K11 Owners Group

MCRyder · Posted: Fri Feb 08, 2008 10:54 am Post subject: Trans Fluid Viscosity

I'm switching over to synthetic for the transmission and final drive. The K11 manual shows using 80 or 90 weight, or 80W90. The only synthetic I can find is 75W90. Any issue with using the 75W90?
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Mark Rooney
Tyler, TX
'93 K11RS
http://community.webshots.com/user/zgryder

John Clauss · Posted: Fri Feb 08, 2008 11:05 am Post subject:

Thats a very slight difference. 75W90 should be OK.
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1997 K1100LT
1975 R75/6

It will bring you so close to nausea, it will make you sick! - Big Al

rkildu · Posted: Fri Feb 08, 2008 1:29 pm Post subject:

I have been running 75W90 Mobil 1 in both my 82 Airhead and my K11 for a number of years. No problems.

Rod

Flying Duck · Posted: Fri Feb 08, 2008 1:44 pm Post subject:

I run Mobil 1 75/140 in my trannies, 75/90 in the final drives.
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93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
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6899 · Posted: Sun Feb 10, 2008 2:19 pm Post subject:

I run Mobil 1 75W90 synthetic in both tranny & rear drive. There has been some discussion about use of the 75W140, and I don't want to go there. I just follow the book specs. So far its worked. Got 97K out of my R100/7 tranny......but should have replaced the bearings at 60K per Oak Oakelshen. In my case, at 97K the 3rd and 5th gear were worn out - a common problem in older airheads.

My take ---follow the manual for specs. Love the synthetics; I run 15W50 Mobil 1 in my engine. Overall, the tranny is quieter with the synthetic.

Martin Razz

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1996 K1100LT, 73K (bought at 61K on 2006)
1977 R100/7, bought new, rode 97K in 29 yrs before parting out
1970 R50/5, bought used, rode 40K & sold

BMWMOA #6899 since 1976
Indy BMW Club since 1975

BMGraeme · Posted: Sun Feb 10, 2008 5:43 pm Post subject:

The gearbox is about the only thing I dislike about my K - it's agricultural and notchy at the best of times. Upshifts are liveable with as long as you preload the gear lever but I have to blip the throttle on downshifting to get a good solid selection. I greased the splines last year (including the clutch input spline) and they all looked like new. The gearbox has only 22K on it like the rest of the bike and I have been using mineral oil up until now. Will a move to synthetic in the gearbox help with the feel of selection? There has been talk about seals leaking with synthetic oils - is this a worry with the tranny?
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1980 CB900FA
1994 K1100RS
2008 R1200GSA

Tim (Midland Section) · Posted: Sun Feb 10, 2008 6:27 pm Post subject:

6899 · Posted: Sun Feb 10, 2008 10:10 pm Post subject:

The synthetic definitely helped my R bike. I don't know what I had in the K when I got it, but here is a suggestion.

Try it! Its cheap insurance. What do you have to lose? $20?? The tranny is worth more than that. Wink

Most of the BMW riders I know use synthetic in the tranny. With a water cooled engine, you can get away with dino oil.

Martin
_________________
1996 K1100LT, 73K (bought at 61K on 2006)
1977 R100/7, bought new, rode 97K in 29 yrs before parting out
1970 R50/5, bought used, rode 40K & sold

BMWMOA #6899 since 1976
Indy BMW Club since 1975

BobZ(IL) · Posted: Mon Feb 11, 2008 12:15 am Post subject:

My K has been treated to synthetic fluids since 600 miles (now at 48k). Never a problem, leak, etc.

R bike fluids have always been dino, no lube problems there either except pushrod seal leaks. R trannies take a bit more finesse to shift, maybe I'll try a synthetic.
_________________
'93 K1100LT
'78 R100S
'05 R1200GS
BMWMOA, CRBMWOA, ABC, K11OG #997

Live well, do good work, enjoy the ride.