My girlfriend has a 2007 S50 8oo. Great bike for her. Recently the one cyl. seems not to fire properly. I changed the plug, but no better. It idles fine, revs up fine in neutral. when riding slow it is ok. Under load that cyl. just mis-fires. Is there seperate coils for eack cyl? Could this be the problem or somethig else. Any help will be appreciated. Thanks.