Long time no post!  Hope everyone is happy and healthy.

The topic subject pretty much says it all, I think. My 2002 GS has been sitting for a few months outside, and when it came time to throw the battery into it and bring it to a friend's place for the winter I found it wouldn't start.  I tried bump starting it, but after a few tries the bike really started having trouble rolling while in gear (but with the clutch level pulled in).

Any suggestions, aside from buying a new battery? I was hoping to wait until Spring for that.

Thanks, guys.

Cay

Wet clutch + cold oil = drag = difficulty rolling bike in gear with the clutch in.

Step by step.  Check the voltage on your battery.  If it's low, put it on a trickle charger until it's happy, and try again.  It's going to be hard to start if it's been sitting; consider draining the old gas out of the tank and carbs, then filling the tank with fresh gas and trying a new start on Prime.

Try bump starting in 2nd gear, it is easier.

Hmm.

The battery had been inside and on a charger for a few weeks prior and I tried bump starting it first in second, then a wide assortment of gears. There's enough juice to bring the headlights up and to turn the engine over a tiny amount, but that's it.

It probably doesn't help that there's old, summer gas in it either.

1)  Keep bike switched OFF to retain any small amount of power the battery may have until you can...
2)  Start moving at speed with bike (ideally moving down a hill, in NUETRAL)
3)  Slip into 2nd gear when momentum is there and pop it quickly...when bike starts, full choke and keep it up til it's ticking over nicely...
4)  Sorted....!  (now ride and buy a new battery  )

out of interest how 'bad' is bump starting the bike?

had to bump mine a few times prior to buying a new battery, and I remember I had to keep it on full choke once it was going for quite a while. Can't be healthy running a cold engine at 3000 RPM from the off for several minutes can it? Aside from the engine, any other parts of the bike affected?

I've had to bump start mine, and it starts and runs as normal, you should be able to bump it then back off the choke and idle around 1500-2000 while warming up.

How is it not starting? Is it turning? Is it whining low?

Check the play in the clutch. Maybe it's out of adjustment and not disengaging the clutch all the way.