Nineteen Cents
NINETEEN CENTS
UP FRONT
EDITOR’S LETTER
THE BODGE AND THE UNINTENDED ROADSIDE STOP
I accept a certain level of precariousness when I saddle up on a vintage bike like my ’74 Norton Commando or ’54 Velocette MSS. The chance of not making it is even a little bit of the charm, though I work exceptionally hard to make these old nails reliable and to be prepared for the unintended stop so that it doesn’t last too long.
But I never even consider a breakdown on a modern bike. So when my long-term Yamaha FZ-09 started misfiring ever so slightly midway through a 250-mile ride, I thought maybe it was bad gas.
Or worse, that the Bazzaz Z Fi TC tuner might be acting up since we had to warranty the first $849.95 unit not long after it was installed.
As I rode on, the problem worsened, and I knew there was more going on than bad gas. Once I got back to my home shop, I dug in to see what I might find. As I began to remove the unit and its attendant wiring, I found 3M Scotchlok T-Tap connectors in four places. With these “insulation displacement connectors,” the wire being tapped slides down between blade-like aluminum sides as a cap locks over the top, cutting the insulation and allowing contact with the wire. A spade connector goes in the end and that’s your wire tap. I’m not (completely) singling out Bazzaz here, since most other add-on EFI units use these for many applications.
Here are the problems with this type of connector: It cuts the insulation, making a weak point in the wire; this particular connector type is not sealed (some are), exposing both the copper wire and the aluminum of the connector to the elements and possible corrosion; and the metals in contact are dissimilar, also potentially causing corrosion, resistance, and making the wire more brittle.
The failure here was the connection at the throttle-position sensor, where the strands of wire were cut and began to make for an unreliable signal. When I inspected that connector, I merely tugged lightly to see what was going on, and the wire broke in two. It had been hanging on by mere molecules, and I was lucky I made it home.
I stripped the two pieces of the stock wiring harness back and butt-soldered them together and shrink-tubed and taped the repair. It will be fine for the life of the bike.
I poked around on the Interwebs and found you could buy this exact Scotchlok connector for 19 cents each, or $9.95 for a pack of too. The irony here, of course, is that a connector that cost a few cents included with an $850 fully programmable EFI/traction control/ quickshifter unit almost brought my $8,000 long-term testbike to a halt.
And the bike ran great with the unit. Power was up, and the new map fixed about 90 percent of the off/on throttle abruptness. You could charge a secondgear corner on the bike, hit the apex, and snap open the throttle to exit hard, letting the TC do its work. The FZ-09’s awesome midrange torque would bring the front wheel up, and then you could click a seamless upshift to third gear and carry the wheelie. It is the kind of sporty moment you live for, and the FZ-09 just doesn’t run quite this well on the stock map. But I couldn’t bring myself to use the wire tap again, and permanently soldering in the four tapped harness connections on a long-term testbike is not practical. But that’s what I’d do if the bike were mine.
A bit of precariousness is fun, even expected, on a vintage bike. But we all need something to rely on in life. I am wire-tap-free from here on out, and I bet you 19 cents I’ll never have a problem like this again.
MARK HOYER
THIS MONTH'S STATS
76 CENTS WASTED ON T-TAP CONNECTORS
RESISTANCE FOUND IN THIS BLACK WIRE
too PERCENT RELIABILITY OF ATYPICAL MODERN WIRING HARNESS
