Very Bad Oil Leak!!!!!! K100RS

[John J Redmond]

I need some serious help ASAP. I redid my K100RS-paint and a bunch of other stuff, one was replace the leaking rear main engine seal. It is leaking more now than before!!!! I folliwed the instructions to the letter and have done many seals on cars and mototrcycles. What could I have done wrong?? Are there any new instructons/replacemnt proceediures? It is a pain in the butt to do and it is ridding season!!
Please email me or better yet call collect or leave return number,email number and best time to call you.I have oredered the seal and oring. Thanks for any help.
John
970-243-8464 home 970-986-1812 cell
Anybody have magic wand? :D

[bmwmick]

John,
Did you follow the manual? The seal is not set flush with the back of the block, http://www.ibmwr.org/ktech/mainseal1.gif When I installed mine, I just used a .020" feeler gauge around the edges to keep it from going in too far.
http://www.ibmwr.org/ktech/mainseal.shtml
My only problem was the O-Ring, my rear seal looked like new as did the tranny input shaft seal but while I was in there THAT far.....I just HAD to replace em both. :stick

[John J Redmond]

Yep went exactly by the manual-Flush. Well I have a new seal on the way and will leave it out .020 as per your information Thanks.
John

[scootrp125x]

Is it the rear main seal that is leaking when oil leaks from a small hole underneath the engine towards the rear of the engine, just above where the center stand is? I just noticed a drop of oil on the garage floor and investigated to find what I think is the weep hole I have read about. I am not technically inclined. What does something like this cost to have fixed? It sounds big!

[bmwmick]

Is it the rear main seal that is leaking when oil leaks from a small hole underneath the engine towards the rear of the engine, just above where the center stand is? I just noticed a drop of oil on the garage floor and investigated to find what I think is the weep hole I have read about. I am not technically inclined. What does something like this cost to have fixed? It sounds big!

Scoot,
It could be the rear main seal OR the $.69 cent O-Ring like mine, or the tranny input shaft seal. Once you KNOW it's engine oil, it can drip for thousands of miles before it will soak the clutch disc but it will in time.

I think the dealers quote about 8 hours plus parts. Figure $300 or so for parts.

[Bobmws]

John,
As Mick said, there is an O-ring that should be repladed too, It is under the big nut in the end of the crank.

Scootr,
A drip can be from either the rear main seal, or the transmission input shat seal. Either one requires removal of hte transmission. There are some good tech articles on the IBMWR tech site that will give you an idea of what is involved. Frankly, If I were to go in there I would replace both seals, and also the tranny output seal. Th elabor is in removing the tranny to get to the problem.

[scootrp125x]

Thanks for the tips. What a dissapointment, I just bought this bike a few weeks ago.

[John J Redmond]

Ok Guys here is the up date on the oil seal problem.
The first seal was WRONG. The second seal I installed is the correct one and I letft it out .020. Strange it only leaks a drop or two when really hot and parked on the side stand-go figure :dunno ? I did repalce the other seal and oring too and new break lines because all that moving around put to much preasure on the lines causing a leak in one and a weak spot bulge when the break was applied-ballon effect on the other. It is not really had to do just time consuming gettig all the stuff out of the way. I drilled out a piece of hard wood to tap in the seal and have it stop close to the propper depth. Miced the last few thousandths tapping lightly.
It will run indefitenly leaking-but I hate leaks of any kind.
Next project is getting a thinner fan that puts out more air; hooking a relay to a switch so I can trun on the fan around town and leave it on when the engine is off. Redoing the air cleaner - ram air- and making better ducting/airflow so that the air vents out the side vents-what a concept! :clap
Will have protype done for the Top of the Rockies Rally in Paionia,CO July 18th I think.
John

[scootrp125x]

Scoot,
It could be the rear main seal OR the $.69 cent O-Ring like mine, or the tranny input shaft seal. Once you KNOW it's engine oil, it can drip for thousands of miles before it will soak the clutch disc but it will in time.

I think the dealers quote about 8 hours plus parts. Figure $300 or so for parts.


I had my K75 at the dealer last week and I asked them about the leaking area. The service manager seemed to think it was transmission fluid so maybe I'm not in for the HUGE repair bill, just a smaller one.

[deilenberger]

Ok Guys here is the up date on the oil seal problem.
The first seal was WRONG. The second seal I installed is the correct one and I letft it out .020. Strange it only leaks a drop or two when really hot and parked on the side stand-go figure :dunno ? I did repalce the other seal and oring too and new break lines because all that moving around put to much preasure on the lines causing a leak in one and a weak spot bulge when the break was applied-ballon effect on the other. It is not really had to do just time consuming gettig all the stuff out of the way. I drilled out a piece of hard wood to tap in the seal and have it stop close to the propper depth. Miced the last few thousandths tapping lightly.
It will run indefitenly leaking-but I hate leaks of any kind.
Next project is getting a thinner fan that puts out more air; hooking a relay to a switch so I can trun on the fan around town and leave it on when the engine is off. Redoing the air cleaner - ram air- and making better ducting/airflow so that the air vents out the side vents-what a concept! :clap
Will have protype done for the Top of the Rockies Rally in Paionia,CO July 18th I think.
John
Interesting - how did you find out the first seal was wrong - and where did it come from?

