1977 850 mk3 Interstate Left Hand Side Panel Original or Pattern or Wrong Type

My bike is pretty much original apart from the paintwork, but I feel that the left hand side panel in fibreglass held in with a plastic dzus fastener is an aftermarket part or perhaps came from an earlier model with the right hand side panel in all steel. I would like to know any of your thoughts on what it should be?

The shape is correct, but I believe that all the later parts were steel.

My 76 Interstate uses fiberglass side panels. Registered 76 , but recently I found it to built earlier . See Avatar.

The plastic Dzus style fastener is original. The MK IIIs originally came with steel side covers. However, the steel 850 side covers have not been available for years. Andover Norton does offer fiberglass, aka GRP. I would suspect that the previous owner lost the original steel side cover. The Dzus fasteners would fail, causing the cover to fall off while riding. It was probably replaced with a fiberglass replacement.

I have steel right side, grp left. Both are attached at their top face, with bolts to the frame. So they're not reliant on the dzus to keep them on the bike. Is that not usually the case?

Mart UK said:

I have steel right side, grp left. Both are attached at their top face, with bolts to the frame. So they're not reliant on the dzus to keep them on the bike. Is that not usually the case?

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It's always the left side / battery side that falls off and goes skittering down the road.

My R/H is the original steel panel held on by two 7/16” AF set screws and the L/H panel is glass fibre as in the photos which I can’t say is an original fitment or not? The L/H panel is held at the top with a single plastic dzus fastener, and unless it shears I can’t see the panel falling of to easy (tempting fate).

Lovel said:

My R/H is the original steel panel held on by two 7/16” AF set screws and the L/H panel is glass fibre as in the photos which I can’t say is an original fitment or not? The L/H panel is held at the top with a single plastic dzus fastener, and unless it shears I can’t see the panel falling of to easy (tempting fate).

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Change that , it will fall off ( sooner or later ) , like mine did . Luckily as it came off , my wife who was on the back actually felt it come undone and pressed her left leg in to hold it and then knocked at my shoulder 3X , that's our pre-arranged signal to pull over NOW . Usually it's to pee desperately in the bushes or wherever. Pee-ed there and strapped it in with the camping gear on back. On return from the trip I fixed a nut and teflon slot screw bolt arrangement to hold it . She's a keeper , like the panel.