Just had my K2F completely re-built, stripped re-wound coil new bearings and condensor etc £180.00. Its the 5th one done by same bloke T.Salmon Burnham on Crouch ( actually his son has taken over ) broken cam housing replaced with good s/h one. Looks like new too. Never had any problems from any of them. Its the first job I automatically have done to a newly acquired machine, with unknown provenance I don't wait for it to start playing up. As has already been said, a failed Mag isn't a road-side repair.