BUELL STREET TRACKER ‘HARDLY-DAVIDSON’
Until the 1970s motorcycle racing in the USA was all about dirt track. On mile and half-mile ovals across America Triumphs, BSAs and Nortons competed against the homegrown Harleys. Despite it’s agricultural persona, dirt track racing, (also known as flat track), is a very precise form of motorcycle competition with the machinery having evolved over many years into the ideal weapon needed to cover a mile, or half-mile oval racetrack with a loose surface of clay, sand or dirt in the shortest possible time. The ability to control a bucking weaving motorcycle at speeds approaching 130 miles-per-hour, slipping sideways into a corner while ‘steering’ the rear wheel with the throttle, is an art learned on the dirt tracks that made American racers like Kenny Roberts, Eddie Lawson and Wayne Rainey into World Roadracing champions.
Following the AMA rule change in 1968 that finally allowed 750cc OHV machines to compete with the 45 cubic inch, (750cc), Harley-Davidson sidevalve KR750s, British twins began to dominate dirt track racing in America. Hoping to capitalise on the AMA change in capacity regulations, Harley-Davidson downsized their OHV 883cc Sportster ‘900’ to 750cc for the 1970 season. But despite winning its debut race on the dirt the first generation XR750s would always prove troublesome and unreliable due to the fact that it was a roadster-based engine with heads and cylinders made out of the same heavy and heat-retaining material as a cast iron stove. A fact hammered home when the factory roadrace ironhead XR750s were massacred at Daytona in 1970 when all four bikes blew their engines trying to run with the latest 750cc roadster-based multi-cylinder bikes from Europe and Japan. While the second generation all-alloy XR750, (produced from 1972), never shone in world class road racing, the XR did, however, totally obliterate the opposition on the dirt tracks throughout the Seventies. And, apart from a couple of exceptions, (like Kenny Roberts on a Yamaha in 1973 and ‘74, and the factory Hondas of Bubba Shobert, 1984-87, and Ricky Graham in 1993), the Harley-Davidson XR750 remains a dirt track championship winner right up to the present day.
This Buell engined street legal flat tracker was built by Bill Gately when he lived in California before moving to Florida and establishing Bonneville Performance, the premier tuning company that develops and produces tuning parts for the latest Hinckley Bonnevilles and races the same Triumph twins in the Grand National Dirt Track Series. Bill wanted a nimble and powerful bike to go canyon racing on the twisty roads in mountains of Southern California and decided to build a street legal ‘XR750’ using a Buell engine and a Champion dirt track frame. Genuine Harley-Davidson XR750 engines are both expensive and unsuitable for a street bike due to their lack of a charging system and need for regular rebuilds. A pretty good substitute for an XR750 engine, (in a streetbike), is the tuned Sportster 1200 motor used by Buell in their pre-XB sport bikes. And Bill knew where there was just such an engine that would fit in a Champion frame and, (with some additional tuning), would easily outperform an XR750 race engine.
Bartels’ Harley-Davidson in Culver City, Los Angeles, not only sponsored the great Jay Springsteen in Grand National Dirt Track, but also sponsored many top class riders in the Sportster-based Twins and Buell racing series – and in the Bartels’ workshop was a brand new, if slightly damaged, Buell racing engine. Apparently, the brand new H-D factory Buell racing engine had been damaged when it was dropped on the workshop floor as the Bartels’ mechanics were fitting it into a Buell race bike. Being a friend of Bill Bartels, persuading him to sell the engine wasn’t a problem - but as the motor was stamped ‘Race Only Use’ and had no identifying numbers, registering the bike with the Californian DMV could have been, if a receipt of sale from Bill Bartels had not proven the engine’s authenticity.
Bill Gately had the damaged engine mounting repaired and further tuned the Buell race motor by fitting a 1450cc, (88ci), big-bore kit using Axtell alloy cylinders and Wiseco 10.5:I high compression pistons. The Sportster-based crankcases had to be enlarged to accept the big-bore cylinders and the Buell crankshaft was rebalanced to suit. The engine also has a revised breathing system and features a Mikuni HRS 42mm carburettor and a Storz Supertrapp race exhaust system. The stock Buell race 5-speed gearbox drives through a Barnett clutch and Bill replaced the original Harley/Buell parts with a Dyna 2000 ignition, coil, 8mm silicon HT leads and a Carl’s Speed Shop billet aluminium ignition cover. The engine now produces 112bhp at the rear wheel with 110 lbs/ft torque at 3800rpm, and with fuel and oil the bike weighs 382 lbs, (173.6 kg).
