XChallenge Drive Sprocket Fitting

[ian640]

Hi,

Would be most grateful if someone could let me know:

a) The tightening torque for the screw for the drive sprocket on the XC.

b) If you need to apply loctite to the screw?

Thanks in advance,

Ian.

 

[Bendy toy]

Hi,

Would be most grateful if someone could let me know:

a) The tightening torque for the screw for the drive sprocket on the XC.

b) If you need to apply loctite to the screw?

Thanks in advance,

Ian.

Loctite might not be enough. But if it turns out to be too good getting heat into it could risk taking out the gearbox oil seal. Use the proper locking system (tab washer, spline washer or whatever).

I cant give the BMW torque but no need to go mad - its not taking any direct load. However it will be taking a lot of vibration so needs the proper locking system to stop the nut coming off.

 

[JohnnyBoxer]

There is no locking tab, just nut onto sprocket face
I think loctite is used effectively

 

[Losttheplot]

There is no locking tab, just nut onto sprocket face
I think loctite is used effectively

+1

 

[Micky]

+1

Not quite right though ....

Tightening torque 40Nm or 30ftlbs make sure the cup washer is on the right way round. It's very slightly dished, the outside edge of the washer needs be in contact with the sprocket

After market sprockets don't fit the gearbox splines too good and could fcuk them

 

[Timpo]

There is no locking tab, just Bolt onto sprocket face.

Parts 25,26,27 in the diagram below.

Loctite Threadlocker 243 is ample.

Tightening torque 40Nm or 30ftlbs make sure the cup washer is on the right way round. It's very slightly dished, the outside edge of the washer needs be in contact with the sprocket.

After market sprockets don't fit the gearbox splines too good and could fcuk them...

The problem being though Micky is that the trail rider needs a lower ratio, and if i remember correctly, the 14 tooth has been discontinued by BMW, so there is no option but to use a pattern sprocket, ie, AFAM, Talon or Renthal.
I wonder what the Husky Terra ratios are, and whether Husky are listing a smaller sprocket as OEM option?

 

[ian640]

Thanks for all the replies, to the freezing garage now, torque wrench and loctite in hand. I'm using the standard BMW sprocket, 15T I think.

 

[JohnnyBoxer]

Not quite right though ....

Tightening torque 40Nm or 30ftlbs make sure the cup washer is on the right way round. It's very slightly dished, the outside edge of the washer needs be in contact with the sprocket

After market sprockets don't fit the gearbox splines too good and could fcuk them

Just checked mine, it's fitted in it's dished shape - with the middle making contact and not the outside edge

Not my doing (will it make a huge difference)

Been using 14T Talon on the front and splines seem fine and it's a very snug fit onto the shaft

 

[Micky]

Just checked mine, it's fitted in it's dished shape - with the middle making contact and not the outside edge

Not my doing (will it make a huge difference)

Been using 14T Talon on the front and splines seem fine and it's a very snug fit onto the shaft

Shouldn't think so JB .... I went for the full life of a chain and sprockets on the 800 with it the wrong way

 

[JohnnyBoxer]

Shouldn't think so JB .... I went for the full life of a chain and sprockets on the 800 with it the wrong way

On the parts diagram, you can just about make out the correct way of fitting.


I can see the reasoning, but at 35nm all it's doing is holding the sprocket snug on the shaft and that's a fair torque

 

[ian640]

Going slightly off topic I'm keen to fit the sprocket correctly. Almost 10 years ago to the day my drive sprocket came off about 100km south of Tamanrasset, more or less halfway across the Sahara. Fortunately the sprocket and screw were caught by the giant rally basplate I had fitted to the bike and I wasn't travelling alone, but it was still a slightly scary experience. Spent Xmas day 2002 in In Guezzam mainly waiting for the next tanker to arrive to re-stock the local fuel station and not a cool beer anywhere to be seen.