F850GS clattering over slow-speed bumps from below seat LHS - source? Fix?

Porcupine

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My 2023 F850GS has an annoying clattery rattle when going over uneven roads/trails at ~10mph that I'd love to identify and fix.
It sounds like something plastic rattling up near the seat on the left hand side, or something rattling against plastic, like a 10mm socket left under the battery. It's not a buzz or a high-frequency vibration. "Clatter" is the best word I can think of to describe it. It's not continuous or predictable.
I've taken stuff apart looking for loose items or components but can't find anything obvious. It's not the sidestand, gear lever or rear brake lever, and I'm pretty sure it's not the centre stand.
I don't think it's the chain slapping against the swingarm - it sounds too lightweight and too high up - but I know some people have identified this as a characteristic of these bikes.
Anybody got any ideas please?
 
can you put the bike with rear wheel of ground and let it tick over in first while investigating.

Obviously keeping fingers away from hot or sharp parts that remove fingers lol
 
Yeah, that's a good suggestion. I'll try that this evening and see what happens. Thanks.
 
siwhite said:
Mine does that, and I always assumed it was the chain slapping the underside of the swingarm...
Click to expand...
I've read people saying the same, but this sounds like a more lightweight, plasticky noise than I'd have expected a heavy chain to make - and it feels like it's coming from near the seat.
 
Barnoe said:
can you put the bike with rear wheel of ground and let it tick over in first while investigating.

Obviously keeping fingers away from hot or sharp parts that remove fingers lol
Click to expand...
Having the bike on tick over is going too induce clattering from the slack chain....?
 
I didn't get chance to try running the bike on the centre stand last night so I'll try today.
 
siwhite said:
Mine does that, and I always assumed it was the chain slapping the underside of the swingarm...
Click to expand...
Both my f650 and F700gs did this , two up and at low speed. In my case it comes from the rhs and it is the chain. Pre 750 /. 850 /900 models ran the chain down the rhs.

If I re tension the chain correctly it goes away. I think its the chain leaving the the engine sprocket and catching the plastic sprocket cover or as others have said slapping the swing arm.

Certainly worth checking you chain tension as it a potential quick win.
 
Mate had clatter when Chain too loose and catches side of exhaust resonator box especially on bumpy roads on his 850 GS
 
Thanks gsman1. My chain is within tension but I'm sure that's where the noise is coming from. I've learned to live with it!
 
Having come to terms with the idea that it's not a fault, I don't really notice this any longer. I guess I was particularly keen to understand the source because the bike was new to me at the time.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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