Play in drive train?

[jacksdad63]

Hi there, I've a feeling that the free play in my bikes final drive is now a serious issue.

Its always been a little 'loose' but its now got worse: I put the bike in first gear then measured how much the rear wheel moves before the gearbox/drive train moves.

I marked the outer edge of the wheel rim, then rocked the wheel, its moves 2" or 50mm. that's the total amount the wheel moves before it locks against the gearbox, one direction to another. 

I'm wondering if the driveshaft to gearbox splines are shot, or is it adjustable with shims etc. like other shaft drive bikes?

I searched online but have only found the 'worn out gearbox output splines' horror story! 

Its a 1998 R1100RT and has done 68,000 miles.

[dirtrider]

13 minutes ago, jacksdad63 said:

Hi there, I've a feeling that the free play in my bikes final drive is now a serious issue.

Its always been a little 'loose' but its now got worse: I put the bike in first gear then measured how much the rear wheel moves before the gearbox/drive train moves.

I marked the outer edge of the wheel rim, then rocked the wheel, its moves 2" or 50mm. that's the total amount the wheel moves before it locks against the gearbox, one direction to another. 

I'm wondering if the driveshaft to gearbox splines are shot, or is it adjustable with shims etc. like other shaft drive bikes?

I searched online but have only found the 'worn out gearbox output splines' horror story! 

Its a 1998 R1100RT and has done 68,000 miles.

Afternoon  jacksdad63

 

That probably isn't too far off, try it in 5th gear also, in the lower gears BMW designs in a larger amount of slop in the transmission shafting dogs to gear slots, this is to make shifting easier. Most riders don't ride in the lower gears for long so the extra slop is not an issue. For the top 2 gears they tighten the tolerance a little tighter so the rider doesn't get that on/off throttle disconnect feeling.  

 

The BMW 1100 5 speed motorcycles don't have a lot of spline issues, every now & then you hear of one but not very often. 

 

If you are worried, you can remove the starter then zip tie the clutch lever in then use a sharp pointed wire or pick to rotate the clutch disk on the splines to get an idea on the spline wear. 

 

You could also have some wear in the drive shaft U joints, or drive shaft splines, plus the ring/pinion backlash, plus the transmission gear tooth backlash, plus the shifting dog lash, plus a little clutch disk spline wear, that all adds up when measured at the rear wheel. 

[jacksdad63]

Hi again DR,

thanks for the help, its just the same travel/play in each gear. Having heard many tales of terminal spline failure, I was thinking of either stripping and re-conditioning the gearbox (hard work) or replacing the entire box (easy but expensive and hard to find).

I've bought a 19k mile  ex-police bike engine, which I'm going to fit this winter, mine has done 68k and has a couple of minor oil leaks starting to show. 

Would a gearbox job be worthwile though? If its just normal wear n tear I'll live with it...they are called tractor gearboxes after all   

[dirtrider]

8 minutes ago, jacksdad63 said:

Hi again DR,

thanks for the help, its just the same travel/play in each gear. Having heard many tales of terminal spline failure, I was thinking of either stripping and re-conditioning the gearbox (hard work) or replacing the entire box (easy but expensive and hard to find).

I've bought a 19k mile  ex-police bike engine, which I'm going to fit this winter, mine has done 68k and has a couple of minor oil leaks starting to show. 

Would a gearbox job be worthwile though? If its just normal wear n tear I'll live with it...they are called tractor gearboxes after all   

Afternoon jacksdad63

 

Before making any decisions you should probably remove the starter then see how much clutch disk to input spline wear you actually have (disk rotational play on the splines). This should be your guide on what to do.