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MC How-To

Step by step: From general maintenance to complete restorations, we share tips and tricks for working on classic bikes.


Real Life Wrenching: Triumph Bonneville Restoration Update

Editor's note: This blog was originally posted in October 2010 in the Real Life Wrenching blog at MotorcycleClassics.com. 

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Me and my 1972 Triumph Bonneville. 

In 2010, my father, an avid Triumph enthusiast, finally gave me one of his prized motorcycles. However, he wasn’t about to let me ride off on a running, restored vintage Triumph. If I was going to have one of his bikes, by God, I was going to learn something and build it myself (such a Dad move!). So I packed the entire bike, a 1972 Triumph T120 basket case, into my compact car and drove it home in boxes. 

Four months later, I’ve spent every weekend and evening possible wrenching away at my restoration project, trying to get to the next step. I have to admit, it’s becoming one of the most addicting hobbies I’ve ever had. As a newcomer to the world of motorcycle restoration – or bike mechanics at all, for that matter – delving into a project like this hasn’t exactly been easy, although I can’t say it’s been all that difficult, either. It’s time-consuming, expensive, at times frustrating, and generally slow going, but it’s always rewarding. And I’m barely halfway there. I’ve said it a million times already, but I know I’ll shed a tear when I finally fire her up.

My first order of business was to get the chassis together and rolling. The frame had already been powder-coated, so the wheels came first. If you’ve restored a bike before, you have to know how valuable a bead-blaster and polishing wheel can be. And in mid-summer, polishing aluminum gets really hot, really fast. But it works after you’ve slaved away for hours, and the hubs cleaned up beautifully. One of the original rims I cleaned up and saved, the other I replaced, and then, to many a furrowed eyebrow, laced and trued my wheels. Knowing how mission-critical wheels are, I decided to take them to an expert to fine-tune them in the end, but got to go through the whole process quite successfully, nonetheless. Then, I installed the bearings, put on new tires, reassembled the disc breaks, and poof! My wheels were done. (This step took me at least two months.)

Then, it was on to rebuilding the forks. I decided to powder-coat the fork stems for more of a café-look and to get around the fact that they were looking pretty grimy, and I’m quite happy with the end result. In the beginning, the plan was to go completely original, but I am making this bike for me, so I’m taking some creative license without sacrificing the soul of the bike’s original form. The forks were simple enough to rebuild again, with highly recommended Progressive fork springs and new tubes. Installing them into the triple tree was another matter all together. We “encouraged” them to go in with some gentle force, lots of WD-40 and the help of a friendly local police officer who likes to take “breaks” by stopping by the garage to hang out with the bikes. It turns out, cops do more than protect and serve from time to time! At the end of the day, I had my rolling chassis complete, and a big fat smile on my face.

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The rolling chassis, complete with temporary handlebars. 

It was easy to focus on the wheels and forks, because the goal was clear. Now that this first step was done, I found myself with a whole lot of options for what to do next. This is where I started to get a bit ADD. However, it’s nice to jump from one thing to the next just to keep it fresh sometimes, so here and there I rebuilt my carburetors, installed some temporary handlebars so I could push the chassis around without dumping it, rebuilt the air filter system, and obtained a replacement headlamp. When the chrome goes, sometimes it’s pointless to try and salvage the part – just go aftermarket.

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Amal carburetors, before and after rebuilding and polishing. 

Now, I’m on to the wiring, which reminds me a lot of the truing process. It’s not all that cut and dry by any means, but if you just go one step at a time, take enough breathers, and Zen out to the process a little, you can make a lot of progress. Just don’t over-complicate things, as complicated as they may seem at first glance. One trick that helped me was to mark wires with tape and a sharpie so I wouldn’t have to go back to the wiring diagram every two seconds. This helped immensely. The Bonneville’s electric system isn’t too terribly complicated, though, so once you figure out where one wire goes, that’s one less you have to figure out. One by one. I should have my lights and indicators all working soon, with a little luck and patience. 

The big hurdle in front of me now is the engine, which I will be assembling myself. Did I mention I am not a mechanic? This should be interesting. Machining and some other mission-critical aspects of the engine I’ll farm out to an expert, but I want my hands on every part of this rebuild and restoration as humanly possible. In the end, it will really be MY motorcycle, and I will have earned her whole-heartedly.

Four months have gone by, and even though it seems like a mountain of work (and money) still lies ahead of me, I’m making pretty good progress. It would be nice to have more time, but alas, I couldn’t afford all the parts I’ve bought along the way if I didn’t have a full-time job, so I’m left with the weekends. The original goal was to have the entire project complete by next summer. Since I think I’m making good time, I’ve pushed my goal up to March so I can enter my first-ever restoration into a local bike show – the Clubman’s All British Show here in San Jose. Who knows, maybe I’ll even win an award! But if I don’t, just getting there will be a big reward in itself. – Jennifer Lankford