So I changed the spark plugs on my recently purchased 97 F3, and now the bike barely has any power. It idles fine, runs smoothly and doesn't make any unusual noises, it just has about 1/4 of the power it used to.

I redid all of the spark plugs to make sure they were connected solidly. And I'm charging the battery right now.

I'm thinking this is an electrical problem, anybody have any ideas on what to check?

 

It's got to be related to the change of plugs (you would think so anyway), so, did you get the right plugs & are they the right heat setting? (same as the old ones). Did you gap them to the right specs?
Check to see if the caps & leads are secure & are in the right firing order.
Another option would be (if you still have them) is to replace the old plugs & see if that makes a difference. Although new plugs are made well, does not mean that the odd dodgy one gets past quality control.

 

I tried the old plugs, and the problem is still there.

I checked the spark on each plug wire, and cylinders 1 2 and 4 all have strong sparks, but 3 has a weak looking yellowish one, which my Haynes manual says is bad. Could this be the root of the whole problem? I'm going to replace it, but it seems to me like there is some larger problem I haven't found yet.

 

So...this is embarrassing. I switched the plug cables on cylinders 1 and 2.

Off to the twisties!

 

LOL!! There is no shame in making the fix for the problem way harder than it has to be. We're manly men and it's what we do. Case in point:

I once had a lightbulb go out in our shop at work. It was a sealed sodium bulb and because it was 60 feet off the ground it required a man lift and some time to replace. I turn off the breaker, go up, change the bulb, come back down, turn on the breaker, flip the switch, and got nothing. I spent the next 3 hours testing the fuse box, checking my building ground, calling an electrician buddy, cursing at my new problem, etc. Then I noticed that the "old" bulb looked awfully new...

Glad you're up and riding again.

 

 

Or today I was replacing the rear brake caliper holder cause there was a broken bolt in it. So I took off the rear wheel and did a couple other things, like grease everything and clean the chain. Had a bit of trouble getting everything lined up (knocked the spacers out bout 10 times). Got everything on and went to mount the rear caliper but one bolt wouldn't go in cause something was blocking it.

Namely the broken bolt cause I remounted the old one

 

maybe you stripped the threads when screwing the new plugs in?