I'll excuse the pun
Starter failed a few weeks back, went to the Dalesman Rally in July with Hovis, no probs, bike sat in the garage for less than two week's, had the Optimate on, go to set off for the Pilgrim Rally and the solenoid is just clicking away, connect my 85 a/h leisure battery, still nothing, rocked it in gear engine turning ok, took the starter cover off (if you have never done this you have to deform it to get it out of the bloody frame) fed 12v direct to the starter terminal with a seperate earth connected (starter should spin freely, because not engaged) nothing, dead, remove starter seems to turn ok but oil present, crankshaft oil seal weeping, decide to leave the GS and it's off to Chelmsford on the twist n go loaded with full camping gear (thanks to Bomber previous owner of my Burgman, ran a treat Dave, 500 mile round trip to a bike rally and i got my first ever award from the Mayflower mcc for 'Tale of Woe' and i was not the only one there on an alternative bike because their B@W had failed.
Anyway, a friend has had the starter to bit's and could find nothing wrong apart from oil, he has cleaned and greased it, bench tested it i brought it home, checked the ring gear for damaged or bent teeth, none found, fitted the starter all terminal's clean and tight, solenoid clicking only

Feed 12v to starter terminal and it spins freely, i am sure the gear is not meshing fully with the ring gear hence the terminal's in the solenoid not mating and giving power to the starter!
What am i missing?
Yes yes i know i should have kept my other reliable GS's
