Why does my motorbike keep cutting out when i put it in gear?

Answer

Does it have a safety "kick stand" switch?
It a wire grounding when you sit on it?
Loose coil wire?

Does it cut out no matter what position the throttle is in? In other Words, will it stay alive if you pull in the clutch, keep the revs of the bike up, then click it into gear?

If so, this might be a clutch issue, such as a grooved clutch basket not allowing the plates to separate enough. An easy fix, if you know your way around an engine. If not, I suggest taking it to the dealer. Otherwise, try the easy fixes first, play around with the barrel adjusters on your clutch lever and see if it goes away. If it's cold outside when this happens, try running a slightly thinner transmission oil to keep the clutch pack from sticking together.