Born Free: 1961 Triumph Pre-Unit Duplex Digger “Stretch”

Duplex Digger: Karl Ardo’s Pre-Unit Triumph Chopper…  

In 1960, the twin-carb Bonneville 650 received a new “Duplex” frame whose twin front downtubes corrected the “Whip Iron” wobble of the original bike. Today, the 1960-62 Triumph 650 twins remain popular for custom-builders, combining the Duplex frame with the iconic pre-unit engine.

Aptly nicknamed “Stretch,” this 8’10” 1961 Triumph pre-unit chopper comes from our old friend Karl Ardo (@zerobalancer), a multi-time invited builder to Born Free Show whose “Red Line” pre-unit bobber and restored Todd Schuster Honda drag bike have graced our pages in recent years. 

Tokyo Rose, Reborn: A Legend’s Honda CB750 Drag Bike

At 77 years old, Karl has been building hot rods and motorcycles for the better part of a century, starting with the ’32 Ford 5-window coupe he and his built when he was a teenager. 

“I was not on anyone’s radar screen in high school but when I showed up the first time in my yellow 1932 Ford with a full-house ’56 Olds engine I moved to the top of the Cool Guy list. Shortly after I had my first date.”

This chopper, built for Born Free 16, is what Karl calls a “digger”:

“Diggers are choppers that move towards drag bike, low and long. The challenge of building a British digger would be interesting. It needed to complement the soft lines of a classic Triumph, smooth flowing and sexy-looking; this was my objective.”

Karl has certainly achieved that vision with “Stretch” — viewed from nearly any angle, the bike flows with almost liquid grace, with a keen eye catching on one neat detail after another. The girder front end, corkscrew velocity stacks, finned exhaust clamps, built 650 engine, George Tantardini (@hoodoo_speedworks) paint — the list goes on and on.

Karl has written up a wonderful story of his lifelong passion for cars and bikes that culminated in this build, so we’re going to hand over the reins and let him tell you the tale in his own words. This may be his last project, as he’s “ready to come out of the garage and explore my surroundings” while expanding his Qigong practice. We encourage you to find him at his website: www.movinginstillness.com.

Karl, we’re not so sure this is the last project we’ll see roll out of your shop, but if it is, “Stretch” is one hell of a final build. Absolutely breathtaking, and with so much of your tight-knit community involved in various ways. Thank you so much for sharing your love, expertise, and rolling art with the rest of us. 

Pre-unit Triumph Digger: In the Builder’s Words…

I grew up in Connecticut, just your average small-town kid. Everything changed when I went to my first Firehouse Sock Hop in 1961. I was 13, much younger than most of the kids at the dance. Our firehouse in North Haven, CT was strategically located between New Haven, Hamden, Wallingford, and Harford. What showed up for me that first night in the parking lot were chopped Mercs, shoebox Fords, hot rods of all styles, and mostly Triumph motorcycles. I have not been the same ever since.

My first build was a 1932 Ford 5-window coupe. My father and I spent seven of the best months in the garage bonding; he learned as much as I did about more than just building a coupe. Once again everything changed in one day. I was not on anyone’s radar screen in high school but when I showed up the first time in my yellow 1932 Ford with a full-house ’56 Olds engine I moved to the top of the Cool Guy list. Shortly after I had my first date.

That was the beginning of me waking up from having no real direction, to a world of infinite possibilities. After graduating high school, I went to the Maryland Institute College of Art and from there the University of New Mexico in Albuquerque for my master’s degree. I was not building cars at that time but I always drove something cool.

After leaving college with my girlfriend (we’ve been married now for 51 years), we moved to San Francisco in the mid-70’s, perfect time to be there. Again, everything changed once we arrived: bought a house, got married, had our son. After a few years we decided to move back to Maryland to raise our son. The cool old Cape Cod house we bought had a detached two-car garage; back to building hot rods. Yippee!

We lived there for 25 years and six hot rods and three Triumph motorcycles later we moved to a magical house on a lake in Columbia, Maryland. The problem was it did not have a garage, but a good size furnace room; couldn’t build a car but perfect size to build motorcycles.

I thought this was going to be my happily-ever-after home until one day we got a call from our very smart son saying he just accepted a faculty position in the chemistry department at U.C. Irvine in Southern California, and his last statement was: “Oh by the way we’re pregnant.” Well, needless to say, we were moving to California.

We had two houses in California with garages that were already setup for me to build bikes and a few hot rods. We have been here now 12 years, we have two grandkids, and the move was so worth it. I have built 10 bikes and two hot rods since arriving.

My shop consists of an $80.00 Harbor Freight drill press, Dremel tool, cordless drill, 5.5” hand grinder and bench grinder, the usual assortment of files, screwdriver, wrenches, and a bench vice. I have the same set of Craftsman tools my dad bought me when we built the 1932 Ford back in 1961 that I still use today.

I was invited for a second time to build a bike for Born Free 16, this year. I had for a few years been thinking about creating a British-style Triumph Pre Unit Duplex Digger. I have a good friend, Scott, who is a collector and owns four of my bikes, and now the Digger makes five.

