I was on an on-ramp coming onto the highway the other day, one of the right-turn-curve ramps getting onto I-70. Going just a little too hot, had to lean WAY down (foot pegs drug the ground, '79 650)... Got down there and felt the bars almost crank to the right (while making a right turn). I know if I would've let the bars go over I would've low-sided it. Is this an indication of losing traction on the front (needing a new tire), or is it an indicator of something wrong with my front-end (fork flex, etc.)?
Not doing much for my grand plan of saving money on gas though... I'm tripling my weekly miles... 
Same here!!
Assuming you were not on the brake... Usually if you wash out the front end from too much lean, the fork will go to lock in the direction you were countersteering. So you should have felt the steering sliding to the left in a right hand lean. Don't ask me how I know... Actually I have a lot of experience, and that's the way it goes.
If the sliding front tire feels like its steering in the direction of the turn, my guess is you're on the brake too hard. If the tire has 25% of tread depth or more, its probably OK. But some tire brands have more natural stick, usually a function of price. Road Racing slicks don't have any tread at all and are very sticky. The cheap knock off tires are fine for everyday use and look great, but may not stick in the extreme. If the fork is not skipping, or chattering, its probably set up OK, though those things are always variables. If the fork was flexing it may also chatter as when it flexes it can't move up and down.
The rear may have been sliding out, that would make the front feel like its turning in. My 67 Bonneville had solid pegs and when they dug in they would lift the rear wheel and down you go. The Jap stuff mostly has folding pegs to avoid this. But you can dig the next thing down like the pipe or the centerstand and lighten the rear end as well. Or again, too much rear brake. And these things can happen on very small levels and you can still feel them. And sometimes, when everything is perfect and done perfect, within human limits, you still crash.
And sometimes things are hard to explain, and I'm no expert, but I have crashed a lot and survived, and the memories are very vivid. Most of my crashes came from target fixation and braking in the turn. I've never hit another vehicle and that's why I'm alive. When we were growing up, there were no MSF courses or Keith Code books or track training like there is now. And I did not have a high natural skill level, just a deire to outdrive what skills I had. I've found that I can overcome my lack of natural skills with training.
