Shop Class as Soulcraft_ An Inquiry Into the Value of Work - Matthew B. Crawford [46]
This is a common experience, actually, and in an effort to save time in assembling and disassembling things with an inscrutable Oriental fit to them, I used to try to hypnotize myself into a Zen-like state of resignation at the outset. It doesn’t work, not for this Grasshopper. I have my own process, as they say. I call it the motherfucker process.
The cams and rockers looked fine. Beautiful, actually. All four valves on the number 2 cylinder were tight, so I adjusted them to spec: .005 in. By the time I got the valve covers back on, I was seven hours into the bike (this figure is truly embarrassing), with essentially zero progress toward getting it on the road. The tight valves wouldn’t have prevented it from running well enough to get a fuller assessment of the bike. At my shop rate of forty dollars per hour, that would be two hundred eighty dollars, but there was no way I could charge him for seven hours. In any case, I now had less breathing room in dealing with the bike, as far as time and money spent. In retrospect, I should have left the valves alone and focused on stuff that was obviously a problem.
Like the carbs, for example. Getting them sorted required three trips across the river to Bob Eubank’s motorcycle junkyard to scrounge for linkage, then a missing spring, then a carb body. But it is the clutch hydraulics I want to focus on in this story, as they show the moral tension I’d like to describe between a mechanic’s metaphysical responsibility to the machine and his fiduciary responsibility to its owner.
The clutch wouldn’t disengage. I bled the system but couldn’t get all the air out of the lines. Air is compressible, so air in the system prevents the transmission of pressure through the hydraulic lines, which is necessary to move the heavy springs that sandwich the clutch together. So I rebuilt the master cylinder, which really means just disassembling it, cleaning it out thoroughly with solvent and compressed air, removing the glaze on the cylinder by scuffing it lightly with some gray Scotch-Brite, putting in a new piston and seal, and replacing some crush washers.
Still the system wouldn’t bleed. So I removed the slave cylinder as well. The cavity where the slave cylinder mates with the engine case was full of nasty, emulsified goo. I noticed the seal on the back of the slave cylinder was badly deteriorated, and was glad to find the culprit; fluid was obviously leaking out of the slave. Once I’d cleaned all the goo out of the cavity, I noticed that an oil seal in the engine case immediately behind the slave cylinder looked kind of buggered. So I reasoned that the goo was actually a mixture of clutch fluid and motor oil; maybe oil leaking from the motor had caused the slave cylinder seal to deteriorate. Maybe they were different kinds of rubber, each able to withstand only one kind of fluid. I’d never heard any discussion of the issue. In any case, I wanted to replace that oil seal in the case. Like most oil seals, it was shaped like a doughnut. This one was about the size of a quarter. The inner diameter has a little lip that rubs against a rod, wiping oil from it as it moves back and forth through the seal. That rod moves when you squeeze the clutch lever.
Clutch rod oil seal
But here caution was called for. Was the seal held simply by an interference fit in its hole in the engine case, or did it have a step in it that seated against a shoulder machined into the inner face of the case? Try