02 K12rs Final Drive Leaking - K-Bikes.com - Excellence in Motion
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post #1 of 33 (permalink) Old Apr 13th, 2008, 10:21 pm Thread Starter
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02 K12rs Final Drive Leaking

OK, it's happened to me. I've read the horror stories in here about the $1200 + repairs and now it's my turn to face the problem full on. It started at the end of the riding season last year and is just a little crud showing up on the bottom side of the final drive just in front of the rubber boot (very impressive design work with it's plastic clamps btw... ) and sometimes a couple of drops of oil is noticeable. I showed the senior mechanic at the local dealer (where I bought it used), and he said it should be opened up and repaired. He hopes cost will be $400 at the most but of course depends on what they find.

A question I would like to pose is has anyone just left it alone and continued to drive it? If so, what has the experience been?

I stored it in my basement over the winter and just thought about the situation. Like many of you I am torn between bitter dissapointment that after longing (lusting) for this bike for so many years - driving inexpensive but reliable Jap bikes, then taking the plunge on the object of my desire only to be bitten in the proberbial ass by it. I absolutely love riding the bike but hate the nagging thoughts of "is this just the start of a possible list of expensive repairs". I have an appt. with the repair shop for April 30th but find myself searching the classifieds at various online sites for non BMW bikes. I have a 5 - 6ooo miles trip planned for this summer (upstate NY to Denver, tour Colorado and Wyoming then drive back home) and I have to be at least reasonably certain it can make the trip.

Please don't remind me that anything can break down - I know this - it's just that certain model bimmers (mine) seem to have a worse track record than most other brands.

Do I leave it alone and hope for the best (I have driven it several hundred miles since first noticed and doesn't seem any worse)? -OR- Do I put it under the knife and hope for the best and maybe just leave my credit card at the dealer for easier future transfusions into their vacation account? -OR- Do I sell it now and hope for the best with some other brand?

Last question: How the hell can a company with arguably the best and most creative engineers in the world allow their products to suffer from such widespread problems of seemingly inexpensive parts (like seals)???? Perhaps just a matter of poor quality control undermining brilliant engineering? Whatever it is, I'm not happy - do they care????

Thanks for listening to yet another K12RS rant - I just wish I'd found this site before plunking down my hard earned money................

Moosedog is shaking his head.......
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post #2 of 33 (permalink) Old Apr 14th, 2008, 8:59 am
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I had the same problem. I just did some tests, worked out a plan to do other jobs and fitted it in. I'd already made up some stainless bands for the boot, although I hear the LT one's are stainless and they fit. I think the bike would have gone ten K with the same amount of leak.

The tests: You don't know yet if oil is coming from the rear drive pinion seal (now that is a PITA to attempt yourself) - or if it's coming down the swing arm from up front (tranny seal). If the front boot on the swing arm has come uncoupled, it might even be oily water!

I did find a way to pressure test my RD and confirm oil wasn't coming from it, by elimination I had the swing arm off and replaced the tranni shaft seal.

Before concluding doom and gloom, I'd pull the boot back and thoroughly clean/degrease everything right up to and inside the swingarm as far as you can get in.

Keep a check on the RD and tranni oil levels and lift the boot after some riding to see which direction oil is coming from. While you're at it, check the RD bearing for any play at the wheel shaft. Often you can be lucky (or unlucky whever way you see it) and more than one problem tips the scales to justify work and how soon it should be done.

I wish I could have got some of that oil dye so I could have reached a diagnosis easier.

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post #3 of 33 (permalink) Old Apr 15th, 2008, 5:42 pm Thread Starter
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Thanks, Vox. I pulled the boot back and cleaned as much as a could get to. Also cleaned all the gunk off the underside of the final drive. Took it out for a 60 mile spin this afternoon and not a speck of dust, oil or grunge anywhere. I'll be riding much more this week (we are blessed with great weather this week) and will report back.

My fingers are crossed.
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post #4 of 33 (permalink) Old Apr 16th, 2008, 7:47 pm
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That leak can also be caused by overfilling the tranny or final drive.

