Hello All 
I need some advice 

I brought a rear main seal from Motorbin  ( The BMW ) brand one   and it had the instruction on the site to soak in oil for two hours before installing.

long story short  - I stuffed up installing this seal and deformed it. so I ordered another one form Munich in Western Australia so i could get it before the weekend  

The   ( BMW ) brand one from Munich states install dry  but it has exactly the same  part numbers  
So  this is the first  difference  in install 
I have contacted both wholesalers and they stand by their instructions.  

I also have been reading different threads and 50 % state to stretch the seal first  over ( Pipe / Socket / Pill Bottle ) the others state don't  do this.
So  this is the second difference  in install 

Then further reading state that the  oil lip needs to be towards the front of the engine  and others state that it rolls back on-itself to face the back of the bike  
This seems strange to me and I might be reading it wrong or the the thread is incomplete  ?? 

Thank You in advance

matt the ones suggested to put over with a pill bottle are the thin Teflon types , and usually for the seal at the timing chain - hall sensor seal at the front of the engine   the profiled seal at the rear- clutch is a very different material ,
press the seal home dry
then lubricate liberally the seal lip and the clutch mount shaft whilst reassembling carefully .

good luck

- newer seals made with PTFE should be installed dry
- the seal membrane should curl back to face the front of the engine when the clutch is installed. Nothing you need to do to make this happen
- No need to stretch the seal (have never heard of this. References please)

- install the seal carefully. use a hammer and wooden block, hammering gently and measure often to ensure the seal is being driven evenly
- make sure the seal face sits 0.5mm proud of the casting face. Do not drive it fully home flush with the casting.

Thanks Guys

So the my RS developed a leak at via the breather hole in the bell housing  about 500 km after replacing the Rear Main Seal 

So on the week end I started the second attempted, interesting it only took about 2 hours to get the gear box out and onto the work bench 
compared with my first attempt

When lift the gear box onto the bench I can see a sheen of oil around the Gear Box  Input spline  

and when looking at the clutch side of bell housing it seem free of oil       

I know your meant to be able to smell the difference between the oils, but with my sense of smell I cant tell the difference.
it come in hand living with teenage boys and the wife cooking


Question
If the Rear main was leaking oil would it appear around the  Gear box Input shaft ? 
I can see how  but a stupid question  is one not asked 

In replacing  the gear box input shaft oil seal do you just pick it out and re-seat a new one in place  or is there additional work that should be done  ?

The rear main seal leak will usually show up as engine oil inside the housing but iy usually doesn't get on the clutch but if the big O-ring is leaking that will often get on the clutch and possibly the face of the transmission. If the front transmission seal is leaking it will get on the clutch and face of the transmission however transmission oil can get from the seal on the rear of the main input shaft leaking (behind the throw out bearing and runs down the pushrod).
Smell some transmission oil in the bottle and compare with engine oil. Unless your nose is missing then you will smell the difference.

Matt if you need a hand or a nose give me a yell. As per Rick if you have no sense of smell get one of the boys or the Boss to have a whiff.
Regards Martin

Well oiled up the bike 
And gave it a short test 
Seem like the piddel has been fixed 

Need a longer run now to find the next one

good to hear Matt

hmm feel like a run to  get the banner and meet twb on Saturday ?

not sure of details yet ....

Saturday is a bad day for me  

Boys sports and the like start earlier morning and don finish till 5pm

 Sunday is clear

yep remember that well matt

4 to pickup , one to hockey , 2 to rugby , then pickup the hockey then back to rugby
sunday  was rugby only ...but could be anywhere in the greater Brisbane area .usually home after lunch
later was 3 to rugby
...then drop off again ...home by 6pm

summer was far easier ...giggles

Hello all 

Still trying to sort out the leak from the bell housing weep hole 

So i took the gear box out again to day  
Im getting really fast at it now 

I removed the clutch pack and basket 
When i undid the center nut oil weep out past the cener o ring 
I was able to pick out the oring in one piece using a krone tool 
Last time i had to cut it 

Does this mean it was installed incorrectly ? 

After removing the clutch basket i put the oring back on the shaft and noticed that its very loose / sloppy 

Is this correct ? I cant see how it would work being so sloppy ?

Matt what days are you home, I can try and get over. Could you see where the oil was coming from.
Regards Martin.

Hello All 
I measured the old center oring which came out of my bike last night and seems sloppy on the shaft at 18.64mm 

The new one measure 19.14mm and seems even more sloppy 

Do these compress once you tighten the center nut ? 

Or should I go and get another one from an o ring shop with a smaller diameter ? 

Once again thanks for the input 
I want to stop this leak 

Also iI noticed that you can feel the joint between the bottom block and top block on one side is this normal ?

Matthew-Brisbane wrote:I measured the old center oring which came out of my bike last night and seems sloppy on the shaft at 18.64mm . . . The new one measure 19.14mm and seems even more sloppy . . .Do these compress once you tighten the center nut? . . . Also iI noticed that you can feel the joint between the bottom block and top block on one side is this normal ?

The stock O-ring has a 19mm inner diameter and a 4mm cross-section. What was the cross-section of your choices? They compress when tightened. The thrust washer beneath the nut also is called a compression ring in the parts fiches. Follow BMW's tightening guidelines.

It's normal to feel joint seams. There's just something attractive about them.

Both o rings have the 4mm cross section 

Just inner diameter and outer diamter changes on both the orings 
That I have 

Just seems really sloppy on the shaft

Matthew-Brisbane wrote:Just seems really sloppy on the shaft

It's difficult for us humans to understand what appeals to an O-ring.

Anyway, I'd opt for the genuine article with the correct dimensions—differences in aftermarket O-ring material might have an effect—and tighten the nut onto the compression ring according to BMW's guidelines. I'm just that unadventurous.

The old one came from motorbins 
And the new ones from motor works 
Will upload a photo tommrow showing the differences

The bottom O ring came from Motorworks and the top one from Motorbins  
As you can see there is a fair bit of difference in the internal diameter

The internal diameter should 18mm and thickness 4mm so the lower one is not right.

Thanks Rick  

Determined to stop this leak

Hello All  

So I ordered a new Oring from a good supplier of parts in Aus  and also brought one from a local dealership  

Now I have 4 different size Orings  and confused at which one the best to use  

Does anyone know the exact  OD measurement of the shaft were  the Oring sitting in the clutch basket  

if not will need to go and buy a set of bent leg calipers to get the measurement

The OEM part is an o-ring with an i.d. of 19mm and a thickness of 4mm.

RicK G wrote:The internal diameter should 18mm and thickness 4mm so the lower one is not right.

Yeah I'll correct that, sorry for the bum steer I was running on memory Matt 19mm x 4mm