Occasional backfire?

[turbocamino]

Hello FJ brothers,  Once in a great while,at cold start only, my 89 gives a tremendous back fire as soon as i touch the button...maybe one in 50 cold starts....scares the crap out of me!! ...totally unexpected.....afterwards,its starts fine, no smoke nor loaded up at all and runs perfect.The only ignition change has been a V&H advancer....   i'm thinking maybe there must be some unburned fuel in the motor? maybe one or more float(s) sticking? but only cold and very intermittent?.any thoughts appreciated. 

[FJmonkey]

Not sure what is causing it but you could get a ticket for it....

Read Flying Scotsman adventures on starting his bike.

http://www.fjowners.com/index.php?topic=2328.msg19234#msg19234