R1100RT Big Bearing R&R Question

m_stock10506 · Oct 29, 2019

Asking for comment from folks that have actually done this repair themselves.

This is my second big bearing replacement.. Bike is 2001 R1100RT. This one lasted 110k miles and I caught it very early. Once I saw particles on the magnet I really couldn’t bring myself to keep riding even though there was still no perceived movement at the wheel. The FD is off the bike and disassembled and there’s a little bit of play in the big bearing.

Question is this. The videos of the bearing install show the bearing dropped on the crown wheel and falling into place with a click. My first R&R the bearing didn’t bottom out with that click and I wasn’t confident that it was in position, so I bought another bearing and had the local shop install it. I did that one with the bearing heated up and the crown wheel from the freezer. What steps do I need to take to make sure that the bearing gets into the correct position on the crown wheel? If it doesn’t go on all the way, can I use a drift on the inner race to complete the install? Obviously I would rather that it just fall into place without any doubt. Thanks.

dieselyoda · Oct 29, 2019

If you have a heat gun, not torches, heat the bearing to about 190F.

Before doing that, put the crown in a freezer for a day or so. Other options is to use a CO2 fire extinguisher or a can of CRC Freeze Spray. Dry ice is my favorite, and the leftover dry ice always freaks my neighbour's kid out when I drop into a cup of water.

Make yourself a little wooden box so the crown fits in snug, lay it on the floor, not the bench.

Bearing hot, crown frosty, a little 3 in One Oil, drop bearing on straight if such a thing could be ever possible and then if needed, finish with a brass drift with an oval face and tap away until she rings.

It's a backyard, bush fix but if you don't have a press and the plates, works pretty good.

gsaddict · Oct 29, 2019

Crown assy in the freezer for 1 hour
Oiled Bearing heated to 200-225 f in a toaster oven.
Oven gloves to handle
Bearing hovered squarely over the lead in on the crown sitting on a tin can
Bearing will drop right on and will bottom
Hold down for 5 seconds
Done
Confirm bearing is bottomed.
Check for correct shimming.
I prefer the solder method.

m_stock10506 · Oct 30, 2019

DONE!!

Thank you to the two very knowledgeable responders. Left the crown wheel in the freezer overnight, put the bearing in the toaster oven for 15 minutes. Crown wheel was way below zero and the bearing was about 215 F. It bottomed on the crown wheel with a satisfying clink.

robsryder · Oct 30, 2019

Were the old and new bearings of the same thickness?

gsaddict · Oct 30, 2019

robsryder said:
Were the old and new bearings of the same thickness?

The clearance (C3) comes into play as well.
Shimming must be checked each bearing change for longest service life

Omega Man · Oct 30, 2019

Great information guys

Added to the Tag Cloud.
OM

m_stock10506 · Oct 30, 2019

robsryder said:
Were the old and new bearings of the same thickness?

Yes. Both bearings measured 17.953 mm.

robsryder · Oct 30, 2019

GSAddict said:
The clearance (C3) comes into play as well.
Shimming must be checked each bearing change for longest service life

If nothing changes but the bearing and the old and new bearings are the same, then the shims and resultant clearance would be the same. Since this is the third bearing installed on the OP's bike and the first replacement was done by a shop (local BMW dealer?) one would hope that the shop checked the original and first replacement bearings for thickness. This presumes that the shim/clearance was correctly set at the factory.

If the oilhead final drive is similar to the airhead final drive, I recall a BMW mechanic once telling me that the shop labor for reshimming an airhead final drive was 5 labor hours. The second degree of freedom (i.e., two axes of rotation) complicates the proper setting of the shims. This was mostly in reference to the replacement of the pinion and ring gear set rather than just replacing a bearing. It seems that one used a blue dye on the ring and pinion gears to check that the teeth were meshing properly. Thus, there were several assembly / disassembly iterations needed to converge on the proper shim / clearance. I have an example airhead final drive that I purchased used from Gator a long while back that illustrates the hazards of improperly shimming the final drive (or of using mismatched ring and pinion gears).

gsaddict · Oct 30, 2019

robsryder said:
If nothing changes but the bearing and the old and new bearings are the same, then the shims and resultant clearance would be the same. Since this is the third bearing installed on the OP's bike and the first replacement was done by a shop (local BMW dealer?) one would hope that the shop checked the original and first replacement bearings for thickness. This presumes that the shim/clearance was correctly set at the factory.

If the oilhead final drive is similar to the airhead final drive, I recall a BMW mechanic once telling me that the shop labor for reshimming an airhead final drive was 5 labor hours. The second degree of freedom (i.e., two axes of rotation) complicates the proper setting of the shims. This was mostly in reference to the replacement of the pinion and ring gear set rather than just replacing a bearing. It seems that one used a blue dye on the ring and pinion gears to check that the teeth were meshing properly. Thus, there were several assembly / disassembly iterations needed to converge on the proper shim / clearance. I have an example airhead final drive that I purchased used from Gator a long while back that illustrates the hazards of improperly shimming the final drive (or of using mismatched ring and pinion gears).

I have seen more than 1 final drive that was NOT checked when done at the dealer.
It is rare that I don't reshim any one I do. They typically came out too tight to begin with. I think Anton would report the same.

Every one I do is checked and and dealt with accordingly.
Oilhead Big bearing shim check (preload) is a 1/2 hr tops.
Your call if you want to assume yours is correct.

R1100RT Big Bearing R&R Question

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