Jon Rosenstiel is an iconic Motocross Mechanic. He tuned for many of the Motocross and Road Racing Legends for nearly four decades. You know their names; they've won scores of races and dozens of championships with Jon R on the wrenches.
Riders such as Gary Jones, Marty Smith, Pierre Karsmakers, Tommy Croft, Warren Reid, Marty Tripes, Broc Glover, Donnie Cantaloupi, Mickey Diamond, Jeff Stanton, Damon Bradshaw, Doug Dubach, Jeff Emig, Doug Henry, John Dowd, Jeremy McGrath, and the list goes on.
Even the Corporate "Suits" recognized his expertise and value to their success and branding. The Japanese race and engineering staff admired Jon R for his technical abilities and work-to-win ethic.
Jon R grew up on a farm in northern Illinois during the 1940s and 1950s. By age six, he already had an intense interest (obsession) with electrical and mechanical things. Fortunately, his parents supported this obsession, resulting in a steady supply of mostly worn-out appliances, electric clocks, radios, TVs, antenna rotators, etc. And then there were the old and mostly worn-out automotive/truck/tractor goodies. He took apart everything he could get his hands on to see what made it tick. And if it didn't work, he tried to fix it.
Regarding reading materials, he had subscriptions to electronics magazines, and once his dad brought home a set of Audels electrical books from the 1920s. Jon R devoured them and tinkered constantly.
Consider this as a side note of how times have changed since the late 1950s. He once traded a pocket full of Cherry Bombs for a HeathKit VTVM (Vacuum Tube Voltmeter). He still has the HeathKit, but Cherry Bombs presumedly have long ago blown up a school toilet or a rural Illinois mailbox.
By the time he graduated high school, he was starting to figure out that "classroom learning" was not one of his strong points. He didn't want college, so he did a Navy deal that if he signed up before his 18th birthday, he'd be discharged the day before his 21st.
So, it was off to the US Navy. After radar school, he was assigned to a carrier-based attack/nuke bomber squadron, VAH-1. He did two 18-week Mediterranean cruises on board the USS Independence, CVA-62. He worked on the electronic equipment in the squadron's "close-to-retirement" aircraft, most still using vacuum tubes and dynamotors, repairing all the antiquated and heavy devices.
He spent quite a bit of time on the flight deck, working on aircraft, or watching flight operations. Night operations were very cool, and he particularly liked watching F4 Phantom Fighter/Bomber Jets take off at night under full throttle and after-burner. He admired one plane especially. The Douglas AD-6 Skyraider had an 18-cylinder, 2800 hp, Wright R-3350 radial air-cooled engine that made the sweetest sound ever," and when the pilot throttled back the engine, the stubby exhaust stacks emitted short blue flames. A gnarly sight to see on a dark night on a US Aircraft Carrier during the height of the Cold War in the Mediterranean Sea.
There weren't any active military conflicts going on while he served, though he was called back from leave because of the Cuban missile crisis. But the military lifestyle wasn't for him. When his time was up, he went to work for his dad (the owner of a farm tractor/implement and Honda motorcycle dealer) and started taking a few classes at the local community college.
Before long, he had another choice: a full-time job working on motorcycles or attending community college. He chose motorcycles. Learning by doing was his thing, and after a few years of repairing motorcycles, he applied to and was hired by American Honda Motor Co in California. He put a trailer hitch on his Camaro, packed up a U-Haul, and headed for California.
He was soon involved in the pre-production testing of Honda's latest creation, a 4-cylinder, 500 cc street bike. The testers' orders were to run the machines as hard as possible for as long as possible. They loaded up a truck with spare parts and equipment, jumped on their test bikes, headed for Nevada, and thoroughly abused them there and in the Death Valley heat. But the bikes were typical Honda; nothing fell off, and nothing broke.
His next stint was working on Honda's attempt at the World Land Speed Record at the Bonneville Salt Flats with the Honda Hawk. Then about a year later, Honda decided to enter the motocross market with a 250 cc two-stroke. As it turned out, he was the only test rider in the testing department who knew anything about motocross racing. Bingo a new career (obsession) as a mechanic in motocross and supercross racing that would last until he retired. (Eight years at Honda and 25 years at Yamaha) Note: he knows the word "technician" is preferred, but he likes "mechanic."
In mid-1972, Jon R also started play riding on his Ossa Pioneer up at Carol's (Warren and Wayne Reid's mother) Cabin up in the San Gabriel Mountains with many other American Honda and motorcycle employees who knew Carol and loved dirt bike riding on the weekend.
Those friendships flourished on dirt bikes, and at the end of 1972, Team Honda formed for the start of 1973 season, filled with Honda Employees that had been assembling at "Carol's Cabin;" Dennis Blanton (Marty Tripes' mechanic), Jon R (for Gary Jones), Roy Turner (for Rich Eierstadt), Ron Murakami and Dix Erickson (Special Projects and Fabrication) and the list goes on, including Dave Arnold, Rick Jones, and Merle Anderson who also joined the team in 1974.
