Donny's Unauthorized Technical Guide to Harley-Davidson, 1936 to Present: Volume I: The Twin Cam

Donny's Unauthorized Technical Guide to Harley-Davidson, 1936 to Present: Volume I: The Twin Cam

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by Donny Petersen

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Volume I: The Twin Cam is the updated first volume of Petersen's long-awaited Donny's Unauthorized Technical Guide to Harley-Davidson, 1936 to Present series. This twelve-volume series by the dean of motorcycle technology examines the theory, design, and practical aspects of all things Harley-Davidson.


Volume I: The Twin Cam is the updated first volume of Petersen's long-awaited Donny's Unauthorized Technical Guide to Harley-Davidson, 1936 to Present series. This twelve-volume series by the dean of motorcycle technology examines the theory, design, and practical aspects of all things Harley-Davidson.

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Donny's Unauthorized Technical Guide to Harley-Davidson, 1936 to Present

Volume I: The Twin Cam Donny Petersen
By Donny Petersen

iUniverse, Inc.

Copyright © 2011 Donny Petersen
All right reserved.

ISBN: 978-1-4502-6770-0

Chapter One

March 1998: Introduction of the Twin Cam

The Secrecy Agreement

In March 1998, Harley-Davidson invited me to Milwaukee along with Buzz Kanter and Chris Maida of American Iron Magazine. We some of the first outsiders were to join the select few who planned, designed, and implemented the Twin Cam 88. Our mission was to learn every facet possible about this new motorcycle and in turn teach the riding public through our writing. The following is written from a 1998 perspective.

Up to seven engineers taught us about the new motor for four days from 6:30 a.m. to 11 p.m.

Under secrecy agreements with Harley-Davidson, I was unable to talk about this honor until June 25, 1998. American Iron Magazine published my extensive articles on the Twin Cam 88 in its August 1998 issue thus introducing the world to the new engine.

Ya'll Ain't Gitten in der Boy! Dats were da secret stuff is.

The cabby asked. "Where ya'll going, boy."

"Juneau Ave, 3700 West Juneau Ave." I said.

"Wastin' yer time, boy." He admonished. "Ya'll ain't gitten in der. Dats were dey do dat secret stuff"

"You mean research and development?" I volunteered.

"Ain't dat what I said boy! I will wait here. Got me a two-way trip, cuz you ain't gitten in."

The old six-story building at 3700 West Juneau Ave. in Milwaukee looks exactly what it is, a pre World War II factory. It now houses H-D's corporate offices, normal and secret storage, and Harley-Davidson Archives.

The modern Milwaukee factories are located on Pilgrim Road, which normally does not offer tours and the Capitol Drive Plant that does have public tours. It has a little Harley store, which has exclusive souvenirs only available there.

Out front of the Juneau facility is a Harley's only parking lot with a "No Cages Allowed" sign. Surrounding this primo parking area are the less desirable parking areas for the cages (cars).

The security in the lobby inside was strict.

Enclosed in protective glass was a 1903 Harley-Davidson. It was gussied up to look better than it did back then. Its single-cylinder 3 HP belt-driven engine with no transmission contrasted greatly with the 95th anniversary Road King in the opposite corner.

After this article was published in American Iron Magazine, Dr. Martin Rosenblum, the official Harley-Davidson historian wrote a letter to AIM asserting that I was incorrect and that the 1903 Harley was indeed totally original and identical to when manufactured. The Letters column of AIM published his letter and my reply in the November 1998 issue on page fourteen. Dr. Rosemblum wrote, "Thank you for the wonderful piece you wrote entitled "Security at Juneau Ave." However, you made a serious error in referring to our 1903-04 Harley-Davidson as a "replica." It is not. It is the real thing. Please inform your readers that we have Serial Number One in our lobby for the world to see just as it rolled out of the original factory."

