Tronsa Cafe Racer

Article By: Big Truth

Photos By: Joshua Elzey

Originally Published In The May 2013 Issue Of Cycle Source Magazine

May 2013 Feature 4aKerri Final

in the Course of human events, it becomes necessary for a shop known for its’ classic styled Triumph customs to dissolve the diplomatic bands that connected them with a customer base whom call for a similar styled bike again a n d again, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation… Ok, so we are somewhat a victim of our own success. If you know Choppahead, you know that we are largely responsible for revitalizing the custom Triumph movement for well over the last decade. We’re mostly known for building classic and timelessstyled Triumph customs. Not 100% chopper… and more than a traditional bob-job. A bike that retains its’ traditional Triumph styling elements and blends it in with a clean custom chassis. And if you didn’t know, now you do. Make no mistake, we love building our style bike. Apparently other shops do as well – as we’ve had a lot of kling-ons latching on and snugglin’ our nuts lately. But I guess imitation is the sincerest form of flattery. Anyhow, once in a while we get the urge to spread our wings, shake the metal dust off our sacks, and get into something different. Problem is, we are usually so inundated with bike orders from people asking for our traditional style bike that we don’t have time to pursue the other builds we’d like to do.

That changed a couple months back when a potential client e-mailed us a picture of a street-fightered out CB 750 and asked if we could build him something like it. This is what we had been waiting for. However, we don’t work on Jap engines, so we told him that we’d be happy to build him something – but with a Triumph powerplant. He bit and we got to work. So now we were on new grounds. Classic British Cafe meets Modern Japanese Street Fighter. Some say the two don’t go together – like high tea with crumpets and sushi. Well, we have weird appetites and can hold down anything we set our minds to! The term “Racer” is what bridges these two worlds, and that’s what we kept in our minds as we proceeded with this build. We started with the skeleton. While we love the tidiness and clean lines of a Triumph unit frame, we knew that it wouldn’t be the right frame for this build. Instead we chose a 1960’s BSA frame we had hanging around the shop. The engine cradle design suited what we were after more. We had to adapt the frame to accept the Triumph engine – more than just custom mounts was needed for this. We laid out a new path and bottom rail design to merge these two components together, and with some help from our friends at Acme (and their fancy Mandrel bender) it got done rather elegantly. In the end you’d think this Triumph engine was made for this BSA frame. At this point we still just had a classic British chassis. With some further modifications a Honda swing-arm (from a CB600) was installed. We wanted a more modern look, and modern handling – and a monoshock (tossing on some Hagons would be too easy). Remember we had our flying squirrel wings spread and flying freer than a bald eagle’s balls on this build…

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Prior to this build we had never touched a monoshock bike – so we had a little bit of a learning curve hurdle to jump with that. We knew what we were after, and we knew our geometry, but had to do some investigating on the right shock for this application. We made a couple costly mistakes before we realized that we were going to need something custom for this bike. So we called up our new friends at Works Performance in sunny California, gave them the low down, and they built us a custom shock that’s 100% badass in both function and form. Here’s a rundown on the rest of the bike… the rearset controls and rear brakes are modern Hinckley Triumph with some Choppahead re-engineering. The oil tank is a remote custom – Choppahead made – and hides under the aluminum rear seat cowl that our friend Pete at Cafe Cycles in RI crafted for us, the gas tank is a classic BSA, the front end is from a 2007 CBR600RR ( w e had to perform bearing conversion surgery to mate the front end to the frame), wheels are Warp 9 with custom Choppahead rotors to work with our Frankenstein’d wheels/ brakes/swing arm setup. All engine work was done inhouse at Choppahead – this 1976 Triumph motor was completely rebuilt from the ground-up. Paint was done-in house, as well. However, the pinstripes were hand laid by New England legend Charlie the One-Armed Bandit! All powdercoating (frame, engine, random bits – basically anything you see that is black) was done by our good friends at Goodhue’s in New Hampshire. The seat is a custom Choppahead seat pan, covered in leather by revered mountain-recluse Jay of Truckalope Leather.

In the end we feel this bike is a perfect blend of classic and modern styling, engineering, and function. And it’s fun and fast as fuck! We call it the Tronsa since it’s a well-balanced mix of TRiumph, HONda, and BSA… For more information on this bike and our shop visit: www.

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Choppahead’s Tronsa Tech Sheet

Owner: Matt

City: Boston, MA

Fabrication By: Choppahead Kustom Cycles

Year: 1975

Model: Triumph T140

Value: Alotta Quid

TIME: 6 Months


Year: 1975

Model: Bonneville T140

Builder: Choppahead Rebuild/OG Triumph

Ignition: Boyer Electronic

Displacement: 750cc

Pistons: .060

Heads: Bonneville

Cam(s): Stock

Carb: Amal 930s

Air Cleaner: Velocity Stacks

Exhaust: Choppahead Stainless

Primary: Stock


Year: 1975

Make: Triumph

Shifting: 5 Speed / Left Side


Year: 1968

Make: BSA

Rake: Stock

Stretch: None


Type: Honda


Extension: Stock

Triple Trees: Honda


Front Wheel: Warp 9

Size: 17”

Tire: Avon

Brakes: Choppahead Rotor/Honda Disc

Rear Wheel: Warp 9

Size: 17”

Tire: Avon

Brakes: Choppahead Rotor/Triumph Disc


Painter: Choppahead

Color: Satin Pearl White

Pinstriping: Charlie the One Armed Bandit


Bars: Honda Clip-Ons

Risers: None

Hand controls:

Gas Tank(s): BSA

Front Fender: None

Rear Fender: None-Seat Cowl by Pete Chase

Seat: Choppahead

Foot Controls: Triumph Himckley

Oil Tank: Choppahead

Headlight: Lucas

Taillight: Cat Eye

Photographer: Joshua Elzey

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