50 years ago Warner Riley began working toward having the World’s Fastest Conventional Motorcycle. With help from S&S Cycle in Wisconsin, topping 200 mph was the goal on a Sportster!
By August 1971, Warner Riley had already set two motorcycle land speed records each year since 1967. In 1971, he set the record in the MPS/AG class at 173.832 mph aboard a Sportster-based Harley-Davidson. That AMA record stands to this day.
But that year, he decided to kick it up a notch; he wanted to join the 200-mph club in 1972. To do that, a rider has to set a certified record with an average two-way speed of over 200 mph.
At the time, only 10 other motorcycle competitors had made it into the club—including Cal Rayborn who had set the absolute world motorcycle speed record with a fully streamlined Harley-Davidson in the S/AF class at 265.492 mph in 1971.
Riley told the story in detail in an article published in the March, 1973 issue of Harley-Davidson’s house magazine, The Enthusiast. That article, entitled “Assault with a Deadly Weapon” was reprinted from Big Bike magazine.
Warner Riley is one of the motorcycle land speed racing legends that inspired me first as a kid dreaming of someday getting to the Bonneville Salt Flats myself in hopes of setting a record and was still an inspiration when I actually got to Bonneville.
Indeed, Riley is noted among the land speed racing legends in the first chapter of my book, “The Unlikely 1” that inspired my Bonneville adventure 40 years later!
I found that issue of the Enthusiast at a junk shop so you can imagine my excitement at the chance to buy that little piece of history. I had also read about Riley, Denis Manning, George Smith, Leo Payne, George Campos, Dan Kinsey, Bud Schmitt, and other land speed racing icons in the book, “Heroes of Harley-Davidson.”
Riley’s article in the Enthusiast went into some interesting technical detail about how he and S&S Cycle co-founder George Smith went about preparing Riley’s record-holding Sportster to break the 200-mph barrier.
Smith would assist with, among other things, a special fuel valve to deliver the high-flow fuel volume that would connect the tank with the S&S Cycle carburetor via a ¾ in I.D. fuel line as well as the non-pump gas nitro fuel! Evidence you can’t feed an engine propelling its payload to over 200 mph with a sippy-cup.
Smith would also provide the hydrometer and thermometer necessary for temperature correction of the fuel mixture. The final drive ratio would be 1.96:1; necessary to reach 200+ mph. Riley tells the story of the 1971 effort this way:
“As it turned out, we did our homework very well, and after three gas runs to make sure everything was working right, and also to set a new gas record of 173.832 mph, we were ready. The 1.96 gearing was put on, 70 percent nitro was put in the tank, and the first run netted 192.71 mph, which qualified the bike.
“The next morning, with 86 percent nitro in the tank, I ran 198.237 mph going down, and 202.360 mph coming back, for a new record of 200.298 mph. Hurrah! We were in the club with only three runs! Mission accomplished! If I only realized what good luck we had in 1971, I might not have been as anxious to tackle 1972’s target. After accomplishing the 200 mph goal, my next objective was to have the world’s fastest conventional motorcycle.”
Riley’s work toward his 1972 goal began as soon as he got home from Bonneville in ’71. Complete disassembly of the entire bike down to the frame. Total engine rebuild, repainting, replating, the works.
Simply rebuilding his ’71 record-setting Sportster wasn’t going to get it done. Riley knew cheating the wind was key to his goal, so he consulted Dean Wixom of Wixom Brothers Fairings and Dick O’Brien, Harley-Davidson’s Racing Team Manager. With their input, the design for the fairing was developed.
The Sportster’s chassis and running gear got some attention, as well. The final drive was updated with the rear hub changed from a KR unit that could accommodate a 36 tooth sprocket to a Kosman hub that would allow fitting of a 28 tooth sprocket paired with a 25 tooth countershaft sprocket.
The steering head angle was raked to 34 degrees to provide 5 inches of trail for greater high-speed stability. A later model swingarm was fitted to add 2 inches to the wheelbase.