Dr. Martin Jack Rosenblum Harley-Davidson Archives Historian

Donny's reply:

I wrote "1903 Harley-Davidson that's been gussied up to look better than it did back then." I could tell the bike wasn't a replica but I commented to a factory worker who was conducting a tour that it sure was pretty. It was obviously nicer looking than it was in 1903. He laughed and said, "It sure is."

Donny Petersen.

We disagree but Dr. Rosenblum is an authority on Harley-Davidson and did a wonderful job historically documenting the history of this venerable company.

Harley-Davidson Secrecy and Security

Returning to the lobby, opposite the 1903 H.D., the Harley emblazoned black leather furniture sat in the third corner nearest the door outside. A security guard sat at the front door beside the enclosed black check-in counter. Above him in orange neon was the Bar and Shield, Harley's symbol.

After I identified myself, the secretary phoned the magic name I proffered and all of a sudden, I was okay. "Wait for security. Sign in this book, wear this security tag while in the building, and turn it in when leaving." Cameras were prohibited. "You must agree to random searches at any time. In addition, the legal department requires signing a confidentiality agreement. You are not allowed to discuss anything you see until June 25th." The date was March 18, 1998.

Do you have any idea how hard it was not to discuss the Twin Cam Fathead for three whole months while all the people supposedly in the know give opinions about what the Factory was doing?

H-D's top engineers taught us over the best part of a week. We have held each individual part in our hands, seen the completed engine and assembled Fathead bikes.

It was tough especially when the rumors for the most part were wrong. I bit my lip more than once. Having delicious secrets was no fun.

Why did they choose me? I never thought the Factory would approve me in the first place since I was not shy when it comes to being critical in my columns. However, the Factory said I was okay. I am aftermarket and definitely not a yes-man. However, I feel that I am diligent in attempting to be fair. The body language was already telling me the Factory people were confident that they had a winner.

I was not so sure. I had my list of structural complaints about the predecessor Evolution engine. Resolve the whole list with improvements in the new engine and you have a convert. The critic in me becomes loud and clear if this does not happen. The H-D fan in me laps on the praise when it does happen.

Boxes, purses, and bags are searched going in and out. As I wrote this, waiting for my escort to be like Velcro on my side, a security glared at me, officiously wondering what I was writing. Suddenly, I was off the hook as the guard was busy searching a briefcase of someone wanting to leave.

Weather had delayed my cohorts Chris Maida and Buzz Kanter in Chicago. Therefore, I found myself with a nervous Steve Peihl who was in charge of the press. He was great at keeping a secret and not so good at letting one out.

The elevators were the old style, pull-down-the-wooden-slat-door freight ones. We walked through a maze to get where we are going, which turned out to be the Harley-Davidson Archives. The door to the archives is always locked. It is necessary to bang on the door to get in and ask permission to get out.

The Archives

What a strange place to be viewing the future. "How come here?" I asked. "No one will suspect here," came the logical reply. Dr. Rosenblum, the fastidious H-D historian, didn't like this violation of his inner sanctum, but he consoled himself by watching history in the making. Once allowed inside, I immediately discerned the reasons for security and secrecy.

There it was ... a mechanic's dream. About 460 foreign-looking but somehow familiar parts lay in front of me, I easily identified maybe fifteen or twenty as being 1984-to-present Evolution motor parts. To the side was the complete Twin Cam Fathead engine while on the other was a 1999 Dyna Twin Cam motorcycle.

I was ecstatic as the group lead by "Skip" Metz began educating me. When realizing my teachers were the engineers in charge of design, testing, and production, I was in heaven. Leading the team was Bill Davidson himself who was extremely emotional about this new milestone for Harley-Davidson. His grandfather must have felt the same way in 1936 when he introduced the new overhead valve Knucklehead that replaced the old Flathead side valve technology.

The Washroom

By now, Buzz and Chris's plane had come in from Chicago. The engineers had to teach all over again. This was great. I sat back and listened. I was now concentrating on the mechanical theory relating to the newer technology. I began conceptualizing how everything interacted.

