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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => Project Classic Motobricks => Topic started by: BoardOfCan on August 29, 2023, 12:39:57 PM

Title: My white (black) whale: a clean 1991 K100RS, ready to be chopped to bits!
Post by: BoardOfCan on August 29, 2023, 12:39:57 PM
And by "chopped to bits" I mean no chopping whatsoever. It's too clean and I cant stop drooling over it and then realizing it's MINE.
(https://i.imgur.com/BEiKznS.jpg)
Yes, the mirrors and belly pan are in the garage. I bought it "non-running" from a couple guys who did, to their credit, replace fuel pump and filter, injector$, spark plugs, and air filter and still could not get it started. I bit it anyway because it has 40k on the (still functional) clock, and has been sitting in dry storage since 2007. Cleaning the fuses, all electrical connections, and plugging in the fuel pump (after a thorough flush of the tank and internal lines), it started after cycling some fresh gas through a little. Both brake master cylinders are dry and crusted, coolant filler and overflow are dry but not crystalized. So the plan for now is all fluids, brake lines, probably rebuild kits for both master cylinders (I'm optimistic but not THAT optimistic, but we'll see), tires, a careful look at breather tubes.
I'm not asking for a checklist, there are plenty of posts with solid advice to reference. The 2 flaws are that a) both weep holes under the engine have residue, not dripping but not dry. What is the threshold where one worries about that residue? What are the chances seals need replacing? AND! b) Paint isnt perfect - during its time in storage it got some dings. It's the most beautiful metallic black, seemingly full of greenish and bluish flakes, the paint code under the seat is 670. I'm assuming it's the classic black, does anyone have a good source for touch-up paint?
This is only a little silly because I already have a perfectly decent (if weary, but loved) K1100. But hey, if any group of people understands the obsession, I'd hope it would be you folks. Wish me luck!
Title: Re: My white (black) whale: a clean 1991 K100RS, ready to be chopped to bits!
Post by: The Mighty Gryphon on August 29, 2023, 12:50:16 PM
Nice looking whale you have there.  Do the belly pan white and you'll have the only Orca in Massachusetts.

I wouldn't bother with a rebuild kit for the rear master cylinder.  There is a thread here that outlines replacing it with a very reliable Chinese Commie unit for under 20 bucks. 

And be advised that "Moby Brick" and "Moby Brick Too" have already been taken.
Title: Re: My white (black) whale: a clean 1991 K100RS, ready to be chopped to bits!
Post by: Laitch on August 29, 2023, 01:30:18 PM
And be advised that "Moby Brick" and "Moby Brick Too" have already been taken.
Willy and Keiko are still available though.  112350
Title: Re: My white (black) whale: a clean 1991 K100RS, ready to be chopped to bits!
Post by: BoardOfCan on August 29, 2023, 01:31:44 PM
OK but is CALL ME ISH-K-AEL available?
I got fed up trying to get a $20 chinese one to work well on the k11 and ended up getting a Magura 11mm that worked even worse.
Title: Re: My white (black) whale: a clean 1991 K100RS, ready to be chopped to bits!
Post by: Chaos on August 30, 2023, 02:16:01 PM
Not sure if it will help or not, but I had excellent luck with my front and back master cylinders by just taking them apart and cleaning them.  The seals were still intact and probably just had some crud in them that stopped them from sealing, and I cleaned up the bores a little.  I did the front when it started leaking about 6 years ago, the back just last year, and both were fine when I sold the bike last June. 
Title: Re: My white (black) whale: a clean 1991 K100RS, ready to be chopped to bits!
Post by: BoardOfCan on August 30, 2023, 02:21:29 PM
If nothing else it is very reassuring - given the cost of rebuild kits, I'm more than happy to strip, clean, and verify before renewing. The only mild bummer is that the boots on both (true on my K11 too) ware totally stretched out and useless. But for sure, the front mc is laid out on my bench right now, soaking a bit to try to free up the stuck piston.
Title: Re: My white (black) whale: a clean 1991 K100RS, ready to be chopped to bits!
Post by: Chaos on August 30, 2023, 02:27:54 PM
yeah, I was lucky mine weren't too far gone.  My dust boots were shot also, found some close-enough replacements I had lying around, I think one of them was an old clutch-rod boot from the Ural  :laughing1:
Title: Re: My white (black) whale: a clean 1991 K100RS, ready to be chopped to bits!
Post by: Laitch on August 30, 2023, 05:53:42 PM
The only mild bummer is that the boots on both (true on my K11 too) ware totally stretched out and useless.
It might be worth inquiring at Max BMW to determine if the lower entry for item #8 is available. It seems it could be an aftermarket part. Usually, if a price is attached it's available although perhaps not immediately.

Title: Re: My white (black) whale: a clean 1991 K100RS, ready to be chopped to bits!
Post by: BoardOfCan on August 31, 2023, 11:36:48 PM
I dont think I could go on without the Max parts fiche. For part numbers, anyway. Both master cylinders are seized up good with old dried brake fluid and soaking overnight, fingers STILL crossed!