This AWESOME-looking Velorex 562 sidecar soon will be mine (assuming all goes as well as it has so far.) I’m buying it from an incredibly nice, extraordinarily careful fellow named Larry in Bend, Oregon.



Oh, man, I’m excited.

See photo on Flickr.

After a year under a tarp in a driveway, my 1977 BMW motorcycle is (very Germanically) requiring me to prove my dedication before permitting me to ride to the train station in the morning. Now that the brakes are sorted, the headlight is acting odd. There are two switches that drive the headlights; one that allows you to turn the headlight on or off during the day; another to select the high/low/passing beam. Different combinations of switches provide different, puzzling (and very much not standard) results; it’s like a game of Mastermind with accidental blasts on the horn to liven things up. And, sometimes, blue sparks when I short things.

Fortunately, the Airheads list continues to be a fount of wisdom from people who see Airhead wiring diagrams on the backs of their eyelids when they go to sleep at night, and they’ve been giving me plenty of advice. For example, an airhead named Joe ‘Cuda says:

>> It’s dirt simple. Juice (+) comes from the battery via a Red wire to the Relay 30, out Relay 87 via a Yellow/White wire to the switch, to the headlight via a Yellow (Low) or White (High) wire, and then to ground via a Brown wire.

While that doesn’t really fit my description of “dirt simple”, the instructions I’ve been getting have been helping me to sort out the electrical connections. It’s a definite contrast to pushing pixels for a living: while it may look like a rat’s nest inside the headlight shell at first, it resolves to a rational (if complex) system of color-coded wires, each bit of which can be individually checked with a multimeter. So I think I’ve got it narrowed down to a bad headlight relay, which means another call to the Amazon of BMW parts.



Update: Just to fully illustrate the detailed, descriptive, and entertaining nature of the help the Airheads provide, here’s the response I got this morning from “Airhead John”:

Nice photos! I can see what you were talking about. In the first photo the headlight shell looks quite clean and the wiring and fuses look to be in good condition.

In the second photo I agree that the mystery wires are going to the turn signals. Rather than fuses, it looks like 2 into 1 connections. I imagine a previous owner (we’ll call him Sparky) put on an ugly fairing of some sort and spliced into the stock turn signal wires to hook up the fairing turn signals. When the next owner (we’ll call him Rico Suavay) bought the bike he wanted the wind blowing through his hair, so he took off Sparky’s ugly fairing and stuffed the turn signal extensions into the headlight. You don’t need that stuff. I would return it to stock. It appears Sparky snipped off the spade connectors on the blue/red and blue/black turn signal wires and crimped on his yellow bodges. If you leave it like you found it, it
won’t hurt anything (except my feelings).

In the third photo, the yellow/white (gelb/weiss) wire should be getting power with the ignition on. It supplies the headlight switch. Although the headlight relay and all the connections look quite clean, they do fail after a few decades. I concur with your diagnosis of a faulty headlight relay.

Good work.

I swear, can you imagine getting this much and this quality of help in other aspects of life?

I’m taking my 1977 BMW R100/7 out of mothballs this year. And, by “mothballs”, I mean “sitting outdoors under a tarp for a year”, which is the motorcyclists’ equivalent of starving your dog. However, having a baby seems to be the one circumstance when this kind of behavior is forgiven — once. As long as I do some good, solid wrenching on my bike in the next couple of months, the Airheads might let me off Double Secret Bike-Poser Probation.

After a year outdoors, the brake lever pulled all the way back to the handlebar, which is a bad thing. Topping the reservoir up with fluid didn’t help. When I got the tank off to have a look at the master cylinder, I saw that the piston end was weeping brake fluid. Brake fluid is nasty, corrosive stuff, and you want all of it INSIDE the cylinder where it doesn’t eat your paint. And, you know, where it can help stop the bike and stuff.

So I ordered a rebuild kit from Bob’s BMW, and while I was waiting for it to arrive, checked out the instructions for rebuilding the cylinder in my Haynes workshop manual. I found this:
What the hell is this? What kind of workshop manual gives you detailed instructions for removing the part, then rapidly runs the white flag up the pole? Note that this activity is flagged with three out of five wrenches. Apparently, four of five wrenches means “summon NASA”, and five wrenches means “bury the bike and hope that future civilizations with superior technology possess the means to fix it.”

Also note the helpful advice at the end: “Make sure that you buy the right size of cylinder!” Yeah, THANKS for that parting shot. “Make there are no thunderstorms in the area when you dial the phone!” I wonder how many wrenches Haynes would assign to the act of opening the box the new cylinder comes in. “Have an adult help you open the box; paper can give nasty cuts!”

Not that I think I can do everything on my bike. Lubing the drivetrain splines seems to be the wrenchers’ equivalent of crossing the equator for the first time, and my cheeks are still innocent of tar. I’m still in the “change the oil and poke fearfully at the fork seals” stage. But I’ll be damned if I’m gonna let some half-assed limey teabag how-to book command me to meekly submit my cylinder to Yuppie Central for an overhaul (the waiting room of the Devon BMW dealership is filled with lean, rapacious-looking lawyers checking out the new BMW models. Lean, rapacious-looking lawyers that, like me, do not know how to lube their drivetrain splines.) Hey, books can tell us how to knot a bow tie, right? How hard can this be?

Kate’s dad Bob pointed out that Haynes is notorious for simply reprinting the text of the original owner’s manuals delivered with the bike. Fortunately, my Clymer manual, which is easily five times the thickness, displayed no such dithering in the face of the enemy. In fact, I’m pretty sure you could assemble a space shuttle from a Clymer book.

So I got the piston out and had a look. There was some weird clear plastic wrapped around the piston body, which is a bit of a mystery. Fortunately, any problems with the old piston were moot, as the rebuild kit contained a new piston in a cheerful shade of anodyzed green, and a couple of rubber seals that require some kind of three-armed proprietary BMW assembly awl to stretch over the rings in the piston and put in place. I used fingernails and loud profanity, and shot the rubber rings across the garage several times (lose a single ring, and your spiffy fifty-dollar rebuild kit is now a collection of funny-looking table shims), but finally managed to get everything together. Whew!

Here’s a picture of the piston that I took and posted to Flickr, in hopes that some wise member of the Airheads community would know what the mystery-plastic was in there. So far, about a hundred views, but nobody wants to offer an opinion. Hmm, maybe Haynes was trying to shield me from a terrible secret.