Also growing in 1973 was the relationship between Jon R and Carol, who married before the year's end. Warren and Wayne became fixtures in the Team Honda pits and were general pain in the asses of Team Honda mechanics and riders trying to win races.
Jon R's career as a mechanic and suspension specialist is book worthy, and not a simple bio. But most noteworthy are his championships earned tuning for Gary Jones (Honda 1973), Marty Smith (Honda 1974 & 1975), Broc Glover (Yamaha 1981, 1983, 1985). In addition, he was quite successful as the full-time mechanic for Marty Smith in his 1976 125 World Championship Grand Prix attempt. Then with stepson Warren Reid (Honda 1977-1978), Marty Tripes (Honda 1978-1979 [together almost taking down the mighty Bob Hannah], Yamaha 1979-1980), and with Broc Glover (for his entire Yamaha career in the 1980s).
In 1974 and 1975, Jon R and Warren went to SoCal CMC races every "free" weekend and many weeknights. Warren progressed into a top SoCal 125 Pro and earned a top 10 in the 1975 125 Nationals (while hitching a ride in the Team Honda Truck while Jon R tuned Marty Smith to his 2nd consecutive 125 National Championship). Jon R had two riders in the top 10 that year. Jon R was often working closely with Don Emler and
FMF, in those years, developing go-fast engines and pipes for the CR125s and the legendary Honda RC125 Works Bikes.
The list of mechanics and team managers Jon R has worked alongside over the years is also legendary. Dennis Blanton, Roy Turner, Rick Jones, Dave Arnold, Merle Anderson, Steve Whitelock, Arnie Beamon, Bill Buchka, Brian Lunnis, Terry Mulligan, George Ellis, Cliff White, Gunnar Lindstrom, Kenny Clark, Larry Griffiss, Keith McCarty, Bob Oliver, Dave Osterman, Ron "Slicer" Heben, Bill West, Cliff Lett, Steve Butler, Steve
Mathes, Mike Guerra, and the list goes on and on, and hopefully, the mistakenly omitted folks will blame this author.
After Broc retired from his legendary Yamaha career, Jon R was made head suspension man for Team Yamaha. After that, virtually every Team Yamaha factory rider and many "support riders" tested with, and raced with, Jon R tuned suspension, winning many National and Supercross Championships and races. In the early 2000s, Jon R, was made head of Road Race Suspension and helped Yamaha Factory Road Racers win, including Anthony Gobert.
As retirement approached, he started surfing the internet for electrical projects to keep him busy. First, he made Tesla coils, including one so powerful that the arc (a giant spark) could jump a 5-foot air gap, much more than the 1/16” air gap of a spark plug.
Next came a diffusion-pumped vacuum system, a homemade x-ray machine, and other vacuum tube experiments. With the knowledge gained building and running a diffusion-pumped vacuum system, a Fusor project (low-level Nuclear Fusion) was completed…in his garage. Today, nearly twenty years since he produced his first fusion neutrons, his fusor still offers up interesting and often puzzling results, which means more tinkering to figure out “why?”
Of course, all of this “Nuclear” testing in one’s garage garners attention from important people who are supposed to notice this kind of stuff, even those at the amateur level. From that, Jon R eventually started running tests in his garage lab for various physicists from some of the US’s National Nuclear Laboratories.
The coolest machine he has is the Gamma Ray Spectrometer which detects sample elements down to the atomic level. He detected a very slight radioactive fallout from the Fukushima, Japan, nuclear power plant leak at his SoCal house soon after it occurred.
Eventually, the nuclear physicists invited him to White Sands Nuclear Test Site and gather test samples from “Trinity Site,” which was Ground Zero of the world’s first Nuclear Explosion. He used his home-built lab and compared the samples to similar test samples from the Soviets’ version of White Sands. Today, Jon Rs test results are featured at the Bradbury Science Museum, and those results confirmed old suspicions of the Soviet’s Fusion Nuclear Bomb aspirations.
Take a video tour of Jon R’s Garage. It’s amazing:
But even with all those highly technical and successful endeavors, his genuine and ultimate legacy is Jon Rs family life. He is the epitome of a loving husband and a caring and example-setting father, grandfather, and great-grandfather. His family has always been inspired by his inquisitiveness, patience (with us, but not himself), and attention to the smallest details. Plus, he knows how EVERYTHING works and helps us all understand it too.
Jon R spends his days continuing cool experiments in his garage laboratory. A number of his long list of racer and mechanic compatriots over the years have visited his laboratory, and they are as impressed with that as they were with his motorcycle tuning and mechanical/electrical aptitude. Dave Arnold has said that it makes him a hero to every other mechanic. So importantly, too, motorcycles were at the center of much of Jon R’s life, and his family and the motorcycle sport are so glad it did.