tomlord2301

ive recently bought a gasgas 280 txt 2000 model and the bike randomly makes a hissing/puffing noise coming from around the electrics/engine area. i cant put my finger on when the bike does it as it can do it 3 times in a minute and then not again for half an hour. I was just wondering if anybody has encountered this problem before and could guide me to what it could possibly be?