50 Years at Bonneville
Scott Guthrie Remembers
Chapter #32
Time to retire.Warner Riley, 212 mph (In 1970!) Harley rider from the Chicago area, was advertising in the SCTA bulletin to SELL a pair of NEW Goodyear LSR Motorcycle tires.
Always short of cash, I felt I had to sell my pair of Firestone car LSR tires in order to buy the Goodyear LSR tires. I worried about that.
Riley, a long time Bonneville 200mph Club member, sent me his only remaining set of the elusive LSR motorcycle tires; one front, one rear. NEW ! Possibly among the last LSR motorcycle tires to leave Akron ! These tires were manufactured in 1974, so for the summer of 1978, they would be officially 4 years old???..
I immediately invested in special custom-cast aluminum wheels ? at great cost ? to fit the Goodyears.
Photo - Scott Guthrie 1978 Drawing. New fairing for single engine turbo Harley. Centers of gravity were estimated. Lower profile, with tank in the seat, better aero behind the rider, more teardrop shape. Seat design much like what Eric Buell and I would use in the 1980?s, and would be adapted by Charlie Toy in the 1980?s and 1990?s. Ellen Guthrie used entry number 5 in 1976, and I wanted to keep that number. Harley national champion and factory racer ROGER REIMAN claimed AMA #5 for his post-championship ?permanent? number (Only former champions of the AMA could choose a single-digit number other than #1). Roger had helped me a LOT in the early 1970?s and I wanted to honor his help with #5 at Bonneville. Roger designed his own ?typeface? for his #5, so I did the same. Repeats of #5 (top left) allowed several class changes, so I was prepared to have the ?double nickel,? the ?triple nickel? and the ?Quadruple Nickle? racing number. Notice how much this 1978 design looks like Hiro Kioso?s 2018 bike. The AIR hasn?t changed.
Tires ! It?s always the damm tires !
Although Goodyear had no such policy, the AMA demanded that tires ?declined? in safe speed capability by 25 mph per year after manufacture. Storage, use and visual condition was not a factor, so I would not be able to use that rumored Burt Munro trick of hiding the sidewall cracks with black shoe polish.
Originally, these skinny new Goodyear LSR tires were rated for 300 mph. FAR in excess of my needs. The SCTA ? bowing to the AMA (American Motorcycle Association) - who administered the SCTA?s motorcycle program - quickly informed me these BRAND NEW tires were unacceptable.
The 25 mph annual ?depreciation? made things difficult for every fast motorcycle racer. The Rule Book wording said that ONLY LSR tires could be used in excess of 200mph. Since there were exactly ZERO other motorcycle tires fitting this description, that meant that NOBODY would be allowed to exceed 200 mph on bike tires ? streamliners included ! That is an odd sort of ?bracket racing? situation for a contest that is supposed to reward ultimate high speed.
This lead to an interesting telephone conversation.
Regardless of my future speeds, my consuming goal was to join the Bonneville 200 Miles Per Hour Club, specifically on gas. In the 1970?s on a single-engine gas normally-aspired motorcycle, this was quite hard to do. I appealed the tire rule to the top of the AMA, and the conversation went something like this:
Scott Guthrie: ?I want to run 200 mph and join the Bonneville 200mph Club. I?m using a NEW Goodyear LSR tires.?
AMA: ?Sorry, that tire was made in 1974, in 1978, we only can rate that tire to 199mph, and then 175mph in 1979.?
SG: ?So, if I qualify at 202mph, what happens ??
AMA: ?Then we do not allow you to run for record the next morning. Further, your week is over until you change tires.?
SG: ? Well, If I can hold my qualification run to 198 mph, and then I go down the track at 202, and return at 205, what happens ??
AMA: ? If you go down at 202, you are done, and you don?t return.?
SG: ?What am I supposed to do ??
AMA: ?The only way this can work for you is to qualify under 200, make your down run under 200, and go for it on your return run. Then your week is over.?
Like so many others of us, I had been brought to my knees by the tires?
.and the rules.
So, I quit digging !
Don Vesco somehow heard about my situation, and called to buy my ?useless? tires. I sold him the beautiful unused tires; no further good to me. Thankfully, Don was willing to also buy my expensive but now-useless wheels in the bargain.
