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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: mobydick on May 20, 2020, 04:29:25 PM

Title: 1987 K75C clutch throughout bearing replacement
Post by: mobydick on May 20, 2020, 04:29:25 PM
My brick sounds like the bottom end is falling out.  I understand this to be a sound symptom of a faulty clutch bearing. 

There is a new piece on the max BMW part list that combines the old bearing and piston.  Part number 23 13 1 464 167 looks like the way to go but I can't tell if I need replace the control rod to fit up to the new piston????

If I don't need replace the rod it's a lot cheaper.

Also, are the old rod and bushing separate pieces?
thanks for your help
mobydick
Title: Re: 1987 K75C clutch throughout bearing replacement
Post by: Laitch on May 20, 2020, 06:00:50 PM
Much of the text in BMW parts fiches reads like it was translated from German and can be slightly confusing in English. What I believe it means is that if your moto's clutch rod has the bushing (a separate piece #14) indicated by the red arrow in the attached drawing, and if you're buying the new-style clutch piston assembly, you'll need to remove that bushing for the rod to work with the piston; if you're unable to remove it, you'll need to replace the rod with the new-style rod. The attached drawing is of a K100 rod. The K75 clutch rod has a flare near the end where the rod diameter is reduced. I drew a red triangle on the drawing to indicate it but there's a photo of it in the Max BMW fiche (https://shop.maxbmw.com/fiche/DiagramsMain.aspx?vid=51741&rnd=07242017).

If your diagnosis is based only on an understanding rather than actual visual confirmation, you might want to verify the source of the problem before buying parts. You could always post on YouTube a video containing clear audio of this noise, then post the link here. Bricks can make impressive doomsday noises for differing reasons.

Does the noise change when the clutch lever is pulled? Is it a rattle, a grinding sound or a rumble?
Title: Re: 1987 K75C clutch throughout bearing replacement
Post by: mobydick on May 20, 2020, 07:39:45 PM
Laitch
Thanks for the quick reply.  The noise is a rattle and yes, it stops when the clutch lever is pulled. I'll disconnect the clutch cable in the next few days and see what is there. 

I believe the bearing has never been changed and not wishing to pull the tranny hope I find the old style bearing. 

thanks for your help
mobydick
Title: Re: 1987 K75C clutch throughout bearing replacement
Post by: Martin on May 20, 2020, 07:50:32 PM
Bricks came with a standard rattle when the lever was let out (this was a no cost extra). Some were worse than others mine has had a slight rattle for the last 20 plus years. Can you post a sound recording clutch in clutch out, noise can be subjective.
Regards Martin.
Title: Re: 1987 K75C clutch throughout bearing replacement
Post by: Laitch on May 20, 2020, 08:08:27 PM
I believe the bearing has never been changed and not wishing to pull the tranny hope I find the old style bearing. 
Bearings usually grind, rumble, buzz or howl.

Before you go too far, I think you should read this thread (http://www.motobrick.com/index.php/topic,7663.0.html) in its entirety, soon.

Add the year of your moto to your signature and its mileage too; that might give readers a better idea of your moto's condition.

Title: Re: 1987 K75C clutch throughout bearing replacement
Post by: mobydick on May 20, 2020, 09:37:06 PM
Gentlemen (Laitch too) :laughing1:
Monty couldn't have written a better show, "in it's entirety."  It must be the (fe)male side of us being protective of our "babies."  Every time I hear a new noise I'll think back on this topic and have a good long chuckle.

Every thing that's been an annoyance on my brick is forgotten as the kilometers fly past, it truly is a great bike.

thanks guys
mobydick 4265249878
Title: Re: 1987 K75C clutch throughout bearing replacement
Post by: Hilltopper46 on May 21, 2020, 11:53:52 AM
noise can be subjective.

I worked in field service for a farm equipment company for many years. One of my most respected co-workers in those years gave me a piece of advice one which I have never forgotten. "Never admit you can hear a noise unless you know how to fix it."

I'm posting for another reason as well. This is not to be spelling police, but someone sometime may find the valuable information that exists in this thread if searching for a throwout bearing or a throw out bearing (I spent the last several years of my career working with a self-help database for our dealers to find solutions based on symptom searches).