This needs a bit of care when dismantling as the springs are under considerable compression so if you get it wrong you could lose some teeth .
If you decide to use stainless steel spring covers note that ones made for a BSA are slightly smaller in diameter than Sunbeam ones and will not fit , as I found out the expensive way .
However if you fit the BSA , A or M group main springs they give a considerably more comfortable solo ride , these springs may be identified as below
6.625" LONG , 2.00" OVERALL DIA , 13 TURNS , 0.275" WIRE .
For a safe and effective of replacing the springs you need the following , 15 inches of suitable threaded rod with two nuts locked onto one end , two plain washers , two steel discs 1 ½ inches diameter by about 3/16 inch thick with the centre hole slotted out to one side , plus one more nut .
Hold the rod upright in a vice by the two nuts then assemble in order a plain washer then a slotted disc , followed by the complete spring assembly , this is then topped off by disc , washer and nut in that order.
The spring assembly may now be safely compressed until it can be slipped into the frame and then unwound until the nuts are loose , the slotted discs can now be carefully knocked out , bottom one first and the rod removed . Then after lining everything up the centre column can be replaced , be careful that the weight of the drive unit does not cause it to slip out of the frame and finally to line up the grooves for the bottom pinch bolts .
