MOTOBRICK.COM

TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: TimTyler on August 12, 2012, 02:54:16 PM

Title: Transmission Mount Shims ??
Post by: TimTyler on August 12, 2012, 02:54:16 PM
I'm re-installing the transmission et al and I'm seeing enough space for a couple of washers between the two frame mounts and the transmission. I'm 99% sure there were no shims or washers there when I took it apart.

Tightening it up without washers (between the transmission and frame) obviously flexes/bends the steel frame a bit.

Should there be washers or shims in there?
Title: Re: Transmission Mount Shims ??
Post by: Scott_ on August 12, 2012, 05:48:22 PM
Well, there are shims for that purpose, but there is also a certain spot where they are supposed to be at.
There is a procedure for bolting the frame to the engine/trans assy, and it tell where the shims should go if needed.
It's from the manual for the 1100's, so I'm not sure if it would totally apply to the k75's or not.
Title: Re: Transmission Mount Shims ??
Post by: Motorandy123 on August 16, 2012, 07:46:00 PM
I have the 20Meg repair manual and it says to put 2 bolts in on one side and
shim something and have less than 0.25 on the other side. It is a PDF and I
don't know how to post one page and it won't let me cut and paste. I believe
you can see it here;
http://www.k100.biz/pdf/OFF/K100_K75_2V_eng.pdf (http://www.k100.biz/pdf/OFF/K100_K75_2V_eng.pdf)
Title: Re: Transmission Mount Shims ??
Post by: TimTyler on August 16, 2012, 08:02:13 PM
Thanks, Randy.
Title: Re: Transmission Mount Shims ??
Post by: Scott_ on August 16, 2012, 10:37:05 PM
..... It is a PDF and I don't know how to post one page and it won't let me cut and paste.

Setup a 'xps' printer on your pc, then from within the Adobe program just print the single page to the 'xps' printer. '.xps' documents can be viewed with Internet Explorer.
That's how I do it at this point.
Title: Re: Transmission Mount Shims ??
Post by: 552255 on August 16, 2012, 10:52:14 PM
Check the MAXBMW schematic, i think there were various thickness' available, which may lead one to believe if there is space after following the tightening procedure, to shim the void.  During a new frame installation, i had a large gap on the last frame/trans. bolt. i shimmed the gap, and things seem fine.  No idea what would happen if you put a bit of tension on the frame by not using some spacers...it may affect alignment slightly?
Title: Re: Transmission Mount Shims ??
Post by: TimTyler on August 16, 2012, 10:53:46 PM
Would a washer be any different than a shim?
Title: Re: Transmission Mount Shims ??
Post by: Rick G on August 16, 2012, 11:15:55 PM
There would be absolutely no difference for that purpose, so long as it takes up the space.
Title: Re: Transmission Mount Shims ??
Post by: Motorandy123 on August 17, 2012, 11:33:10 AM
Yes a washer is a shim just shim denotes you might have different thicknesses available.

Thanks for the tip on the XPS printer. I'll give that a try!
Title: Re: Transmission Mount Shims ??
Post by: frankenduck on August 17, 2012, 04:01:35 PM
FYI: I've disassemlbed lots and lots of these bikes and have never seen a single one that had shims for the transmission mounts.
Title: Re: Transmission Mount Shims ??
Post by: TimTyler on August 17, 2012, 04:05:51 PM
FYI: I've disassemlbed lots and lots of these bikes and have never seen a single one that had shims for the transmission mounts.

Yes - I'll let it be.

The PDF (thx, Randy) seems to recommend using the shims on the front bolts anyway, not the bolts that mount to the transmission.
Title: Re: Transmission Mount Shims ??
Post by: frankenduck on August 17, 2012, 04:08:02 PM
There is one that goes between the top of the bellhousing and the frame.
Title: Re: Transmission Mount Shims ??
Post by: TimTyler on August 17, 2012, 04:20:15 PM
The bolt in the center of this picture is the one that seemed to want a shim.
Title: Re: Transmission Mount Shims ??
Post by: ReneZ on August 24, 2012, 03:27:43 AM
You'll want to fit your frame as 'stress-free' as possible, so I would fit washers/shims to fill up the clearance as good as possible and then tighten it up.

Cheers, Rene
Title: Re: Transmission Mount Shims ??
Post by: TimTyler on August 24, 2012, 10:03:16 AM
Where should I support the bike/frame in order to R&R that bolt?

When the bolt was out last time, the frame was supported by saw horses and the power train and rear wheel were removed.
Title: Re: Transmission Mount Shims ??
Post by: Lawrence on August 24, 2012, 08:30:37 PM
I believe I read a BMW service bulletin that addressed these shims.  It was related to quelling engine vibes and specified detailed procedures for shimming and torquing the fasteners.
Title: Re: Transmission Mount Shims ??
Post by: frankenduck on August 24, 2012, 08:39:55 PM
Where should I support the bike/frame in order to R&R that bolt?

If you're just doing one bolt at a time then you probably don't need to do anything special. That's what I'd do. (Actually I wouldn't bother with shimming it in the first place.)
Title: Re: Transmission Mount Shims ??
Post by: TimTyler on August 24, 2012, 08:57:31 PM
I believe I read a BMW service bulletin that addressed these shims.  It was related to quelling engine vibes and specified detailed procedures for shimming and torquing the fasteners.

I found this bulletin (https://www.bmwmc.net/catalog/2163.pdf) on this bulletin list (https://www.bmwmc.net/bulletinsearch.asp?A=1&C=4&OB=datestart). Probably does not apply to me though.

Maybe this one. (https://www.bmwmc.net/catalog/2234.pdf)

I'm with Duck though. Will probably just leave it the way it's been for probably 21 years.
Title: Re: Transmission Mount Shims ??
Post by: frankenduck on August 24, 2012, 09:58:08 PM
And there's also the issue of getting the trans out of alignment with the bellhousing - leading to potential premature spline death.
Title: Re: Transmission Mount Shims ??
Post by: TimTyler on August 24, 2012, 10:11:26 PM
And there's also the issue of getting the trans out of alignment with the bellhousing...

My bellhousing has the alignment shims that assure the transmission is mounted straight.