So, I got the boxer to run on my first try, but it clearly wasn’t running properly and would hardly take any throttle. I was thinking maybe the ignition timing is off, better check that. A strobo-lamp attached to the spark plug wire soon told it’s clear tale: igninition timing seemed to be in spec, but more alarmingly the right side spark plug wasn’t firing at all. I knew the suspect, I had been warned before: the ignition coils of the 1990 GS’s were prone to crack, and will cause problems when wet, or start to fail in other ways. They should be replaced with later improved coil models from BMW. As they OEM’s aren’t exactly cheap, I decided to order a used later design model off eBay Deutschland, and try with that. At the same time, I’ll replace the spark wires, plug caps, too. I have all the parts now, but have lacked time and energy to finish up with the installation and re-run. Busy work and now a flu have kept me outside the garage.
The Boxer is alive, fire breathing son of a gun again!
Battery charged, some oldish fuel added in the new G/S tank for appetite, ignition switch attached, and then a very careful turn of the key… Ignition lights are on!
Apply some choke, thumb on the starter button – what’s going to happen I wonder, it’s been nine months since the last time it ran.
Press on the button, and this:
Some assembly required, they say. A motorcycle of airhead caliber is pretty simple machine actually, but assembling it takes hours after hours of small and big screws, washers, zip ties, cables. Actually trying to find all the right little bits, at a right time, and to fit into right place – I should have been a lot more methodical at disassembly!
Cylinder stud repaired, new gaskets all around, cleaned and valves lapped, carbs rebuilt as well – and now thrown together to 1/2 of an airhead. Oh, new spark plugs too, and just noticed I’ll be needing a new coil, the old one has a cracked cover, typical for the original piece, resulting in cutouts in rain.
Heads up (or sideways rather!) for an upcoming pictorial and a short documentation of a small Airhead motorcycle build I’m working on. Part stripped, part painted, it’s all coming along slowly.