We needed pictures, many pictures. We gained security clearance from Steve. However, the archives were too dark for crisp, informative photos. We had to improvise somehow. Chris returned from the locked washroom across the hall. He said the light was great in there. Over we went carrying all the parts. The old-style washroom had lots of white marble, space, and big factory-style windows. We all reconvened in the washroom the next day, taking numerous pictures of each part and the subassembly it fit in.

After we relocated, poor Skip explained in detail, once again, everything about each part for the third time. I then understood every component, conceptualized how the different systems like oiling, breathing, and the spark map matrix worked. I also appreciated the noise and emissions aspects imposed by government regulations. More importantly, I grasped how they would influence the Fathead and the future.

My immediate impressions were all very favorable. This was some engine. This was a wave of the future for Harley-Davidson and it was a bright future indeed.

I'm posing with a prototype Dyna Twin Cam in March 1998. The location is in the hallway in front of the Harley-Davidson Archives on an upper floor of 3700 West Juneau Avenue in Milwaukee, Wisconsin. Surrounded in secrecy, we could not release information until June 25, over three months later. Inside the Archives, a disassembled Twin Cam engine was spread out before us. The designing engineers intensively taught us for three full days from early morning until late at night. Harley personnel are passionate, very committed, and work long hours.

The Fathead Name

During lunch one day in Milwaukee before the introduction of the Twin Cam, I was able to help nickname the new engine as the Fathead. Harley-Davidson never promoted this descriptive moniker. American Iron Magazine referred to the Twin Cam as the Fathead for many issues, using it everywhere.

I believe the reason was that we at AIM coincidentally came up with the H-D secret Fathead nickname. We started to use it in print before they were promotionally ready. Harley lore and tradition dictates that every engine has a nickname like the F-head, the Flathead, the Knucklehead, the Panhead, the Shovelhead, the Blockhead (Evo), and now the Fathead.

AIM editor Chris Maida, publisher Buzz Kanter, and myself, the Techline columnist since 1992, were sitting around during a break from our education on the Twin Cam 88. We were tired but constantly stimulated by the onslaught of new information swirling around us. We tossed around possible names like the Splithead because the rocker boxes split into two pieces but always came back to the Fathead. Really, what else could we call this oversized squat engine? The Fathead nomenclature based on the fatter top end on the Twin Cam 88 due to 60 percent more finning on the .250"-bigger diameter cylinders and heads. The combination of the bigger piston bore and the most massive cooling fins ever used on a Harley made this name a natural. Yeah, we could have called it something like the Bighead but the word fat has a special place in Harley lore because of the astronomical success of the Softail Fatboy. Arnold Swarzenegger riding a Fatboy in the movie, the Terminator, branded the name in the public's mind. In the wacky world of Harley-Davidson the ultimate, rebellious cool was fat, the antithesis of society's obsession with thin.

Now I was in trouble. Trev Deeley was the very influential Canadian on Harley-Davidson's board of directors. The rumor that he was a financier and a savior of Harley-Davidson during the buyout from American Machine and Foundry, renamed the AMF Company in 1971 was part of the lore surrounding the man. Deeley set me straight on my audacity in nicknaming the new engine. "You fucked everything up, Don! You and those magazine people have no right to do this!"

He was an irascible, good guy, if he liked you. His mercurial temper did not suffer fools gladly. Trevor was not crude, but he spoke plainly and was not above scowling, swearing, and raising his voice to make his point. He was a sharp pencil and Canada's most successful motorcycle importer, introducing many bikes, including Honda, to our shores.

This avid, lifelong motorcyclist would piss off his business-oriented motorcycle dealers. Before he saw these dealers, Trevor usually visited me first at Heavy Duty Cycles when he flew into Toronto from Vancouver. After all, I was the symbolic aftermarket enemy. He did not like a lot of them. He viewed many dealers as lazy, complaining, spoiled brats. It would drive him crazy that some of his people would play golf in the afternoon instead of working. Trevor used his dealer network to make money, lots of it, but the dealers were not his kind of people.

