Final drive breather

dcstrom

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So I'm reading yet another BMW final drive failure thread on ADVrider (this time it's two at the same time), and talk turns toward the possibility of water/dirt getting into the drive via the breather

http://www.advrider.com/forums/showthread.php?t=711453&page=5

one guy has made a hose so that it can breathe remotely.

http://www.advrider.com/forums/showpost.php?p=16370553&postcount=15

Our bikes have a breather in about the same location - I wonder if too might turn out to be a weak point? Maybe someone can work on a design for a remote breather, just in case?
 

Yamaguy55

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After looking at this, I had the same concern. When I decide to use it for submarine duty, I'll add the vent hose to somewhere up under the seat. There's some photos floating around of a European version going across a fairly deep water crossing. It occurred to me after looking the bike over that I wouldn't do this without a vent mod.
 

sail2xxs

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limey

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Well last Sunday I did use it for submarine duty; Not intentionally, when I got home I changed the final drive oil and there was no water to be seen.
 

Rynn Storm

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limey said:
Well last Sunday I did use it for submarine duty; Not intentionally, when I got home I changed the final drive oil and there was no water to be seen.
Even if a little water did get it, wouldn't it cook off pretty quickly?
 

Koinz

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limey said:
Well last Sunday I did use it for submarine duty; Not intentionally, when I got home I changed the final drive oil and there was no water to be seen.
I haven't looked at the breathing so this is a question. :question:

Is the vent designed to be be a check valve in such that air pressure can equalize but fluids are prohibited somehow.
 

markjenn

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Koinz said:
Is the vent designed to be be a check valve in such that air pressure can equalize but fluids are prohibited somehow.
Yes, but not a very sophisticated one - typically just a labyrinth that turns a direct entry port into something that requires a couple of turns. From what I've seen, the stock system should be fine for anything involving splash or momentary submergence, but not sustained submergence and especially not dumping the bike in deep water. How resistant the final drive it to incidental water contamination? I have no idea.

- Mark
 

3putt

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I have not read those threads you linked to, but from the sound of it, seems about the same problem we had back in the days before "bearing buddy" came out. We would trailer our big boats to fish, get the bearings hot then dunk them in the lake when we launched. It was thought that the water cooled the bearing and sucked water inside. To solve, "Bearing Buddy" to the rescue with a spring loaded grease fitting which would fill the void when it cooled.

I don't plan on doing any water crossings, but I imagine a lot of people that have crossed water did not plan it either.
 

markjenn

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I would guess that only a tiny fraction of S10's see water crossings where water comes up to the breather level for a sustained period - for a bike like the S10 this level of water is going to seem pretty ambitious - personally, I'll be turning around and coming back with my DRZ at a later date. But if you're planning on doing such things, I would be thinking about a remote breather system or at least ASAP changing of the final drive fluid after the episode.

- Mark
 

Twisties

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R 1200 BMW Final drives don't have a breather. Sealed units. Over pressure was the reason for the change to 180 mL fill, from the original 230 mL. That solved one of the many failure modes, seal blow out. Unfortunately a number of failure modes remain, including both lubricated and non-lubricated parts. The 1200 boxer tranny is vented without issue. Oh I see in the threads you linked that late 2010 and after got the vents.... well BMW has been having final drive failures a whole lot longer than that.
 

Koinz

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Twisties said:
R 1200 BMW Final drives don't have a breather. Sealed units. Over pressure was the reason for the change to 180 mL fill, from the original 230 mL. That solved one of the many failure modes, seal blow out. Unfortunately a number of failure modes remain, including both lubricated and non-lubricated parts. The 1200 boxer tranny is vented without issue. Oh I see in the threads you linked that late 2010 and after got the vents.... well BMW has been having final drive failures a whole lot longer than that.
When I changed my gear oil on the Beemer, after the change I would take it for spin to warm it up, then open the fill plug. You would always here a little pffft. I figure that I'd rather have the seals under a little vacuum when cold, then operate under a neutral pressure when riding - I never had an issue with my final drive in 60K miles. Maybe just luck. I also used a pre-mix of molybdenum and gear oil. I'll probably do the same in the Tenere.
 

EricV

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Don't stress about this. Yamaha seems to have this figured out. I've taking the FJR thru extended water crossings, well over the depth of the breather fitting on the diff and never found water or contaminants in the diff fluid in the last 160k. I typically change the fluid every 18-20k. The S10 got Valvoline Synth 75-90 GL5 at 43 miles. And again at 600, and I'll change it again at 4k.

New years day 2011. Must have gone through 1/2 a mile of water over the foot pegs that day at least three times. No water in the diff.
 

Rynn Storm

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Koinz said:
When I changed my gear oil on the Beemer, after the change I would take it for spin to warm it up, then open the fill plug. You would always here a little pffft.
For those switching from BMW to a ST10, the following quote from Yoda is useful. "You must unlearn what you have learned". :) :) :) :) :)
 

Koinz

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Rynn Storm said:
For those switching from BMW to a ST10, the following quote from Yoda is useful. "You must unlearn what you have learned". :) :) :) :) :)
I tell ya, some maintenance on a BMW isn't normal, so it'll be forgotten pretty quickly :D
 

sail2xxs

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I'm looking forward to forgetting the constant trips to the dealer for warranty issues. I'm also looking forward to forgetting about worrying whether the bike will get me home without some sort of mechanical/electrical incident. :D

Chris
 

Rynn Storm

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sail2xxs said:
I'm looking forward to forgetting the constant trips to the dealer for warranty issues. I'm also looking forward to forgetting about worrying whether the bike will get me home without some sort of mechanical/electrical incident. :D
I'm just happy that I don't need to carry a few extra bottles of oil on trips. ;)
 

Mike Sisson

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sail2xxs said:
I'm looking forward to forgetting the constant trips to the dealer for warranty issues. I'm also looking forward to forgetting about worrying whether the bike will get me home without some sort of mechanical/electrical incident. :D

Chris
BLASPHEMY!!!!!!! :D

You KNOW it was how you rode your bike. (you know...turning on the key, starting the engine and putting it in gear........ :D)

That's what the twenty something year old service writer always told me.... the guy who's been riding 45 years and had a least 10 BMW's........:mad:
 

sail2xxs

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DaFoole said:
BLASPHEMY!!!!!!! :D

You KNOW it was how you rode your bike. (you know...turning on the key, starting the engine and putting it in gear........ :D)

That's what the twenty something year old service writer always told me.... the guy who's been riding 45 years and had a least 10 BMW's........:mad:
Don't get me started.... it was my fault that the bike was in the shop for 3 recalls in the first 4k miles (2 months), that the gear shift indicator only ever lasted about 12k miles before crapp;ing out, the oil pressure switch, cooling fan, radiator, fuel tank... oops, I started. :'(

Whatever. 42k miles and basically a year and a half of that was enough. :) Got the S10, and am expecting a minimum of 50K before even minor issues (not related to my stupidity) develop. The 800 GS was my first, only, and last BMW. After 1 Yamaha, 3 Hondas, a Kawasaki and a Suzuki, I would say without reservation that while the GS was fun, it was the least reliable of the bunch by a tremendous margin - more issues in the first month than all the other bikes combined had in 10 years of riding. It was also the most fun. Such is life!

Chris
 

EricV

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Do you do a lot of water crossings? Have you previously found contaminants in your FD oil? And where did you run the hose to, and what's on the end?
 
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