BMW has changed seal vendors for the rear main seal on the K series a few times. Unfortunately - the seal design, specifically the lip height - has changed with the vendors.

It sounds like what caught you was the design change. The newer seal from BMW has a lip that is further in from the outside surface of the seal - requiring you to install the seal with the outside surface not flush with the housing.

If it is installed correctly and the shaft isn't worn - it should not leak. One trick used is to cut the mold flash off the seal - but doing a turn or two on the lip surface with your finger wrapped in 1000 grit sandpaper. The other thing that is important - the seal should be installed with some engine oil on the lip. If not - the lip can burn when the engine starts and you'll have one that drips forever.

As others pointed out - the O ring MUST be replaced. I would replace it even if it looked fine since it can get nicked getting it on and off the shaft.

Be interested in hearing how your fan modification works out. I've never seen a radiator fan that would fit in that space, so if you can find one, I'm sure people will be quite interested.

Best,

[John J Redmond]

Hi Don,
I compaired the seals , from the old to the first one replaced then the last one. The orgional and the last one look the same. I always either greaase or oil seals and some gaskets on one side as required. I did leave it out .020. I do not have any more leaks except from gaskets that will be replaced this winter when I tear it down for balancing and cryogenicing-@$250.
Produces a lot more HP, better fuel milage and runs cooler. Rings eat better than with Nikiseal. I'll also finish up the ram air and proper ducting at that time( I'm not to thrilled about the hot air on my legs when it is 100 degees outside already)
I used a 600 Kawasaki fan-used $20. Wanted to use a 1500 vulcan fan but they cost$465.00 (that is not a typo somebody actual has a more priciey part than BMW) and am still looking for a used one- lots of air. All I had to do was weld a SS bolt on one end and a washer on the other of a 4" ish piece of SS rod. The fan is the thickness of the shroud of the BMW fan. SOOOO much thinner and it does put out more air. Fits right in the same area and has fewer blades to let more air pass through when not in use.

[deilenberger]

Hi Don,
I compaired the seals , from the old to the first one replaced then the last one. The orgional and the last one look the same. I always either greaase or oil seals and some gaskets on one side as required. I did leave it out .020. I do not have any more leaks except from gaskets that will be replaced this winter when I tear it down for balancing and cryogenicing-@$250.
Sounds good - and even when seals are identical, it's not a bad thing to have the lip running on a different part of the shaft - where it isn't worn. The 20 thou isn't enough to make the seal interfere with the back of the clutch basket, but is enough to put it on a fresh part of the output shaft. Good thing IMHO.

Produces a lot more HP, better fuel milage and runs cooler.
What does?
Rings eat better than with Nikiseal.
This is very unclear to me..
I'll also finish up the ram air and proper ducting at that time( I'm not to thrilled about the hot air on my legs when it is 100 degees outside already)
I used a 600 Kawasaki fan-used $20. Wanted to use a 1500 vulcan fan but they cost$465.00 (that is not a typo somebody actual has a more priciey part than BMW) and am still looking for a used one- lots of air. All I had to do was weld a SS bolt on one end and a washer on the other of a 4" ish piece of SS rod. The fan is the thickness of the shroud of the BMW fan. SOOOO much thinner and it does put out more air. Fits right in the same area and has fewer blades to let more air pass through when not in use.
BMW parts prices are very often quite reasonable when compared with the same sort of part on a Japanese bike. No surprise there.. last time I heard a price for the BMW fan - it was well under $100.

Best,

[John J Redmond]

Cryogenic freezing- liqiud nitrogen down to-300 degrees, realines the moliculor structure of the metal. Almost all race cars have it done to the engines and brakes and other critical parts. Here is the number of the company in Ogden,UT 801-395-2796. They do guns too, and they shoot better and the barrel/action will almost last forever.

[deilenberger]

Cryogenic freezing- liqiud nitrogen down to-300 degrees, realines the moliculor structure of the metal. Almost all race cars have it done to the engines and brakes and other critical parts. Here is the number of the company in Ogden,UT 801-395-2796. They do guns too, and they shoot better and the barrel/action will almost last forever.

John, thanks.

I can't imagine what it would do to a K engine (which are known to outlast anyones interest in the bike.. except maybe Paul Glaves, his had over 350,000 miles on it when it was totalled this spring..)

Best,

[dreadedpilot]

I just wanted to thank everyone who posted in this thread. This thread and others like it, which I searched on this forum, have given me the confidence to tear down my bike and fix the leaking main seal on my own. Not only do I save about $800, I gain some valuable knowledge in the process. Thank you for sharing your knowledge and taking the time to unknowingly help a guy in South FL.