I just answer this same question on the one below this (check out the response). You need to to make sure the plug is sparking. Remove it from the engine and connect it to the HT lead. Hold the spark plg so that the spark (Gap) end is touching the metal frame of your bike and turn the ignition over. You should see a healthy spark. If there in no spark the the problem is an electrical one in the ignition system. The good news is that it will be easy to find and not masively espensive to fix.
If the plug is sparking fine then the next thing to check is the fuel flow from tank to carb to engine. Read my reply to the next post for what to do there.
If you still have no joy in getting it going then post a reply and we'll take it from there.
Angela
February 2008