How long does a motorcycle battery usually have to sit w/out being used (not starting the bike) before it goes dead?

By the time that I get back it will be almost 3 weeks that I have started my motorcycle, and I'm concerned that I will have a dead battery by the time I get back (early next week).

Also, does it hurt to leave the gas on for 3 weeks without being started? I totally forgot to turn it off! I had an old dirtbike that would flood if I left the gas on too long without using it. Hope the same doesn't happen with my Harley bc the first thing I will do when i get back is go for a cruise... hopefully!

Thanks

 

First post here, I have a bit of experiance in the battery field. As long as your battery is in good condition you should not have a dead battery after just three weeks. I plug my battery tender in whenever my bikes sit just to keep the batteries in top condition.
It does not hurt them to leave them plugged in with either the battery tender or battery minder, they will not over charge.
As far as leaving your gas on, I would think as long as your float level is good you shold be ok.

 

The battery could be a problem if it is old and the weather is cold. Jump it from you car/truck if you have to get right out and ride.Don't sweat the gas thing. I never turn my petcock off. The new ones don't seem to leak.

 

It varies a lot from one bike to the next. The OL's '05 Lowrider has a security system thatdrains the battery too low to start in about 4 weeks. The longest my Nighttrain has had to sit is 6 weeks and it fired right up, but it has a different security system and a bigger battery.

As for the petcock, it's best to turn it off, especially in warm weather. As the gas evaporates in the floatbowl, it leaves behind a reddish powdery resedue that can cause problems. If the bike sits long enough with the gas on, it can evaporate a whole tank of gas and fill the floatbowl with leftover junk. When you park, if you know the bike will sit for a while, it's a good idea to close the petcock and run the engine out of gas.

 

Thanks everyone who posted. It's not cold in Texas (80's) so while the battery may be ok, I hope I don't have carb problems from not draining the gas!