search for manual and check schematic. there's one here somewhere.

Thanks, but I have a printed manual
What I was trying to ask is: which parts of the bike should I investigate first, given the symptoms?

Currently my plan is as follows:
1) Check if the main switch fuse is not toast
2) Check if the ignition lock works, by poking in its connector plug with a multimeter.

Any other suggestions?

What? You know the ignition switch is bad, so when it possibly finally died you ask for advice. Here's some replace the damn switch And check your fuses including the fuses on the starter relay.

Well, that's just the thing - I don't know for sure if it's the switch or something else I mean, the switch was kinda bad MECHANICALLY (like I said, I always had to wiggle the key around a bit to be able to turn it), but there were never any electrical issues with it - when the key turned into the ON position, there was always power.

But I see your point - the main fuse, battery and ignition switch are the primary suspects, that's for sure.

If the switch was always kinda "funky" then it is bad and needs repair or replace.

Listen to the Katvets and replace the ignition switch. then go from there.

There is a reason they are here.

There's also a reason why ZukiFred's post count is so high. He knows his stuff. So does 92xjunker.

Good rule for narrowing down problems is to fix the known issues to get to the unknown not visa versa.

OK guys, I actually managed to get it working.
So I was prepared to try taking the ignition switch off the bike, but I thought that I might as well try cleaning it while I take the fairings off and check the main switch fuse. So, I blew some WD-40 in there and let it soak while I was checking the main fuse (which turned out to be perfectly OK). Then I took a can of duster gas, blew the excess WD-40 out of the switch, and a TON of dirt and muck came out with it! I was a little surprised, because the previous owner took really good care of the bike, so something as sloppy as a dirty ignition lock was completely unexpected. Still, I feel kinda dumb...

Now the ignition works just fine, and the mechanical "funkyness" also seems to be completely gone. Since I've read somewhere around here that WD-40 will probably collect dirt inside the switch, I'm thinking about washing it out with some brake cleaner and lubricating the lock with graphite powder after it dries off. Am I thinking in the right direction here?

Anyway, thank you very much for your help!
Sorry I started this mess over such a tiny problem

That said, the next time I take the bike apart to repair or install something, I think I'll take a closer look at that ignition switch, just to be sure that it was only the dirt causing those issues.

Yeah, you're right... I guess I'm still too young, hot-headed and stupid for that kind of rationalism - wisdom comes with age

Sorry for double-posting, but it turned out that the problem didn't go away after all.
A couple of days ago my bike stalled when I was on my way to work, and I couldn't get it running again. This time, however, I noticed that the clock was also dead, and so I thought that the ignition switch probably wasn't the cause of the problem, since the clock is not controlled by the key.
Another funny thing was that the bike was alive again, when I got back to it after work.
Anyway, there was definitely a weird electrical gremlin somewhere, so I decided to try and find as many suspicious places in the harness as I could, fix them up, and hope that one of them would do the trick.

So here's what I did:

1) Checked the battery, which turned out to be OK - 12.6 volts w/o load, 11.9 volts when starting the engine.

2) Checked the fuses - OK.

3) Checked the continuity of all positive and ground connections that I could
reach, especially the ones near the "bottlenecks" - battery, fuse box, starter relay. Nothing suspicious, even when wiggling the wires around - no abnormal resistances, no continuity breaks.

4) Took the 4-pin power connector off the starter relay, and saw that the positive contacts (there are 2 of them there, in parallel) are in really bad shape - heavily corroded and nearly breaking apart. I fixed that by cleaning the oxidation off, soldering a small copper plate onto the good part of the connector and dremelling a new set of contacts out of it.

5) Inspected every other plug of the harness that I could reach, cleaned them with duster gas, sprayed with contact cleaner, let dry, reassembled.

6) I also took the ignition switch apart for inspection. Fortunately, the Torx bolts that secure the lock to the traverse came out very easily, because the loctite on them turned to dust from old age. The lock cylinder was OK, so I simply cleaned it with kerosene and duster gas, and re-lubed it. Reaching the contact group of the lock was, however, kinda tricky: the lower lid was secured to the casing with something that I first mistook for rivets (see pic below). After dremeling those out (breaking 3 bits and cutting my hand in the process), they turned out to be screws with unslotted heads (WTF?). Replaced them with some regular M4 screws later. The contacts were actually in very good shape - relatively clean, not worn. Cleaned and re-lubed them, and after that re-assembled the lock and checked it with a multimeter (OK).

So anyway, I'm not sure if I fixed the initial problem of the bike's electrics randomly dying, but at least I cleaned some rusted plugs, made a new power contact on the starter relay, and found out that my ignition switch is OK. I guess I'll have to assume that it's fixed for now, and search further only if the problem re-emerges again.

Here's a pic of those unslotted screws that were holding the contact casing of the ignition switch:

Do you know where you can buy the "4-pin power connector" you referenced in step #4?

I am having a hard time finding a coupling that would fit on my relay.
http://www.ebay.com/itm/Starter-Rela...78ff3f&vxp=mtr

^^ this is what I'm working with, and I have a feeling I am missing some wires to plug into the solenoid/relay. My bike was purchased not running.

Sorry I'm answering so late, haven't checked this forum for a while. Anyway, I'm afraid I can't help you If I knew where to buy that connector separately, I'd have changed mine too. I think, if I were you, I'd simply McGuyver a solution by using some other 4-pin connector and doing some minor soldering.

Or, even, forget the connector and solder 4 wires directly to the pins of the relay, and cover that place with something waterproof (silicone?). Sure, that way it won't be as serviceable as a connector, but at least it will be solid.

the slot less screws are anti tamper to prevent theft. cars have them too.