Final drive again

[centurion]

Hi all.
As per the previous threads, I drained the final drive oil to find metal flakes.I know there is always some gunge and stuff in there but this looked excessive. I have read all the other threads and having opened the bevel box there doesnt seem to be any major issues, I havnt had a good look at the large bearing yet but it feels OK which doesnt appear to mean much until you have had a good look at it.
The odd thing / fault that is readily apparent is that the small roller bearing can be lifted off the crown wheel shaft by hand no heating or pulling necessary .It looks as if it may have been rotating on the shaft (but not a lot, apologies to Paul Daniels). The question is , is the crown wheel shaft u/s Should I buy another bearing and use bearing lock to install it or should I just look for another bevel box.
Any advice gratefully received.
Thanks Centurion

 

[kennyc]

as far as I know the roller bearing is a tight fit to the crown gear shaft? maybe worth measuring the shaft and posting it to see if anyone has the correct dimension, the big ball bearing you need to check for broken cage metal or missing rivets, and if you have got it as far apart as it sounds then probably worth replacing it anyway, but first find out if the roller bearing being loose is a concern.

 

[Ian J Hartley]

Which one are we talking about.

Bearing 3 in a ball bearing. No play at all

Bearing 5 is a tapered roller bearing so it will have lots of play. Check the bearing casing for wear, the surface might be shinny, that's normal, but no groove or roughness, does it feel smooth to spin, or rough.

Ian

 

[Canuck]

In some cases initial inspection of the 'big' bearing the case may show no damage... but unfortunately it can all go wrong very quickly! If you have too much fuzz on the plug I'd advise just changing it when and where you want.

 

[Dusty]

Hi Centurion

just to pass on my recent experience... i was back home for the North west 200 a few weeks ago... i did a bit of touring around donegal and alike... i did almost 1600 miles over 6 days or so from checking the final drive oil..... i parked the bike up and 1 hour later the entire contents of the final drive was on the floor.

i checked for movement of the big bearing amd there was no movement at all. Clearly the oil was coming from the hub and wheel marriage...

when me and the mechanic looked into the drive the cage was completely gone and had penetrated the seal..... there was one shim in place....my understanding is that the shims are design to keep the fit and movement to a minimum... mine had one and apparently others have more. I dont know whether mine needs more shims to make up the difference , but one came out so one went in......

Some one who knows more about the shimming will no doubt comment but is this an issue worth considering and investigating further????

im sure there is a you tube video about the shims, ill see if i can fing it

dont know if this helps

dusty

 

[centurion]

Thanks for the comments,
The bearing I am enquiring about is 5 in the diagram the small roller bearing. It appears ok no missing bits pitting or anything else of note . Except all the threads I have read suggest it should be a such a tight fit in the crown wheel.That it should be heated and pulled off. Mine whilst not very loose can be lifted off with finger pressure. Should I replace it of use bearing fit.
The big bearing seems fine but as I am in there I,m going to replace it anyway as Im off to France at the end of the month.
Thanks Centurion

 

[Ian J Hartley]

Thanks for the comments,
The bearing I am enquiring about is 5 in the diagram the small roller bearing. It appears ok no missing bits pitting or anything else of note . Except all the threads I have read suggest it should be a such a tight fit in the crown wheel.That it should be heated and pulled off. Mine whilst not very loose can be lifted off with finger pressure. Should I replace it of use bearing fit.
The big bearing seems fine but as I am in there I,m going to replace it anyway as Im off to France at the end of the month.
Thanks Centurion

My bearing No 5 when I checked it could move up and down by about 5 mm. It moved freely and span smoothly. There was no excessive wear on the friction surfaces to warrant changing it so I left it in place. You'll find the replacement new one will have slop in it. It is after all a tapered roller bearing and the they only fit properly when under a lateral load.

Bearing No3 is the one all the main talk on the forum is about. It has to be fitted and removed with heat, and is the usual one to fail.

But at the end of the day it's your bike, and your decision.

 

[uncle dick]

If you have swarf in the oil I'm more inclined to think pinion bearings than the big 'No.3' bearing. Does the input shaft rotate smoothly?

 

[Packer]

The centre of bearing part #5 must be a tight fit on the shaft. In engineering terms I would expect it to be described as an "interference fit", i.e. no chance of it moving unless it's with heat and or a bearing puller.

I was able to do most things on my 1150GS including stripping it for a cosmetic refurbishment. I had previously changed out the original big bearing and seal when it failed at 26,000 miles and my efforts were good for 35,000 miles but the replacement at 61,000 miles lasted less than 10,000 which suggested that something more was wrong. At that stage I sent the entire final drive to Scriminger Engineering for a complete rebuild with any parts required. It's worth it for the peace of mind if you are doing a long trip, particularly overseas. I seem to recall that it was around 69,000 miles at that stage and when I sold the bike at 96,000 miles the final drive was still great.

The input shaft needs special tools and a jig to anchor the assembly to a heavy bench as the torques settings are big numbers, 135Nm if my memory is right.

 

[centurion]

Thanks for the update, Thats what I thought the small roller bearing should be an interference fit on the shaft.
rgds Centurion