Source: Bike Bound
[[{“value”:”A Spring-Frame, Square-Barrel TR5 Trophy from Ton Up Classics…
In the 1950s, Triumph dealer Bill Martin designed a spring frame for desert racing in Southern California. Production began in 1952, while Triumph wouldn’t offer a swingarm frame until 1954. It didn’t take long for Martin’s swingarm to display its potential in competition:
“Massive success came in 1953 at the Big Bear Enduro where Vern Robison came in first at the grueling desert race aboard a Triumph Thunderbird with the Martin conversion. It was due to that victory the frame was nicknamed the ‘Big Bear Spring Frame’. -Jonnie Green, Ton Up Classics
In fact, the ’53 Big Bear has been called the race that “started Triumph’s claim to fame in American racing,” with fewer than 1 in 5 riders even crossing the finish line.
“The 1953 Big Bear race had 448 entries, with only 83 finishing. Four newly made Martin Spring Framed Triumphs were in the mix and Vern Robison’s came in first after the leader Bud Ekins took out his Matchless in a slide.” –Show & Go Cycle Shop
As you can imagine, these small-production conversions are exceedingly rare today. This Big Bear special comes to us from Jonnie Green of Ton Up Classics, who was born and bred in Norwich, England, and set up shop in Los Angeles in 1988. Today, “Ton Up Jonnie” one of the top names in classic bike restoration, especially when it comes to post-war Triumph Twins and Pre Units. His restorations have taken home three prizes at the prestigious Quail Motorcycle Gathering — enough that he’s now an invited judge for the show.
Back in early 2022, Jonnie acquired a 1949 Triumph TR5 Trophy with a Big Bear Spring Frame conversion. Not only did the swingarm conversion make the bike unique, but the 1949 Triumph TR5 and 1950 models were fitted with the legendary Square Barrel top ends.
“Originally the cylinder and head were part of a generator set supplied by Triumph to the RAF for providing power to the Lancaster bombers during World War II. After the war the surplus of top end sets were then used on the Trophy TR5 and Grand Prix racers. The very first all alloy Triumph engine was born.”
However, the spring-frame, square-barrel donor Jonnie acquired was a far, far cry from the machine you see today.
“It was in a very sorry state, it had sat for the last 60 years outside.”
Jonnie had no real plan of action for the bike until the good folks from the Born Free Motorcycle Show asked him to be one of the 2023 invited builders. While Born Free was once focused more exclusively on choppers and bobbers, they’ve greatly expanded the range of customs on display, such as Todd Schuster’s “Tokyo Rose” CB750 drag bike we featured a couple of years ago.
“They now have sections for Desert Sleds and Pre Unit Triumphs so I thought this would be an ideal candidate for the show.” -Jonnie
Indeed! But Jonnie had only eight months to complete the build, and the work required was nothing short of monumental — a complete restoration.
“It was too far gone to even consider a preservation or patina build. No stone was left unturned.”
Jonnie was happily surprised to be able to salvage most of the original parts. The aluminum cleaned up nicely with vapor-blasting, and lot of repairs were made on various cycle parts. Everything was then sprayed black — there’s no powder on the bike.
What couldn’t be restored or acquired was custom-made:
“As you can see the exhaust ports are not splayed but come out straight, a pair of custom pipes were fabricated to suit.”
Interestingly enough, Bill Martin originally used front shocks from a Chrysler auto for his swingarms! Jonnie says it’s funny how similar the later Triumph units looked…perhaps the British engineers were keeping a keen eye on the work rolling out of Bill’s Burbank shop.
A vintage Bates solo seat and Wassell ribbed fender lend the bike those lovely sweeping lines, and Jonnie was able to get his hands on a pair of NOS Avon Trials and Sports tires to spoon onto the 19″ wheels.
Other parts were more challenging to track down:
“The TR5 used many unique parts not shared by the other twins.”
Fortunately, with well over 30 years in this business, Jonnie knows which trees to shake for old British parts. He overhauled the manual-advance BTH Magneto and fitted a new 276 Amal carb.
The Triumph logo on the fuel tank was hand-painted — no decals here — and one of Jonnie’s own bikes provided inspiration for the colorway.
“Black and Ivory in my opinion is a great color combination, I have a 1958 Tiger 110 in those colors that also remind me of the keys on a grand piano.”
In eight months, Jonnie managed to completely resurrect this piece of British-American motorcycling history, and the ’49 Triumph “Big Bear Scrambler” shone on the grass of the 2023 Born Free Show. In fact, it took home the award for Best Triumph Pre Unit — well earned! And the bike was recently featured in the 2024 Handbuilt Show LA.
Jonnie at HBS LA 2024
Incredible work, Jonnie — thank you for bringing this amazing bike back from the dead. We look forward to featuring more of your builds in the future!
Start-up Video
Full Gallery
All photos courtesy of Julie Green (@juliegreenfineart).
Follow the Builder
Web: tonupclassics.com
Instagram: @tonupjonnie
Youtube: Ton Up TV
Photos: juliegreen.net | @juliegreenfineart”}]]