After the third bike he purchased, I was planning on starting the Digger that I’d been kicking around for a while and felt it was time to build it. Just when I was in the beginning planning stage, I got redirected when a pristine Triumph Pre Unit Duplex hardtail show bike frame came available — I couldn’t say no. Scott and I talked and instead of building the Digger, I decided to build a red bobber “Red Line.” Once that was finished, the Digger came back around, and at the same time I was invited to build a bike for Born Free 16. Timing is everything: Let’s Build The Digger “STRETCH”!

I’ve built a number of Triumph bikes in the bobber style, except one OIF Triumph drag bike and one restored Honda drag bike built by Todd Schuster. Bobbers are basically racing bikes that are street-legal, moving towards drag bike. Diggers are choppers that move towards drag bike, low and long. The challenge of building a British digger would be interesting. It needed to complement the soft lines of a classic Triumph, smooth flowing and sexy-looking; this was my objective. I wanted to use what I thought a Digger coming out of Europe would use: Wassell Banana Tank, Bultaco front hub, and Triumph hardtail, keeping all the modified parts looking soft and smooth. I wanted a very clean frame while retaining all the bungs and mountings on the frame and hardtail.

Josh Winderman, my creative friend, and I built the Triumph OIF (Oil in Frame) drag bike. We lowered the top section of the hardtail to get the seat lower and have it run parallel to the ground. What we didn’t expect is it took you from riding on the bike to feeling like you are part of the bike.

I wanted to replicate that style and feeling on the Digger. Kevin Corder, a fabricator from Detroit, extended the 1954 Triumph hardtail 8” to pull that off. The bike is 8’10” long, comfortable for a 6’2” person as well as a 5’8” person.

This was by far the most modifications on a bike build I have ever done. Fortunately I felt up to the challenge. I am so honored to be surrounded by so many talented people here and across the country that I can count on. I understand my limitations; for me to create these bikes I needed to rely on my circle of talented friends to move it to the level of my vision. If I did it on my own, it would have fallen very short of my expectations.

At its core it’s a modified Triumph 1961 Pre Unit Duplex frame with a modified 1954 Triumph hardtail done by Kevin. I’m using a vintage CCW girder front end with a Bultaco front hub and an all-aluminum rear hub. The engine is a 1961 well-built 650 Bonneville, with a lightened TT racing crank, 9.5 pistons, Q3134 cams, 9-bolt Bonneville head, Amal Monobloc left and right carbs, Joe Hunt Magneto, Slickshift transmission, Bob Newby lightened belt drive, Awardcycle one-off set corkscrew velocity stacks, and Burns Stainless custom exhaust.

To get the bike over the finish line it took a community of talented friends:

My wife Joyce is still with me after almost 51 years. Her support and understanding gives me the time and space to do what I do. THANK YOU!!!

Josh Winderman (@thedayolds): We have been involved with two hot rods and a number of bikes. His creative vision and fabricating abilities fall in the world of magic.

Kevin Corder (@kustomkevin): He exceeded my expectations taking a few drawings and creating the frame for the Digger, and besides that he made the seat for STRETCH also.

George Tantardini (@hoodoo_speedworks) has painted several of my projects. This one took me way outside my comfort zone. I gave George the feel I wanted and the color and left it up to him. He nailed it!!! He picked up on the movement flow of the bike and complemented the style and personality so the paint job did not compete with the bike. IT WAS MEANT TO BE!

Jeff Styles (@socalpinstriper) nailed the pinstriping PERFECTLY!

Burns Stainless gifted me SS mandrels to create the exhaust. This gift allowed me to explore possibilities that I would not have done and is such an important element to the look of STRETCH.

Lindsey Hover (@thebluecollarbarbie) works at @occarsinc. She is an amazing fabricator who welded my exhaust pipes, chain guard, brake lever arm.

Wheelworks (@wheelworksmc): Since coming to California they have done all my motorcycle wheels from building from scratch to just mounting tires.

Q&E Machine Shop has done all the machine work on all my engines.

Eli’s Polishing: I have never been disappointed in their polishing or chrome plating; short lead-times and extremely fair pricing.

Paul Hemshall (@awardcycle): I have used his cool parts on two of my bikes. I sent him a screenshot of a velocity stack that I used my finger to draw corkscrew lines on and asked if he could make these for me. Well check out my velocity stacks.

Ian Barry gifted me a set of beautiful petcocks and exhaust pipe clamps.

Scott Cline: My friend and supporter. Thank you!!

Mike Davis and Grant Peterson: These two guys and the hundreds of people behind the scenes that put on BORN FREE 16 are jaw dropping AMAZING!!!

I’m 77; this may be my last project; I’m ready to come out of the garage and explore my surroundings. Another side of what I do is I teach Qigong. I have a weekly zoom class and I’m looking to expand my classes. Check me out at my website: www.movinginstillness.com

Stay Groovy
Be Happy
Karl

More Build Photos

Follow the Builder

Karl Ardo: @zerobalancer
Web: www.movinginstillness.com

More from Karl Ardo

---