I would seek a resolution - it will likely become an MOT failure - there is not meant to be slop on such parts of the suspension
the whole idea of what flex and movement we want from a swinging arm, is a real black science very few chassis engineers understand - in the motoGP world once upon a time Honda managed things (possibly through luck) quite well, then lost the plot - and now they all fall off and have won nothing for ages...
when leant over a bike's suspension doesn't really do much, and its chassis / suspension flex that makes some bike's handle well and cope with lots of conditions way better then others (think Norton featherbed and such).
as power went silly, massive rigidity in some areas of the swinging arm became vital to stop the bike doing weird stuff - whilst mega flex and compliance in others planes makes it handle.... When Honda first used the back of the engine to hang the swinging arm pivot on (check early fireblades), they got lucky with a skinny weird design that just worked - a stark contrast to many other manufactures, but it worked and they applied to lots of stuff and they had great bikes - but now have no idea what they are doing, so it must be they never understood it ???
It was a similar thing with Stoner and Ducati (and again why Rossi couldn't ride one), the V of the engine meant they naturally rolled on to the idea of almost zero frame – just mount everything on the engine to save weight and complexity - but this meant there was no chassis flex - engineers had no idea. And year on year they made stronger stiffer forks added more and more rigidity and the lap times dropped and the riders just threw them down the road like clockwork - in many ways this lack of understanding is the sole reason they developed save the day electronics – which in turn has led to the hideous tyre construction the gamer halfwits now use with glee - and so we now get vague whishy washy steering and strange sensations old school riders can cope with... But on Public roads we aren’t all Spanish brain dead lemmings operating an on off switch just because that’s what the 50 year old regs mandate.
Stoner won the championship, even though the bike was basically unrideable - mainly because at the time Ferrari and Ducati were working together on crazy F1 engine tech and had produced an utter missile, bolted into a death machine - with all that power, using his talent (he was still on the bike going into and out of the corners, when no other Ducati rider was) it allowed his sheer bravery to get it to the front down the straights and Win...
He walked when Ducati wouldn’t listen and they just wanted to throw tech at the problem – Stoner knew it would destroy what racing was meant to be and allow brave fools to get to the front and Hello Mr Marquez !!!
After more seasons of disastrous result and even with Rossi unable to stay on the bike – they had to scrap everything and try a new chassis design and the rest is history – you can now only win on a Ducati - mostly thanks to the changes Stoner and Rossie were screaming for over many years - added to mega electronics the enginneers wanted to save face and super glue understeering tyres for gamers
Back to the BMW R1300 fun - So the slop somehow doesn’t argue with other ideas BMW seem to know about chassis tech. But it doesn’t mean it meets the rules on what mechanical integrity is required for use on British Roads. AKA Homologation should have picked it up (but of course thats operated by not done by idiots), and then the MOT test should certainly present problems...
The fact some do, some don’t, would suggest a level of hands on building in the factory that should be frowned on. I would hazard a guess either the engine’s come with rough and ready machining on the width of the engine mounts or is the frame squidged tighter to meet other parts that are too small and depending upon which Muppet over did the tightening torque on which bolts at what time – it means we get variable slop bike's out there…
It could be as much as a batch of frames or engines were machined too much and it wasn’t picked up due to apathetic quality control – remember the people building these are idiot rent a crowd assemblers (sure on massive pay and benefits), but they are not skilled engineers thinking about what’s going on. And when discovered the BMW accountants have looked at the costs and said fxxk it who cares
