Need Electrical help!

[catsy]

im preparing my old bike for sale, its a GSX 250 and ive never had a problem with it,
i hadnt used it in a while ( no more then a month) but for the sale i thought id replace the battery.
when i did, the negative lead sparked heavily, then literally caught on fire.

what do you think this means?
any help would be great

 

[hillsy]

Did you connect the terminals on the new battery the wrong way round?

 

[catsy]

Nooooo

 

[Bert Jan]

Nooooo

Nooo as in 'falling of a skyscraper NOOOOOOO'?

 

[Hoosier Daddy]

Sure sounds like it to me... Don't assume the position of the terminals is the same as what you removed. Sometimes the only difference in a battery is the positive and negative terminal location is swapped.