OK so....you put your R1200GS on the centre stand and select first gear. You then grab the rear wheel and rotate it fowards and backwards. How much free play is there? I'm beginning to thing mine has too much slop in it.
Drivetrain backlash....
- Thread starter Schtum
- Start date
Mr K
Registered user
Don't
Mike, does that not also include any free play through the gearbox? I can't think now if there woul dbe any, but to do a proper test you really need to exclude that as I'm sure you would get some. Trouble is, I think the only way is to somehow lock the driveshaft which is difficult without pulling it from the back of the box. Or you might just be able to get a hand in or something between the gaiters?
Good point Clive. I think, in fact that the freeplay is in the gearbox. I can feel the driveshaft turning when I move the rear wheel.Muppet said:
Ken H.
Guest
TADT
At the outer circumference of the tire, 3 - 5 cm of movement is not unusual. BMW trannys have had this lash for decades.
At the outer circumference of the tire, 3 - 5 cm of movement is not unusual. BMW trannys have had this lash for decades.
see 11** as well - its a bwm thing
http://www.ukgser.com/forums/showthread.php?t=71023&highlight=driveshaft+play
http://www.ukgser.com/forums/showthread.php?t=71023&highlight=driveshaft+play
Try and ride as smoothly as you can, learn to blip the throttle on downshifts, roll smoothly on and off the throttle etc. if you don't already do it. Thats about all you can do, the slack is just another part of the bikes "character".
The transmission slack is there by design from new due to the meshing clearances required in the gearing and rear drive. Virtually all gearing, and especially crownwheels and pinions, have a degree of backlash in them to allow for thermal expansion and to provide a sufficient 'oil wedge' between the mating faces of the gears when turning.
Obviously on a conventional chain driven bike you can make adjustments to the drivechain tension to minimise the feel of slackness when riding. On a shaft drive GS that slack is non-adjustable and always noticeable.
So long as your bike rides okay, makes no horrible noises or fails to select gears, and your rear wheel has no sideplay through a worn rear hub bearing (different problem - not backlash) you can relax.
The transmission slack is there by design from new due to the meshing clearances required in the gearing and rear drive. Virtually all gearing, and especially crownwheels and pinions, have a degree of backlash in them to allow for thermal expansion and to provide a sufficient 'oil wedge' between the mating faces of the gears when turning.
Obviously on a conventional chain driven bike you can make adjustments to the drivechain tension to minimise the feel of slackness when riding. On a shaft drive GS that slack is non-adjustable and always noticeable.
So long as your bike rides okay, makes no horrible noises or fails to select gears, and your rear wheel has no sideplay through a worn rear hub bearing (different problem - not backlash) you can relax.
Mouse
Registered user
If you peer in through the gearbox filler hole you can see where the backash originates.
Yes.....thanks for that Mr Puk. That's a good illustration of why we need context. Perhaps I should have added that I've been riding Boxers on and off for getting on for 30 years......Pukmeister said:
Given that the amount of backlash appears to have increased very recently and that the gearbox has just been off the back of the engine to repair a leaking oil seal, it is, believe it or not, actually a very sensible question.
Ken H. said:
I would have said more than that. And my Honda Pan Euro had exactly the same thing - its simply an accumulation of all the tolerances from the bevel box right back through the gearbox to the crank.
Still worried? Try the same thing on your car!
Given that the amount of backlash appears to have increased very recently
ok - what were the before and after measurements then ?
ok - what were the before and after measurements then ?
Shep
Shep of the Dessert
5 cm on the tyre centre line 1200 GSA Michelin Anakees part worn, in 1st gear
1200 GSA Michelin Anakees part worn, in 1st gear 
Schtum said:
Mine has loads of play, so does a mates, if it gets to more that 360 degrees then I will start to worry!
)
Shep
Shep of the Dessert
Schtum said:
Go on then, I got off my arse and measured the backlash on mine, as you asked, is yours better or worse
or is it after 30years of riding boxers your back just isn't upto bending down that far 
Shep
He's scotty-ish - he's too tight to turn the light on in the garage ( i think he's just been done for speeding by the looks of it )
50 mm ( 5 cm ) on the ancient,out-dated 1100 too - just for reference
( i think he's just been done for speeding by the looks of it )50 mm ( 5 cm ) on the ancient,out-dated 1100 too
- just for referenceTry running the engine in first gear (on the centre stand - rear wheel off the ground) and listen to the rattling from the rear bevel-drive. Sounds like a bag of hammers 
Apparently this is normal and there is a circumferential backlash of at least an inch (at the rim) when the wheel is stationary.
Must admit - it worried me
Al
Apparently this is normal and there is a circumferential backlash of at least an inch (at the rim) when the wheel is stationary.
Must admit - it worried me
Al
What's the point of this. You may well do damage as it's outside the operating parameters.
Haven't a clue, mate. It was a seat of the pants thing. It feels as if the amount of shunt from power off to power on and vice versa, has increased of late and an investigation by the method I described in my first post revealed a bit more slop than I'd have anticipated. Hence the question. Thank you for your answers, gentlemen...motomartin said:Given that the amount of backlash appears to have increased very recently
ok - what were the before and after measurements then ?
wilbjr21 said:
Well, it was actually a message to everyone that all these bikes display some really strange mechanical attributes that although may seem surprising......................... are actually normal.
You are not going to do damage to the bike by firing it up on stand and clutching out in 1st gear for a short period,
have a nice day
Al
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