Triumph Bonneville Bobber Build, Part 1

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Here’s what our brand new Bonneville looked like when it arrived at the MC offices.
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Here’s our brand new Bonneville after an afternoon spent pulling it apart. Now the real work begins - putting it together the way we want it!
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We're going to drop our Triumph down a little closer to the ground, and to do that we'll install a set of shorter aftermarket performance shocks and also push the front forks a little farther up into the steering yokes.
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Proably the hardest part of our afternoon's work was removing the stock exhaust system, which we'll be replacing with an aftermarket unit. The first step in removing the exhaust is loosening the crossover pipe connecting the left and right sides.
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Next up is removing the nuts holding the header pipes to the cylinder head. Best practice is to just crack the nuts loose, one after the other, before loosening them completely.
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To get to the bolt that holds the rear of the header pipe you have to remove the right side cover, shown removed here, followed by the right side foot peg/brake pedal assemly, which you'll see in the next photo.
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After removing the side cover we also removed the right side foot peg/brake lever assembly. That's necessary to access the bolt that holds up the rear of the header pipe, which you'll see in the next photo. This photo shows the exhaust system already removed.
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Here you can see the rear header pipe mount. There's no good way to remove this bolt without first removing the side cover and the foot peg/brake pedal assembly.
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The muffler is held on at the rear by the rear footpegs. We're going to install a solo saddle which means we won't need rear footpegs, so these aren't going back on.
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Removing the headlamp shell is easy because the wiring is mostly fool proof thanks to unique terminal ends for each cluster of wires - with the exception of the turn signals, which use the same black/white wiring left and right but plug into different colored receptacles. We made sure to tag the wires in the loom for left and right signals.
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Here's a closer view of the rear of the frame with the fender removed. We're going to cut or "bob" the upper frame rails where they kink inwards before reaching back to the rear of the bike. The wiring will all nest nicely under the solo saddle we're going to install.

We’re building it, but you could own it. When we’re done, the Motorcycle Classics/Dairyland Cycle Insurance Bonneville Build could be yours. Just sign up to win . We’ll be giving the bike away at the 6th Annual Barber Vintage Festival Oct. 9, 2010, and we’ll be showing it off at shows across the country this summer. Look for more info online and elsewhere in this issue! 

Coming off our last project, the 1973 Honda CB500 Four we transformed from a junkyard reject to a smooth looking and smooth running café for the street, working on this new Triumph Bonneville is almost like taking a vacation.

Where every nut and bolt on the Honda was stuck in place from 35-odd years of accumulated rust and grime, the Triumph’s are held only by thread locking paste and torque. It’s a bit of a surprise to put a wrench on a bolt and have it actually turn with applied force instead of sticking solid while the wrench tries to spin on the head.

A bobber?

Yeah, a bobber. We know there might be a doubting Thomas or two out there, but the fact is the bobber theme has been around long enough to make it a classic in its own right.

Although a lot of folks will tell you the bobber style — bobbed fenders, minimalist decoration and lots of self-made parts — originated with returning servicemen in the post-World War II era, it’s a lot older than that, reaching back to the “California Cut-Downs” of the late 1920s and 1930s.

Hugely popular in the late 1940s and into the 1950s, the bobber style fell somewhat out of favor for a few decades (thanks in large measure to the emergence of the chopper). However, it’s been making a steady comeback as more and more riders, tired of cookie-cutter sport bikes and cruisers, look to the classics for inspiration.

Like a café motorcycle, a bobber is defined by its owner/builder. Although bobbers have some universally accepted visual cues, like the bobbed rear fender and custom exhaust, the final look is up to the owner, not a designer at a factory. There’s no right or wrong to a bobber, just individual interpretation.

Getting started

So if the bobber’s a returning or “retro” classic, what better motorcycle to bob than the bike that has come to define the retro motorcycle category, the Triumph Bonneville? Our thoughts exactly, and that’s how we’ve come to have a brand new Triumph Bonneville sitting in the MC garage, a scant 7/10s of a mile showing on its odometer.

We’ve started disassembling our Bonnie, and for guys used to working on vintage iron, this new stuff is a revelation. Take the headlamp wiring harness. On the average 40-odd-year-old bike, you’ll spend a solid half hour or so identifying and tagging individual wires to ensure you hook ’em all back up correctly. On the Bonneville, every cluster of wires (except, interestingly, the turn signal wires) has a unique connector, making it impossible to inadvertently hook up the horn to the turn signal or vice versa.

As our Bonnie’s fuel-injected, we didn’t have to worry about slopping gas all over when we removed the tank. Once the seat’s off, simply remove two bolts holding the tank at the rear, slip off a few vacuum hoses, disconnect the fuel pump electrical connection, locate the high-pressure fuel line from the tank to the throttle-body injection units (they’re disguised to look like standard Keihin carbs — very cool), slip its locking clip back while squeezing the sides of the junction and voilà, the line pops right off, with minimal spillage.

Removing the exhaust system, something many Bonneville owners will do in the quest for more oomph and a throatier exhaust note, was no more difficult than on any other bike, although the right rear header pipe mount requires removing the rear brake pedal/foot peg assembly to get to the bolt holding the pipe to the frame.

So far, we’re finding the Triumph remarkably easy to work on. There’s a minimum of extraneous fittings, making the bike ideal for the DIYer or anyone wanting a new bike with old-school styling cues they can customize to their own tastes, just as we’re doing with our Bonneville Build.

We’ll have a lot more to show you next issue when we’ll have our paint scheme and exhaust and suspension changes nailed down. In the meantime, look for us at the Heart of America Motorcycle Enthusiasts Bike Show and Rally and the Road America Vintage Motorcycle Classic to get a sneak peak at the Motorcycle Classics/Dairyland Cycle Insurance Bonneville Build! MC 

Motorcycle Classics Magazine
Motorcycle Classics Magazine
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