Ignition fure blows after a while

Hello,
I picked up a nice 82 CSR1000 with 2,550 miles on it! It was running fine until recently, now the ignition fuse blows after it runs 5 minutes or so, sometimes longer. Everything is stock as far as I know. I haven't torn anything apart yet because I'm really busy with a building project right now and I just don't have time. A friend said he had an older LTD1000 and had to replace the coils because they shorted when they warmed up. It sounds feasible because the fuse doesn't blow right away so the time delay indicates a high draw but not a short. (I've been an EE tech for 25 yrs so I have some experience how things like this work).
Anyone had similar problems?
thanks Guys!

I had 3 or 4 blow on a ride one day. Met up with a group, go to leave and I've got no power. Find it's the fuse, replace and I'm on my way. Next stop it blows again.
Turned out to be one of the white plugs in the headlight had one wire comming out the back side a little, and it would ground out on the headlight shell when I turned the handle bars all the way to one side or the other. I wrapped the plug with electrical tape, and was fine for the rest of the day.

I'll check that, you never know, Sometimes it just goes while driving straight. I do have access to a DC current loop probe. I can "sniff out" which wire the current is traveling down so I can pinpoint the culprit. As I said I'm swamped with work work and then my building project too.
I need to re-jet for the 4-1 header also, they're getting blue fast. Have you ever tried the Dynojet kits?
Thanks!