He would shoo my friendly but formidable dogs Huey, a 165-pound Great Dane, and Beau, a 115-pound Shepherd-Bouvier, out of the way, sitting down uninvited on a greasy, stained chair, and go into one of his wonderful rants. My dogs would eyeball me, then him, warily back and forth to see if I felt threatened. If so, they would take care of this blustery intruder. After awhile, they ignored Trev, because they could see how much I enjoyed his company. I will tell you one thing: His dealers never ignored him. He was on them even if they were doing everything right, which, of course, was impossible.

He would tell me that if I would quit my motorcycle club, the Para-Dice Riders ... it was bad for the new H-D corporate image ... he would make me a rich man. He knew I would not quit for money and he liked that.

One time he said, "How come you didn't attend my dinner roast?" It was a big ta-doo honoring him. I had heard about it but did not think I was that welcome or that he even wanted me there, not to mention it was 3,000 miles away. "Why didn't you invite me," I asked. "You need a godamn invitation?" he bellowed. He then said, "The Hells Angels came. I got restless at the head table listening to the bullshit about how great I was. They went outside so I grabbed a couple of beers and went out and hung out with them around their choppers. Told them they should not cut up a Harley that way, but you could tell they knew their way around their bikes and a wrench. Nice fellows, 'course I understand they're not always that way," he said with a mischievous wink. Trev liked them on an individual basis because they were bikers. They just were not his kind of motorcyclist.

Another time he was frustrated because he did not know how to quell dealer whining at a dealers' meeting. "What am I going to say to these complainers?" I suggested, "Where else in the world in any franchise can you become a millionaire in three years not knowing what you were doing!" He looked at me stunned. He did not say anything and the conversation drifted elsewhere. Did he ever say that? I do not know, but he was sure capable of it.

One time he said, "Do you want to be a dealer?" "Not me, man, besides I'm in a bike club and you guys won't tolerate that." "Aw, screw that, Don. Just don't sell aftermarket parts and you can have what you want." Of course, it did not matter that Trev's personal dealership sold many aftermarket parts. "I wouldn't have to Trev. H-D has many good parts coming down the line. Many of your dealers are not bikers so they don't know what the riding public wants. They don't know what to stock and what sells."

"Where would you like one?" he repeated.

"Well Trev, there's a nice spot up north in the country, but the dealer there is too greedy. He would want too much money." Trev surprised me with his answer, "That pompous pain in the ass, I've been looking to get rid of him. It's yours. No money, just show you are financially capable. There are the setup building costs and, of course, inventory. Find a good location in the area. What does he own after he loses the H-D dealer license?"

Trev was right in his assessment of that dealer, but then I a changed gears to lead into my next thought about a location. I said that I had been down to Milwaukee to view the.... "Don't say it!" Trev growled. "You signed a secrecy agreement" "Fuck, Trev, if I can't talk about it with you, then who?" "No one! It's a nice engine though, eh, Don? We are moving along good." Maybe Trev greased the way for my invitation to be one of the first to see the new engine.


Excerpted from Donny's Unauthorized Technical Guide to Harley-Davidson, 1936 to Present by Donny Petersen Copyright © 2011 by Donny Petersen. Excerpted by permission of iUniverse, Inc.. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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Donny's Unauthorized Technical Guide To Harley-Davidson, 1936 To Present 2.5 out of 5 based on 0 ratings. 2 reviews.
Anonymous More than 1 year ago
The print version of this book is one of the best on the subject, but the Nook version is unreadable. Being a technical book it has a lot of numerical content that does not display properly in the Nook version. Most of the fractions are displayed as a "?" (question mark) and other technical symbols are not rendered at all.
Anonymous More than 1 year ago