The Excelsior OHC Project

January 26, 2007 8:27 AM

One day, a vintage motorcycle restorer gets an idea in his head to tackle a new project, restoring an old-timey "board-tracker" bike. In and of itself, that's not such a big deal; over the past century, vehicle restoration has become equal parts hobby, business, and spectator sport. The catch with this particular project, however, is that there are no existing examples of the bike he wants to rebuild, the last known extant part remaining is a corroded engine case, and there are only 5 known photographs - all of which happen to show just the right side of the bike. This is the story (so far) of Paul Brodie's Excelsior OHC. [via]
posted by the painkiller (14 comments total)

Master fabricators like this guy are endlessly amazing to me. Great story, thanks for posting.
posted by saladin at 9:04 AM on January 26, 2007

I love this stuff. Even tho' it does make me feel unskilled and inadequate.
posted by cairnish at 10:42 AM on January 26, 2007

This is an excellent post. Fascinating. I wish I knew half of what this guy knows how to do.

At one point early, he says, "Remember, when this bike was made, welding wasn't even invented."

Does anyone know how bike frames were made before they were welded? I've never looked closely at a really old frame.
posted by OmieWise at 11:02 AM on January 26, 2007

The mind boggles at this man's skill. And his dedication.
I'm with cairnish on this.
posted by Cennad at 11:09 AM on January 26, 2007

OmieWise, bicycle frames were built using a technique akin to soldering called Brazing - here's a blog post about bicycle construction techniques. (Rivendell bikes are still made this way, actually.) I would assume motorcycle frames of this era were constructed in a similar way.
posted by the painkiller at 11:20 AM on January 26, 2007

Heck, my mid-fifties BSA still has a brazed frame. On some machines, cars, bikes, and bicycles, the high-strength alloys of the day (Reynolds 531, for exapmle) would bcome brittle and fail at the high temperatures involved in welding, but could be and were brazed.
posted by maxwelton at 11:29 AM on January 26, 2007

Jeebus, nice typos in my comment. I take back my "29" "intelligence" result.
posted by maxwelton at 11:30 AM on January 26, 2007

Very cool, but I wish he hadn't told us about using Bondo on the original case. There has to be a better way.
posted by skyscraper at 12:21 PM on January 26, 2007

Duct tape?
posted by LordSludge at 12:47 PM on January 26, 2007

OmieWise writes "At one point early, he says, 'Remember, when this bike was made, welding wasn't even invented.'"

I think he's using a very specific definition of welding (maybe he means TIG?). Welding has been around since at least the middle ages. Arc and resistance welding was developed in the 1880s and gas welding with acetylene was already becoming popular before the beginning of WWI. MIG predates the war too but I can't remember if was in popular use yet.
posted by Mitheral at 1:49 PM on January 26, 2007

Random side note: I took welding shop in high school, and could never get the hand of brazing; I would often pop the liquid metal pool with the tip of the tool, and the resulting little balls of liquid metal that flew out of the pool would land on my sweater and burn little holes through it, ringed in metal.
posted by davejay at 1:59 PM on January 26, 2007

He's also really impressed with the roller rockers. Many engines of that vintage and even into the 50's had roller rockers because material science hadn't developed enough to use sliders. The cam lobes wouldn't be hard enough for the available lubricants and would fail.
posted by Mitheral at 5:15 PM on January 26, 2007

Jeebus, nice typos in my comment. I take back my "29" "intelligence" result.

Yeh, I bet you kept clicking answer B when you meant C.

Other than that, fascinating post. I know a couple of people who have these kinds of skills & approaches to things, and am sure they are gonna absolutely *love* this story!
posted by UbuRoivas at 8:11 PM on January 26, 2007

It's always interesting to see how craftsman type thinking works, and this is a classic example of a project getting too big for its craftsman, and changing his ideas of what he's trying to do, as he goes along. First, he starts out to make a replica of a rare bike from 1919, working from an admitted paucity of information and extant parts and patterns. As he goes along, he begins using late 20th century tools and technology, and they pull him away from authenticity in his result, but he adapts his purpose to making something that looks original on the outside, but is modern and easy to maintain on the inside. Yet the running gear, including important things like the tires and frame, are pretty straight from 1919, and will, presumably, be bearing loads from a much more powerful semi-modern engine, and none too happily, I bet, if he gets enthusiastic with the throttle.

This thing is neither fish nor fowl. It will, he thinks, have 5 to 6 times the horsepower of its 1919 inspiration, yet the frame, chain, and tires suitable for that older, slower era. Because it will have a modern piston, and quasi-modern head material, it sure won't sound like the original must have, and if it runs modern gasoline and oil, it won't smell like the 1919 version, either. So, at best, it might fool the eye, but it won't likely fool, or inform, the ear or the nose. The beveled gear valve drive, which is a defining characteristic of this design, combined with his roller equipped rockers are expensive oddities, long abandoned for the problems that come with such designs. And yet he continues, in AutoCad, to be able to work with distant confederates in modern ways, to make something he hopes will be unique and desireable. But if he succeeds, it will say "Exclesior" on its side, and nowhere, it seems, even bear his own name.

Still, I hope he gets his running model, and takes it for a careful, grinning turn around some track, if only because while it largely fails as a replica, it succeeds as a Grand Obsession, and this world can always use another Don Quixote.
posted by paulsc at 12:24 AM on January 27, 2007