Metal in Final Drive Oil

jivebiker · Post by **jivebiker** » Wed Jun 20, 2007 12:31 am

Advice please...

At my last (dealer) service, 24K, I had to have a new crown wheel bearing installed, at not insignificant cost.

Now I have come to my 30K service and decided to give it a bash myself, its only oils and air filter after all. I decided to do the rear drive oil despite it only being 6K since its bearing job.

Having drained the final drive oil, I noticed some small slivers of metal stuck to the drain plug magnet (one circular in shape - like a bearing flake), and the oil was a little grey looking.

Is this likely to be the crown wheel bearing again (perhaps having being badly fitted) or is there something else now to get fixed?

Do you think I should go back to the dealer??

What are the risks if I let it lie and see how it goes with new oil ?

Whats the best way to check the bearing for wear?

Any help / advice much appreciated.

Cheers

bigblackfalco · Post by **bigblackfalco** » Wed Jun 20, 2007 7:37 am

Could be the input bearing. I'd like to think that they changed/checked them both as they were working on it.
Bailey.

Cobbster · Post by **Cobbster** » Wed Jun 20, 2007 3:51 pm

Hi,
Don't sweat it mate, when I did the first oil change on my gear box the magnetic plug looked like Billy Idols haircut. Assuming the worst I changed it again after a few thousand miles, it was clean as a whistle.

Check/change the oil again after a few miles, it will probably be ok.

Cheers, cobbster.

PS. use Mobil 1 fully synth, it does make a difference.
PPS. What symptoms did you have when the first bearing went?

jivebiker · Post by **jivebiker** » Wed Jun 20, 2007 5:25 pm

Just to clarify, it is the rear wheel drive oil, not the gearbox (looking at that tonight!). Im happy with the gearbox as it is so am going with Castrol Syntrax.

Last time the bearing was knak'd, I noticed no symptoms. It was picked up by SBW during the 24K service, knocking the overall bill (plus tyres) to a gnat's under a grand!

I had a read of some threads last night and as a result, today checked the free play in the rear wheel.... loads! drained of oil there was a distinct knock as I twisted the wheel (holding 3 and 9 O'Clock) and again at 12 and 6.
With the rear brake on, the knock was all but gone.
I have filled with oil, and the knock is gone, but the movement is still there.

Having changed engine oil and filter, and now using 20w50 (Silkolene, semi synth) the engine seems much quieter than on the 10w40 it has had all its life.

As I had the bike on its centre stand I started it up and whipped through the gears to see what I could hear... what a racket! It sounds like metal to metal knocking in the swingarm... do they all sound like that on a stand? is it just unloaded lash? I certainly cant feel this when riding, but without earplugs today it is very noisy when I pass close to cars. A friends CX500 doesnt sound anything like that noisy on the stand, but doesnt have UJs like the S.

boxerpan · Post by **boxerpan** » Wed Jun 20, 2007 6:19 pm

jivebiker wrote: As I had the bike on its centre stand I started it up and whipped through the gears to see what I could hear... what a racket! It sounds like metal to metal knocking in the swingarm... do they all sound like that on a stand?

Don't do it....... the UJ's and shaft are all out of alignment on the centre stand

jivebiker · Post by **jivebiker** » Wed Jun 20, 2007 10:22 pm

Don't do it....... the UJ's and shaft are all out of alignment on the centre stand.

Surely no more so than when Im hard on the brakes at 70mph and the rear suspension tops out... which is a regular occurrence, or when the bike gets airborne over those lovely humpy bridges.

boxerpan · Post by **boxerpan** » Thu Jun 21, 2007 7:21 pm

jivebiker wrote:
Don't do it....... the UJ's and shaft are all out of alignment on the centre stand.
Surely no more so than when Im hard on the brakes at 70mph and the rear suspension tops out... which is a regular occurrence, or when the bike gets airborne over those lovely humpy bridges.

Are you running up thru the gears while you're topping your suspension out ?

jivebiker · Post by **jivebiker** » Thu Jun 21, 2007 10:49 pm

No, I'm usually about to start rapid downshifts.

The noise is from the shaft drive, not the gearbox, which should be able to perform its job at both extremes of suspension travel.

When I went up through the box on the centre stand, I did so carefully with gentle clutch action to avoid any snatching so I didnt topple the bike off the stand (even though I had a bag of cement resting on the front wheel).

Just the engine spinning the wheel caused a right racket... it could have been because it was unloaded and the free play was able to clank about.
Either way it surprised me it was so noisy.

If I spin the back wheel by hand (in neutral) I can't hear anything untoward.

Problem is I always ride with earplugs in, so whenever I hear the bike without it sounds like something from the 1930s.... now there's a thought...

20w50 has quietened the engine down a load though.