First, some kind words from Chris Maida, editor, American Iron Magazine.
“As the editor of American Iron Magazine, I have known and worked with Donny Petersen for over 11 years. To this day, the depth of his knowledge of Harley-Davidsons, both old and new, is still astounding to me. I have been riding and wrenching for almost 40 years. During that time, I have met lots of knowledgeable mechanics, designers, builders, and engineers. Moreover, in my opinion, Donny ranks up there with the best of them in knowledge and experience. –,”

Donny’s Books
Donny has finished Volume I: “The Twin Cam” the first edition of a 12 volume Harley Davidson technical encyclopedia.
The series of books called “Donny’s Unauthorized Technical Guide of Harley Davidson 1936-2008” are titled
The Twin Cam
Performancing the Twin Cam
How It All Works
The Sportster 1952-2009
The Evo 1984-99
VI. Performancing the Evo
VII. Shovelheads 1966-84
VIII. Lubrication
IX. General Harley Tech
Panheads, Knucks, and Flatheads 1936-65
XI. Tech Tips
Living the Dream

Donny has been working on Harleys since 1969.
He originally pursued a career in academics studying first to be a town planner but settled in as a social worker hanging out with the street gangs in Toronto’s toughest housing projects on the streets, at night.
With the early Seventies advent of psychedelic drugs, Donny was thrust into crisis intervention on the streets having to deal with bad trips, freak-outs and overdoses and all that went with them.
During this time, he purchased his second Harley, a 1966 Shovelhead. Harley Davidson became his sanity as Donny began learning how to fix his new passion.
He found mechanics very satisfying as there is a cause for every effect and vice versa. The answer is always there for the analytical mind.
Donny left mind-bending social work for the relaxation of an answer for every problem in fixing Harley Davidson’s.
Soon after, he proudly finished his first chopper, a day-glow painted, radically raked, twelve inch extended wide glide with no front fender and ape hanger handlebars.
The same summer while riding, he was center punched by a car in an intersection, breaking his back and leg in over a hundred places.
He refused to have his leg amputated at the hip.
On crutches, with a 1959 Panhead, replete with suicide clutch and hand shift, he began his 36-year membership sequentially in two prominent motorcycle clubs.
Sometimes it is not easy being a little different in a homogenous world.
Heavy Duty Cycles
A few years later circa 1972, the urge to become entrepreneurial overcame him. Donny worked out of back alley garages in Toronto’s tenderloin before formally starting Heavy Duty Cycles in 1974.
In 1977, he became a licensed mechanic.
Living on the streets as well as in academia, riding in the hardcore lifestyle of the day in addition to a blue-collar trade gave Donny interesting perspectives on life.
His schooling didn’t go to waste as his studies in advanced physics allow him to apply these principles to hi-performance mechanics such as porting and polishing and cam design. High-speed handling and braking packages are also an advantage derived from Donny’s education integrated with his mechanical skills.
Tech Writing
Donny became a tech writer in 1989 and his articles are read worldwide. For a number of years now he has been the most read Harley technical journalist in the world.
Master Bike Builder
His hand fabricated motorcycles have been featured in publications in Great Britain, Russia, France and Japan as well as closer to home in magazines such as Easyriders, VQ, American Iron, Hot Bike and, of course, Canadian Biker.
Donny was first described as a "Master Builder" by Supercycle Magazine in the 1980’s and was subsequently awarded this status by VQ and Easyriders Magazines.
But, Donny is the first to acknowledge that no one person can fabricate the bikes that the Heavy Duty Team always aspires to. It requires a team effort by the industry’s best and Donny confers this honor on the Team of which he is only a part.

