Another one that won't start!!

Hi all, help needed please, i have a 03 plate thundercat that i bought a couple of months ago, 6000 miles, has been superb up to now, yesterday i went for a short blast of around 80 miles and the bike was great, when i got home put it into the garage, connected up to optimiser, today went to go out again and it wont start, turns over and backfired, just found it wierd that yesterday it was perfect, any ideas please?

Check the battery terminals for tightness?

Thanks Weasley, checked battery terminals and all ok, have not had time to do much today, am going to investigate further tomorrow, just seemed strange for something to go wrong whilst sat overnight.

Batteries can just give up the ghost aswell. Check voltage. 
Or is it turning over and not firing up??

battery is kept on optimiser whenever bike is parked up, yeah it is turning over and backfires now and again, will check for spark in morning, electrics are my worst nightmare lol.

At a guess, I'd check the HT leads.

The weather is all over the place at the moment with large shifts in temp and humidity, so there's a decent chance that condensation could be the problem.

Problem found, took generator cover off and found that the pulser coil had come loose, one screw was loose and the other out altogether, on closer inspection it looks like either the coil or screw has damaged the generator wires were they go into the back of the generator, the pulser coil has also got a chunk out of it, so new generator and pulser coil on order and back on the road, thanks.