First up: cleared stuff out of the way so I could get at the spare engine. Pulled off the cover, removed the clutch pack, put the cover back on and stuck the spare back in its corner.
Adjusted the clutch on the bike, on the off chance that was why it was acting up, but I did it by the book, to the letter...and there was no change in the feel of the thing. Anyway the clutch hooks up solid when I'm in low gears, even accelerating hard; it only slips in high gears when I open the throttle too far.
I'd had to move Mrs. Fungus' bike to get at the spare engine, so I pulled the side cover off and pulled the battery out. I didn't even check it; I just took it out and hooked it to the trickle charger. Then I took the booster pack, connected it to the battery cables, and tried her out...and naturally it cranked for a moment and then VROOM! like it had been running yesterday. Only it hasn't; I don't remember the last time I started it but it has been on the order of a year, and the gasoline in that thing is at least four years old.
Let it warm up a bit, until I could rev it without the choke on. Not bad. I'm going to take it for a spin this weekend to see how she feels.
Then I sat down with the vernier caliper and the manual and the clutch pack from the spare motor, and let me tell you: every last damned bit is well within specification. It doesn't even look like it has any wear on it! The cage itself has got the kind of angular (concentric) wear pattern you expect from a pressure plate, but the driving and driven plates don't look worn at all. I don't know how much is "wet clutch" and how much is me never having seen a motorcycle clutch pack before. I'll know more when I take my bike's clutch pack out this weekend and swap this one in.
What I'm going to do is to hose down the parts with brake cleaner or something to get them clean, then soak them in fresh 10W40, and then install them. You have to drain the bike's oil before you take the side cover off (unless you like having 2.6 liters of oil spilled all over your garage floor) so I'll be changing her oil, too. These parts had a bit of a gritty feel to them, almost as if they'd been sitting in dusty garages for more than ten years.
Anyway, that's nice: I don't need to go buy a clutch rebuild kit because the spare clutch is well within spec, and this will let me see if my slipping clutch really is a worn clutch, or a problem with my understanding of the clutch adjustment procedure written in the advanced engrish in which the bike's manual is written.
"Turn adjusting screw in until significant resistance is felt, then back off 1/4 to 1/2 turn," it says, which sounds perfectly reasonable...but what is "significant resistance"? When you can't turn the screwdriver any more? When it starts to get stiff? And why "1/4 to 1/2 turn"?
It'd be nice if they explained where the pressure point should be. Right now it's close to the end of the clutch lever's travel.
Well--once I've had a chance to examine the clutch that's in the bike and determine how to proceed, and once I've proceeded, then it'll go to a pro for a tune-up. Whee!
Next up: moved the Mustang out of the way--pushing--and swept the floor and tried to neaten things up a bit. I rearranged a bunch of stuff, so now I think I've got a reasonably convenient arrangement of things.
Put the battery in the Mustang, turned the key--absolutely nothing at all. Battery voltage, checked with a DMM, was about ten volts, which is WTF territory considering I just had it on a charger last week. Nobody promised me a rose garden and it's been sitting, mostly unused, since we bought it...and disuse is bad for batteries. That's why they make float chargers.
Hooked the jumper pack up, got a grunt and a click from the starter--so who knows? Maybe this weekend I'll take the battery back out and hook it to the big charger and see how it does.
Tomorrow, they say, not much of a chance of rain, and it'll be partly cloudy and pleasant. I'm thinking I might go ahead and live the dream, and ride my motorcycle to work.