Teaching
Donny began to put back into the industry that has become his life and began to teach aspiring mechanics.
For three years he taught every apprentice motorcycle mechanic in Central Canada, (involving travel of up to 1300 miles for the apprentices) for 16 weeks before they could write for their mechanics license.
He then collaborated with the Canadian Provincial and Federal Governments in updating and standardizing these courses for the whole country.
Donny then became the primary writer of the final computer generated Mechanics Examination utilized across Canada in order to produce standards respected world wide.
The Federal Government invited Donny to teach the Havana Harley Riders Club at the Canadian Embassy in Cuba as a goodwill gesture to the Cuban people in 1997 looking forward to a post-Castro democracy.
Finally the Minister of Education appointed Donny to the committee for implementing a new Education Act.
Donny soon became the chairperson of this committee.
However Donny became a political liability to the government and was fired, they called it un-appointing, for his membership in his bike club.
Biker Civil Rights
Along the way, Donny, with committed friends spearheaded many bikers’ rights initiatives to fight discriminatory policies directed against bikers and motorcycle clubs for the last two decades mostly to no avail. Donny refers to this as “pissing into the wind”.
One constitutional challenge to Canada’s Supreme Court led to another honor that of being invited to speak to the prestigious Empire Club in Toronto's Royal York Hotel. Fellow speakers over the years included George Bush Sr., Ronald Reagan and Billy Graham.
Donny proudly relates that his invitation distinguished him as one of the few no-name speakers.
Hobbies
An avid scuba diver, Donny’s first open water dive was in the South China Sea off the coast of Borneo looking for whale sharks.
Other hobbies include mountain trekking.
He has trekked the Inca trail from the center of the Incan empire in Cuzco in the Andes to Machu Pichu in Peru.
Donny then climbed Africa’s highest mountain, Kilimanjaro in Tanzania.
His next venture was Mount Everest in Nepal where he contracted both forms of the deadly and fatal acute mountain sickness as well as curable but still deadly Dysentery.
Donny had to make his way down the mountain for two days to get to a lower altitude for a possible rescue attempt as helicopters and small planes can only fly so high.
The three-day rescue off Mt. Everest by Sir Edmund Hillary’s personal pilot is a high point in Donny’s life.
The helicopter almost crashed because of big rocks inside the clouds during the flight back to Katmandu.
Then weather forced the helicopter down into a gorge for a night interrupting the very dangerous flight.
Travel Writing
Donny’s bike trips across North and South America, Europe and most recently South Africa have led to many motorcycle travel articles that are enjoying some success.
He describes his bike trips in fascinating detail as he winds up in many precarious situations…like running out of gas in the middle of nowhere in Africa with night rapidly closing in.
Many of these articles can be found on the website.
Biker T.V.
Millions of viewers have enjoyed his and Tattoo Tony’s technical segments on Canada’s weekly motorcycle show Biker TV as well as their appearances on The History of the Chopper.
The Honor
In March 1998, Donny was invited to Harley Davidson in Milwaukee as the first journalist to see the Twin Cam 88 "Fathead." Up to 7 engineers taught Donny for 4 days from 6:30 am to 11pm on the new motor. During lunch one day, Donny was able to help name the new engine the "Fathead". Under secrecy agreements with Harley Davidson, Donny was unable to talk about this honor until June 25, 1998. Donny's extensive articles on the Twin Cam 88 are published in the August 98 issue of American Iron Magazine introducing the world to the new engine. Extensive tech literature also appears on this website.
Donny’s Unauthorized Technical Guide to Harley Davidson: 1936-2008
Donny has finally decided to take pen, (actually a computer) and to lay down on paper his accumulation of H-D knowledge learned over a career spanning 40 years.
The twelve volumes will be finished over the next few years and may include further volumes as Harley Davidson introduces new models and engines.
“Volume I: The Twin Cam” has now been published as of November 2007. The 430 pages both in soft cover and hard cover will be updated yearly to keep it current.
What is the future?
Donny will finish his twelve volumes of his Unauthorized Technical Guide to Harley-Davidson 1936-2008.
He has a passion for revisiting Everest.
He will ride his Harleys.
He will remarry in a few years or he might not.
Moreover, he is currently planning to take the time to trek the
Medieval pilgrim’s walk from France through northern Spain; ride the entire coast of Italy; party in Dubai; take the world’s highest train from Shanghai on the coast of China all the way to Lhasa in Tibet; ride the Garden Route and the Wild Coast in South Africa and then ride up into Zambia looking for adventure and whatever else comes his way.
However, Donny’s first love is working with his customers at Heavy Duty Cycles where he looks forward to every day.
Donny the workaholic will be at Heavy Duty Cycles in Toronto right up until they carry him out in a casket.