I'm prone to insomnia at the best of times. These muggy Summer nights don't help. But I'm also somewhat obsessive about my bikes - if one isn't working it gnaws away at me in the small hours.
Following the 10,000 mile service on my grey bike it was running sweetly and I thought I'd treat it to a bit of TLC. A thorough clean (that doesn't happen often) and a bit of cosmetic tinkering - including re-locating the tacho. And then when I came to fire it up in the evening - nothing. A quick check showed no spark at the plugs. Fuck-ety Fuck Fuck - I hate electrics.
Seat off, tank off, check all connections, spray them all with WD40 - still nothing. Get out the multimeter and the service manual and pretend that I know what I'm doing. There's power getting to the coil but still no spark. Maybe's there's water in the coil from where I washed it. Leave it overnight - but still no spark in the morning. In the evening start looking at replacement coils on ebay. Go to bed - can't sleep.
Then it comes to me. What happened in between it sparking and not sparking ? I'd only been thinking of washing it and the possible introduction of water somewhere it didn't belong. But I'd moved the tacho' too - what if something was wrong there ? It's an electronic item so it is linked into the bike's main circuit - could a short there trip the ignition ? I'd like to say that I checked the wiring diagram but I have to say that I tend to find these as useful as hieroglyphics. But I do remember the Sherlock Holmes axiom though: 'when you eliminate the impossible whatever remains, however improbable, must be the truth'.
So I got up early in the morning. Took the tacho apart. Put it back together. Flicked the starter - and bingo. Fuck yeah - I can't recall being so pleased with myself for a long while... then I remembered that it was my own initial cock up that had caused the problem in the first place.