The Champion chrome-moly tubular steel nickel-plated flat track racing frame with 21-degree rake was made by Bud Carroll of Champion Frames and modified for street application by Chris Talbott at Talin’s Machine, Torrance, California. Bill fitted the bike with full race Ceriani 42mm forks with adjustable rebound and dampening, Kosman billet aluminium fork yokes with 5-way adjustable offsets and a Storz 16-position adjustable hydraulic steering damper. The wheels are Chicane 6-spokes in polished spun aluminium with Continental 19-inch flat track racing tyres. Front brakes are Performance Machine 4-piston monobloc brake calipers with 11.5-inch floating brake discs and operated by a Performance Machine master cylinder with Russell stainless steel braided lines.
At the rear-end is a Champion chrome-moly steel box-section nickel-plated swinging-arm with Works Performance twin billet shock absorbers with 4-way adjustable ARS. Rear brake spec just as impressive as the front; Performance Machine 4-piston monobloc brake caliper with a custom 10-inch floating brake disc made by Precision Metal Fab Racing and a billet aluminium H-D type master cylinder with Russell stainless steel braded lines. Drive is by a Vortex billet aluminium 52-tooth final drive sprocket with Regina 520 O-ring chain.
The alloy fuel tank was hand made in California by Race Tech and is similar, if slightly larger, than an XR750 racing tank and the seat unit is also XR750, albeit made by Steve Storz. This where the special race-only parts end however, as Bill decided to use a stock Sportster oil tank and battery holder as he wanted the bike to have the initial appearance of a modified stock Harley Sportster and at first glance, ‘not too special’. Yep, in other words, a ‘sleeper’.
Bill Gately, Port Orange, USA.
Ex factory Harley-Davidson racing Buell air-cooled 4-stroke 45-degree V-twin with Axtell 1450cc, (88ci), big bore alloy cylinders & 10.5:1 comp Wiseco piston kit. Buell crankcases bored for big-bore cylinders. Buell crankshaft rebalanced.
Screw-on Scott’s billet oil filter assembly with washable stainless-steel element. Arlen Ness oil pressure gauge kit. Mikuni 42mm HSR flatslide carburettor with zero resistance Forcewinder air filter. Supertrapp polished stainless steel exhaust system. Buell OE 5-speed gearbox & Barnett clutch. Dyna ignition, coil & 8mm silicon HT leads. Carl’s Speed Shop billet aluminium ignition cover. Breather catch tank with filter. 32T gearbox sprocket. H-D Sportster oil tank. Bonneville Performance oil coolers. 112bhp @ 6800 rpm & 103 ft/lbs torque @ 3800rpm.
Champion chrome-moly tubular steel nickel-plated flat track racing frame with 21-degree rake made by Bud Carroll of Champion Frames, Redondo Beach, California. Modified for Street application by Chris Talbott @ Talin’s Machine, Torrance, California. Storz 16-position adjustable hydraulic steering damper. OTR weight 382 lbs, (173.6 kg).
Ceriani 42mm forks with adjustable rebound & dampening.
Kosman billet aluminium fork yokes with 5-way adjustable offsets. Chicane 6-spoke polished spun aluminium 2.75x19in wheel with Continental 130x19 flat track racing tyre. Performance Machine 4-piston monobloc brake calipers with 11.5in floating brake discs. Performance Machine master cylinder with Russell stainless steel braded lines. Performance Machine clutch lever assembly with Barnett braided stainless steel clutch cable. Flanders flat track ‘bars with Renthal grips. Aftermarket custom rear view mirrors.
Champion chrome-moly steel box-section nickel-plated swinging-arm with Works Performance twin billet shock absorbers with 4-way adjustable ARS. Chicane 6-spoke polished spun aluminium 3.00x19in wheel with Continental 140x19 flat track racing tyre. Performance Machine 4-piston monobloc brake caliper with custom 10in floating brake disc by Precision Metal Fab Racing, Shakopee, MN. Billet aluminium H-D type master cylinder with Russell stainless steel braded lines. Vortex billet aluminium 52T final drive sprocket with Regina 520 O-ring chain.
Hand formed 2.5 US-gal alloy tank & mudguards by Race-Tech, Oxnard, California. Storz flat track glass fibre racing seat with Saddleman pad.
Custom wiring harness by Owner. Bonneville Performance custom 7in Gunfighter headlight kit. LED tail lights. 12v sealed battery. Custom dash with ignition, high beam, neutral, oil, low fuel & turn signal indicator lamps by Bonneville Performance & Talins Machine. Electronic speedometer & tachometer from Bad Habit Motorcycles. Performance Machine switchgear.
H-D Racing Colours with Buell Pegasus logo by Jim’s Cycle Painting, Gardena, California.
Bike built by Owner. Custom fabrication by Chris Talbott, Talins Machine, Torrance, California.
Bill Bartels @ Bartels Performance, Marina del Rey, California; Chris Talbott @ Talins Machine; Jim's Cycle Painting; Race-Tech & Bonneville Performance, Port Orange, Florida. Web: www.bonnevilleperformance.com