At Last...

So, a month later, I seem at last to have mended my motorcycle.  An engine needs three things: air, gas, and spark.  I determined it was getting gas by pulling the fuel line off the hose and sucking on the vent line.  Gas came out.  Then I determined it was getting to the carb by opening the float bowl valve.  Gas came out.

Then I figured out it had compression because when I tried bump starting it slowed and grabbed when I popped the clutch.  But it still didn't start.  And that just left the problem of spark.

I left the spark for last because it meant that I had to pull the body of the bike apart to test it.  And it turned out to be the problem indeed.  I pulled the sparkplug out and put it back in the boot, then grounded it on the engine and hit the starter.  No spark.

First I thought it was the plug, but when I replaced that it still didn't work.  Then I thought it was the coil, but I bought a cheap multimeter and tried to test it, and it seemed to be good.  Then I decided to follow the wiring back from there.  What a mess.  I cut all of the wrapping off the wiring harness.  It took days.  I found  a wiring diagram online, but it wasn't accurate.  I only found that out after following every wire there was.

I got kind of hung up on the start button, and cut it up.  Then I realized it was actually fine, and had to go back and solder it all back together.  Seriously this was all a tremendous amount of work.  And I was working on it all the time.

After I figured out it wasn't the ignition switch I thought it was the starter relay.  I tested that though, powering it with a 9volt battery.  It clicked fine.  Then I thought it was the ignitor.  There wasn't really any good way to test it.  I was really hoping it wasn't that.  It's the most expensive part in the electrical system.  $175.  The coil isn't much cheaper.

Then I followed the wiring back from the ignitor, and thought it was the fan switch.  It wasn't.  Then I thought it was the kick stand sensor.  It wasn't.  Then I thought it was the pulsing coil.  That would have been a real mess, because I'd have had to pull the engine case apart, take off the cam chain and gears and get in behind them.  Happily I tested it at the connector and it was ok.  I checked the battery, but I was pretty sure that was ok, since I'd replaced it only a few months ago.  It actually had run down from all the testing I'd been doing without running it.  So I charged it.  Then I was back to the wiring.  Then when the wiring checked out, I was back to the coil.

I got a copy of the factory service manual, and ran some more detailed tests on the coil.  The secondary coil seemed to be ok, but the primary failed.  This wasn't a good thing because the coil costs about $125.  So I took it to the parts place, hoping they could test it better than I could.  Like I said, my multimeter was pretty cheap.

When I took it to the parts place the guy who helped me took the sparkplug boot off and looked at the lead.  There was no visible wire in the lead.  Turns out that's the bad thing.  I'd have never known it, but the leads deteriorate.  So they sold me a splitter and a little bit more lead.  I took it home, put the gas tank back on, and it fired right up.  Huzzah.

Now I've just got to put it all back together.  The problem is that it's been a month.  I don't really remember how everything fits exactly, and fumbling around the garage for a month I've bumped bits and pieces and knocked out bolts and nuts.  The result is...  we'll see.