'04 GT...Orient Blue...Staintune...Ohlins...Power Commander
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post #5 of 33 (permalink) Old Apr 16th, 2008, 8:02 pm
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I have a2004 K1200GT that I love but at 14000 miles had the front tran seals leaking. the dealer fix it but charge me for the clucth.550.00. I will not buy any more bmw bikes. I alway had jap bikes and no leaks or anything else go wrong. So the low cost jap bike are better than high price bmw.
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post #6 of 33 (permalink) Old Apr 17th, 2008, 5:12 am
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Mmm..... I had an old Kawa shafty for 60K miles and never any rear drive problems. Always thought shaft was one of those parts you never had to think about.

But then the KAWA rear was dual shock and axle with good luggage load weight - not the rear monoshock with all that wheel side thrust on one bearing. I suppose the benefit of faster safer riding round twisties of a sport bike has to be seen against the higher stresses put on the rear drive.

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post #7 of 33 (permalink) Old Apr 23rd, 2008, 9:09 pm Thread Starter
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I pulled the boot back and completely off the tranny side tonight (broke that damned plastic tie clamp of course) and looking up the shaft it is completely clean. Yet I am still getting a small amount of oily crud (smells like dino oil) that appears to be seeping out at the boot on the bottom of the final drive on the tranny side. I thought for sure it would be a failed seal from the tranny side but how could it be if everything inside is squeaky clean???

So it must be coming from the final drive side - right? One would think, but I checked the final drive oil level and it is full (level is at the bottom of the threads where I'm told it is supposed to be). Where is the oil coming from??? It seems like a small amount which combines with road dirt and dust and creates a grunge like substance.

Thoughts, comments, suggestions, shrugs???

Moosedog is confused..........
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post #8 of 33 (permalink) Old Apr 23rd, 2008, 11:03 pm
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I solved this problem by rechecking oil levels, I had overfilled. But you have already been told that.
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post #9 of 33 (permalink) Old Apr 24th, 2008, 3:53 am
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This is kind of the situation I was in, not knowing whether it was a tranni seal or RD seal leak.

If you have no play on the RD bearing (wheel shaft), then you are probably like I was, curious, slightly annoying but chances are it's not going to let you down just yet. One of those things that sometimes has to get a lot worse to tie down.

I had no choice but to investigate as I was stripping bits off the bike and needed to plan ahead of time.

I looked into oil dyes. I think somebody in the States does them. We have a supplier who sells a flourescent dye (you can spot with a disco UV black light). Unfortunately, I had the light but they sold the dye in large quantities to workshops. I wondered afterwards about just putting a teaspoon of Flourescene in the oil but I don't think it's soluble in oil. If you can get some oil dye, or change the RD drive for a colored oil different to the tranni, then that would be my approach first.

Then I realised that the RD is effectively a sealed unit if you plug the vent on the top. I used a water gauge and pumped up the RD with a cycle pump to about 10 inches of water pressure (small). Then slowly rotated the drive and watched for any pressure drop - there wasn't. Then I left the drive for 10 minutes and rechecked the pressure level - no drop so leak is from tranni - cute method yes?

Since I decided to strip the RD to replace the bearings and seals anyway and the tranni was coming off for clutch and other things, I just did the lot and there are no leaks now. I did do my pressure test on the RD on the bench though before I put it back.

One thing you could check is the dust filter vent. The RD produces some back pressure as the gears run. If this gets blocked then back pressure could increase the chances of a seal leak. There's a crappy piece of foam in there. Mine was missing (pushed in too far) so that wasn't my problem, although I vagely remember thinking the vent hole in the plastic peg was small, so I drilled it out a bit.

Don't worry too much at the mo. if it's a small leak, just be curious. The things to worry more about are a leak at the bottom of the clutch casing (clutch/main engine seal) and the RD final bearing.

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Last edited by voxmagna; Apr 24th, 2008 at 4:02 am.
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post #10 of 33 (permalink) Old Apr 24th, 2008, 8:55 pm
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Dye Source

Carquest sells small 1 oz bottles of the dye and a black light for less than $10.00. The dye is compatible with transmission, engine or rear end oil. Put ia 1/2 oz, go ride a tank of fuel and then check with the black light. I've used a couple of times and it takes the guess work out.

99 K1200RS
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