Hey phil, welcome mate, great place is foc-u....really active although we're going into the quiet winter season..
You may be knowledgable already if youve had the bike 2 years............but have you ever checked your front sprocket nut????....known fault...basically the nut strips the thread on the shaft & falls off, yours could be fine....or it could be hanging by a thread.....cheap fix...uprated, wider nut from yamaha about £10
Use the searchfunction along top of the site, type sprocket nut & search...all the info youll need.
& yep get some pics up of the
