And when buying a new plug get a spare. Don't know how many times I've hadmates saying come over my bike won't run, it's getting fuel and it's got spark, etc etc. Slap in a new plug and bang, it's running. JUST BECAUSE IT MAKES SPARK WHEN YOU TEST IT DOESN'T MEAN IT WILL UNDER COMPRESSION.
And buy a can of autostart too, that way it it won't start and you put in the new plug and still no fire, try the aerostart and if it starts, you got a carb problem (probably blocked jet/s).
And don't use fuels that have ethanol in them, the ethanol not only eats up rubber o rings and seals but being alcohol it absorbs water which will make you bike run like crap and start corrosion in your carb. Not only should you be draining you fuel bowl, but your tank too unless your riding it in the next week, petrol doesn't last long in a plastic container and hell it only holds $5 of fuel. If you can't afford that get a pushy.
Alright rant over, I just spent a couple hours tonight driving to and from a mate's to fix his 50 that I had running in 5 mins after he'd f#@$ ed with it all week, we have a deal, if I can get his bike going in less than 10 mins he owes me a slab. He currently owes me 3 this year