Hi All ,
Spose I should have introduced my self , ex Greeves Comp Dept , Guzzi , Ducati , Suzuki , MZ , CCM , Yamaha & and anything else that came into the dealers .
Currently have two Goldstars , an A7 and a pre war single .
The idea of metalastics is to give torsion to the swinging arm etc that they are fitted to , yes, sitting on the bike then tightening the spindle will give the same effect and is probably not far from half movement . Preloading the bushes applies to any make of bike that has them .
Don't forget that the swinging arm pivot being the pivot point has very little movement compared to the wheel/damper end .
The spindle should be a sliding fit in the frame mounts , too much slop can make the wheel/swinging lay at an angle relative to the frame .
The same applies to the solid spindle arm & the hollow spindle later frames .
It is not uncommon to see large washers brazed on the outside of the frame mounts to repair worn holes but drilling oversize and fitting spacers looks much neater .
Far as I recall the tube that the bushes fit into is parallel right through .
I think most of the Goldstar parts suppliers sell spacers to convert the hollow spindle frames to solid type , these could be used to repair damaged arm mounts .
The only danger when drilling out the frame mounts to repair them is not getting them in line bit like repairing the center stand lugs when they wear out through lack of grease or the nuts being loose .
Chris