, where we had the use of an eighth-mile speedway
oval, plus an ATV track which was groomed into a makeshift TT.
However, we never got to turn right. After just 20-odd laps on the short track, the bike sputtered to a halt with a broken intake valve.
But all was not lost. As a rule, dirt-track practice sessions are brief, and the Hales are accustomed to short-order tuning. The duo was impressive, Mike doing a few laps and then stopping to let Bob make chassis adjustments, with but a few words spoken between them. At first, Mike was broadsliding wildly, yet following changes to the rearspring preload and damping, he was able to exit the corners more upright, getting an excellent drive and looking impressively fast . . . until the motor packed up.
Regardless. Hale found the White Bros. KTM 600 comparable to other dirt-track machines he’s ridden. “It slid a lot at first, kinda like it wanted to high-side. But (af1 ter suspension changes) it turned
out to be a lot more forgiving than I thought.” His father also had kind words: “They (the White Bros.) are at the stage where anybody would be when you first build a bike. What they brought us today wasn’t a racebike, but it’s pretty close.”
The 200 KTM engines have since been shipped back to Europe, but White Bros, plan to continue with the project. They’re presently soliciting resumes in the hopes of finding a rider/tuner combination that can put the bike on the flat-track map in 1991.
“We don't have any delusions of blowing off Ron Wood or Bill Werner,” Dan White says. “We just feel that we can build a bike that will become competitive in a relatively short period of time. We hope that by bringing KTM into the game, it will convince other manufacturers to become involved.”
And, just maybe, it will help the White Bros, build a whole new reputation. —Brian Catterson
