Hi Tony,
'tis coming back to me, i'm pretty sure the factory mounts and the motogadget adaptors are both threaded M6.
I drilled the front mounts to do something different, didn't like that and ended up fitting the Triumph adapters. So that just has a cap screw through from the hidden side of the mount tightening into the blind threaded hole in the adapter. If i went back to the factory indicators i would need a nut on the hidden end.
The back mount isn't modified so could be returned to stock, and the front could be done this way as well. There is a cap screw which threads through the original mount from the inside, the adaptor was wound onto that, with some jiggling of the bolt and adapator you can get the adaptor to act as a lock nut (jam nut). So the cap isnt necessarily tight against the inside of the mount, it gets wound back a bit so that the adaptor is in the correct alignment when it locks both up.
Once all that is done feed the wires through etc. Best to use small connectors so that all could come apart if needed, or leave spare wire length in case the connectors need to be sacrificed.
