[Curt]

It's not about the air in the lines! (That would cause you trouble disengaging the clutch). It's about the clutch itself (it is slipping). You need to change your clutch disks. When you bleed the clutch it stopped because the clutch disks cooled while you where working on that.

I'm no expert, especially with motorcycles, but here's my two cents. Feel free to ignore it if you think I'm an idiot.

My old Camry had a hydraulic clutch. The way it worked was that pressing the pedal pushed the piston in the clutch master cylinder, which increased the pressure in the line going to the transmission, and pushed the piston at the transmission, which pushed a lever that disengaged the clutch. The only time the system ever failed was when the clutch master cylinder wore out ($50 for a rebuilt one). The symptom was that I was low on clutch fluid. I filled it up, and two days later I was low again. I replaced the clutch master cylinder and that fixed it perfectly.

A hole in the line should cause you to leak fluid, and that should make the clutch always engaged (grabbing). Your problem is that the clutch is slipping.

I agree with Bulinu. The clutch plates are slipping. The two possibilities are that either the plates are worn too thin, or else they aren't getting the chance to rub against each other. If there is any way to adjust the position of the plates (perhaps by adjusting the clutch handle or somewhere else), I would sure go for that first. But I suspect that your clutch plates are worn out and need replacement. It's a big job, but not an impossible one.

I think Freakinout's idea about oil won't work. But if you're due for an oil change anyway, it can't hurt. And it's a lot easier and cheaper than replacing the clutch, so what the heck, eh?
Curt