Last year I fitted frame plugs into the lug holes on the subframe. Tidied everything up I thought.
Anyway, a few weeks back, I lost one of the plugs. Returned from a days hooning, and one was missing. Gone.
Pain in the arse, but no biggie. Ordered a replacement which arrived today.
Tried to fit it, there wasn't sufficient clearance for it to fit in snugly as before.
Closer examination revealed that the M8 subframe bolt had backed itself out, and 'ejected' the plug.
I have NO idea what could have caused this to happen, so I've just nipped it back up again, with some Loctite 243 for good measure.
Bike has slightly less than 3000 miles. Quick heads up, recommend you check the 4 subframe bolts when you have 5 mins.
Prevention is better than cure etc...lol...FWIW the offending bolt was the top L/h one.