Don immediately fit these very same tires to his 300mph motorcycle streamliner, and ran on ?private time? with the FIM, which was NOT subject to AMA safety rules. Vesco, with a vehicle weighing TWICE as much as my ?lightweight? Harley, set a new world record at 303 mph
?..On tires that the AMA would only allow me to run 199 mph.
It seemed, after Selling my Firestone tires to Gordon Hoyt and the Goodyears to Don Vesco, that I had turned from being a racer to being a tire dealer?..I also had the sneaking suspicion that I should NOT have sold the LSR tires-which were impossible to replace?..
I felt like a character in a Shakespeare play: Selling one set of tires to buy another pair, and then maybe having to sell the second pair to buy back the 1st pair for the NEXT bike?..
Trying for the Bonneville 200 mph Club would have to wait !
I just didn?t think it would be 10-15 years !
I can go faster than the Factory can???..Right ?There was NO WAY beat the factory guys on talent or money.
I was pretty short of brains too, so this would be a tough fight.
I campaigned my 1972 XRTT ( with #41A) - with a 1957 sportster motor successfully (That was all I had at the time) well enough that I was eventually ranked 3rd nationally in the AMA in some obscure amateur class.
But I showed at least that I could do something.
Photo ? My old #41 in current form as it looks today. I believe this is the ONLY (one of 2) 1972 Factory racer Harley XRTT?s that has been owned and raced by only one person in the last almost-50 years........ I bought the chassis NEW through a Harley dealer in 1972, and kept the original receipt............ ( So rare that less than 30 complete bikes were built) Recently, I shipped the bike to John Steel in Ohio. John restored the chassis correctly, and installed an old engine I owned, that had been raced by AMA #1 MARK BRELSFORD back in the day - with the factory paperwork to prove it !.....CORRECT 1972 engine and correct 250mm Fontana 4LS front brake.
One way to get the attention of the Factory ? and perhaps convince them you are worth supporting ? is to do something technologically AHEAD of them. For me, that was to have BETTER BRAKES??
Part of the hope was to gain some ?creditability? with Milwaukee, and maybe get secret information, and maybe ?unobtanium? racing parts.
Photo - When Harley designed and sold these rare XRTT bikes, (only about 30 complete bikes were built) they came equipped with the icon of all front wheel drum brakes, the 250mm Fontana four-leading-shoe. These were usually laced with wire spokes to an 18 inch narrow rim, and supplied good stopping power. They were troubling to maintain ? with warping from excess heat of high-speed stopping ? and they were VERY expensive. Today, a replica wheel might be $3,500, and would be VERY heavy. Notice the size of the brake compared to the rim. Huge rotating mass made the bike hard to turn. As my friend Kevin Cameron put it: ?You need that big a brake to stop a brake that big!?
Photo - I NEVER raced my 1972 XRTT with the huge drum, having beaten the factory to the use of easily-available and inexpensive HONDA CB750 disc brakes. Cheap, little maintenance, and much more effective. 1973 Photo by Virginia Miller.
Instead ? YEARS ahead of the factory, in 1970, I was using DUAL Honda CB750 front brake discs. The Honda disc brakes were the first production disk brakes on motorcycles, and the design was quite conservative ! The individual disc weighed in at a WHOPPING 6.5 pounds. Hardly racy, but good for long life without warping with thick metal.
I tried the stock dual discs in racing, and the steering effort was way too high. My initial answer was to machine the discs down to about ? original thickness ? about the same as today?s units.
Photo ? Two stock discs on left, three ?skinny ? discs on right.
Original disc weighs in at a stunning 6.5 pounds !
Photo - ?Shaved? disc is svelte at less that five(5) pounds ? more than 1.5 pounds of heavy stainless steel removed ! Times two for two discs, that?s THREE pounds us useless metal and unsprung weight GONE !
Photo - Well, I wasn?t done !.....STILL too heavy for short tracks where heavy braking was not often needed, and lighter weight was better that ?thermal reservoir.?
Photo - I drilled six rounds of 36 holes ? which is 216 holes PER DISC ? more than 400 holes total. However, the disc lost ANOTHER 18 ounces ! ? that?s a total loss for both discs of almost six(6) pounds ? almost the weight of a single original disc. AND with WAY more braking force.
SOMETIMES, a privateer can get ahead of the factory?.