The nitro mix planned for the 1972 runs was to be bumped up from 86 to 92 percent and displacement was increased by one inch through a 0.020-inch cylinder overbore to the steel cylinders housing forged pistons, all from S&S Cycle.
In all, the new engine configuration provided 92 c.i. displacement, which Riley estimated at the time would produce from 165 to 175 hp, running a 92 percent nitro fuel mix. The XLR/XR heads were ported by Jerry Branch and the crankcase and oil pump were replaced with 1972 model units.
By the time he was done, Riley and friends, George Smith, Don Duncan and Don Baker had prepared three 92 cubic inch displacement engines—the upgraded 1971 engine, an all-new from-scratch unit, and a spare from George Smith’s own street Sportster. Riley told of how much preparation he went to besides the spare engines—evidence of his determination to reach his goal:
“I also prepared two close-ratio gearboxes and brought along extra clutch parts, chains, transmission shafts, magneto parts, tappets, pushrods, rocker arms, rings, gaskets, oil, spark plugs, clamps, wire, nuts, and bolts, and on and on. You pack everything you own and think you might need. As it turned out, we needed quite a lot of the extra items we brought.”
Incredibly, despite the enormous amount of forethought and preparation for the 1972 attempt, Riley revealed he never had started the main engine prior to loading the bike into the trailer and heading west to Bonneville.
He wrote, “The motor was built, bolted into the chassis, and away we went. In fact, one of the spares was finished the day we left.” The work went right up to the time of departure and there was no time left for engine testing.
Riley’s first runs were to be on pump gas instead of nitro. Despite the setup and weather conditions closely matching the previous year, the bike just didn’t have the speed. His first-down run was only 158.45 mph and after some final drive fettling his second run was only 139.10 mph. The spark plug condition seemed to indicate a problem with overheating.
Building a still air box around the carb’s intake helped, with the bike ranging up to 160.42 mph, but on the end of that run, the clutch release rods welded together, breaking the countershaft cover and release worm gear.
After spending the next day making repairs and changing to a 1 7/8 inch carburetor, the next run was no better, reaching 160.42 mph once again. Disassembling the engine revealed that the overheating had been caused by insufficient clearance and the top compression rings were broken.
The next day, the top of engine was rebuilt; and proving that haste makes waste, a red shop rag used to keep contamination out got left inside the engine, necessitating some disassembly to retrieve it. Turns out, they needn’t have hurried—the following day’s competition was scratched due to high winds.
The next day, Thursday, found the bike back on the salt with a best run on pump gas of 167.91 mph. Making the switch to 90 percent nitro, changing the gearing from 2.03 to 1.94, and changing the carb, the bike was ready for prime time—or so the team hoped. First run on nitro: 198.23 mph.
For the next run, the percentage of nitro was increased to 92 percent; jetting and plugs kept the same—result: disaster. The transmission access door fractured and took out half the gearbox and broke the crankcase. Repairs took steady work until 1:00 AM the following day, Friday, which was the final day of qualifying.
The work paid off—a qualifying run of 203.50 mph set the stage for a record attempt on Saturday. Despite the carnage of the past week, as Riley sat warming the bike up in preparation for the final record assault on Saturday morning, he felt confident.
As he rocketed through the timed mile, the tachometer read 5,400 RPM, Riley knew that with the gearing in the bike, that meant 200+ mph. He was right, his timing slip read 202.931 mph. His second run nearly ended before it got started, as he lost his grip on the car he was holding onto for his rolling start and nearly dropped the bike. Losing that time on the run-up to the timed mile, he realized he’d have to push the bike even harder. Which he did.
His speed for the measured mile 210.157 mph and the terminal speed for the last ¼ mile was 212.756 mph. His combined average was 206.544 mph—a record that stands to this day in the APS-AF class.
With having set such amazing records, you might think Warner Riley would have let the throttle wind down a little. And you’d be wrong. Riley was back at it and in 1974 set the AMA record in the M-AF class, which still stands at 199.5 mph!