I don’t think you could describe a GS500’s chassis (left) as something that Brunel would have tipped his hat to. Thin bits of box section glued together with spit and braced with stamped bits of plate. You get what you pay for and GS500s are not to be mistaken with the GSX-R pocket rockets.
Anything too clever or hefty would merely see the GS’s subframe wilt like the late summer corn. Up to a point a beam could be added from the pillion mounts down towards the footrests to help support the back end (right).
Trying to work out how to make the platform (or get it made), it occurred to me that a metal support tube as strong as any on the machine was staring me in the face: the silencer. By chance I’d had the pipe lowered to make room for my planned DIY panniers (which eventually became a set of Magadans) until a light bulb flickered momentarily: use the pipe.
All that had to be done was separate the pipe’s heat (not that much on the pre-catalyzed GS5) from the bag’s base and possibly add support at the back. A mention of Giant Loop’s good-but-too-short stainless pipe guard (above right; £15) gave me the idea to make my own from a bit of 2 by 4 ally off-cut.
On top of that screwed a layer of plywood on which rests the pannier. The good thing is that my Mags are throwovers so the full weight need not be taken on the platforms. But there’ll come a time when that needs to be done so I added a support from the silencer’s snout to the subframe using a 2 1/2 inch exhaust clamp (left).