Need advice about boosting the battery

[Guest]

Hi all. I am going to check one GS450 which is sitting in garage for three years. I was told by owner that he didnt start bike for three years and that battery is not holding power.
Now my question is,
1. Can I start a bike without battery and can bike run without battery?
2. Is it good idea to give it a boost from car battery?
3. Can I try to start it with battery charger being connected to battery while charging?

Is there any chance of damaging any electrical parts on a bike if I use any of these methods? I am sure I cant do any damage if I try to start it without battery being connected to the bike but what about other ideas?
Any other ideas?

[tkent02]

Don't run it without a battery connected. Jumping from a car is OK, but DO NOT run the car engine while the bike is connected to it, expensive parts in the charging system of the bike will burn up.
With the car shut off, it's fine, or a battery charger is fine.

[Inblues]

Thank you tkent02. I will then try to start it from car battery.

[bbytes]

Any bike with an alternator needs a battery. Old, small, dirt bikes used to use a magneto which could keep the ignition going without a battery, but most bikes use an alternator.