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Restoring #163

All about BMW in racing can be discussed. Sharing of pictures, and other information.
johnlacko
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Joined: Sat Nov 28, 2020 11:40 am
Location: Toms River, New Jersey
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Re: Restoring #163

Post by johnlacko »

Eric, do you have any close up photos or other details of the 2 top engine mounting brackets that were added to the B&S racers, and how they attach to the 4 studs that were added to the top of the engine (last two photos)? Also, I’ve seen two versions - what looks like a solid one on the restored 163 bike, and a heavily lightened one on the #83 bike (first photo). What version was used in 1976? Thanks🙂
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Ericandchi
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Re: Restoring #163

Post by Ericandchi »

Here is a pic of the brackets as requested. On the cases used there were casting pads for an old style starter motor. The aluminium is thick there so basically drill 8mm holes then locktite in the studs. Pics you posted show the detail.


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johnlacko
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Re: Restoring #163

Post by johnlacko »

Thanks for the photos of the original top motor mount. Mine are definitely replacements. Race bikes are always a snapshot in time! I was finally able to find a clear photograph of the clutch cable/throwout I asked about earlier. When you have time, can you see if you have any photos of how the throwout lever was modified (lengthened) for it to be flipped over? Also any views of how the clutch cable is attached to the frame cross brace. I have the hole in my frame brace to attach the cable, I just don’t know how it was done. Many thanks🙂
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Ericandchi
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Re: Restoring #163

Post by Ericandchi »

Sorry, not gonna be able to help on this one. Clutches on the original race bikes where on the bottom like a stock bike. Whoever made those mods it was long after the bikes left care of my dad.

sherman980
Posts: 81
Joined: Fri Oct 27, 2006 3:00 am

Re: Restoring #163

Post by sherman980 »

John,
While I cant see specifically what was done to the clutch actuating lever, I suspect all they did was cut the long part of the lever off just after the adjusting bolt area and weld it the the opposite side of what was left. That way, pressure on the relocated lever pushing away from the trans (as opposed to stock where the lever is pulled towards the trans) would push in on the clutch release rod. By anchoring the end of the clutch cable solidly to the frame, when the clutch lever is pulled in, the outer sheath of the cable will move towards the end of the cable pushing the clutch actuating lever away from the trans and pushing the clutch release rod into the trans as it should. Sounds a bit counter intuitive, but I've actually used a similar set up in a different situation and it worked just fine. Hope that helps.
Thanks.
Chuck S

johnlacko
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Location: Toms River, New Jersey
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Re: Restoring #163

Post by johnlacko »

Hi Chuck, yes it is counterintuitive, but it works! I saw a similar setup on an NSU racer once. I’m not sure how long they used the setup, but they did use it in the very first race. Here is the April 1976 issue of Das Motorrad, which had an article about the Daytona race the month before. You can see the reversed clutch in several of the photos. From Eric’s comments, the details may have been forgotten since then - perhaps because it didn’t work as expected and it was removed. As you say - some part of a 2nd lever must have been welded on to the original to extend it. These details fascinate me, and I was curious to see how they did it.
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johnlacko
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Re: Restoring #163

Post by johnlacko »

Chuck - I know that you were there racing that first year in Daytona too - Laverda, wasn’t it? Does this this reddish ring hanging around the frame have something to do with the Tech Inspection done on the bikes?
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Werner1111
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Re: Restoring #163

Post by Werner1111 »

What an interesting thread.

John - what is the date on the German magazine with the R90S race bike? You can clearly see the clutch cable mod in that picture and the later picture you posted regarding the red ring. Also, what are you building John? Sorry if I missed it, but I don't believe I saw that in this thread?
R69 R90/6 R100/7 R100S R1150GSA S2R1000

johnlacko
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Re: Restoring #163

Post by johnlacko »

Here is a view of the magazine cover. April 1976. I have an old Butler & Smith R90S racer, and have been following Eric’s story about #163, looking for clues about mine. I’m still not certain of its exact history, and Covid has kept me from getting it in front of Eric’s father Udo for a closer look. It had been raced well into the 1980s, but I’m trying to restore it back to 1976 Daytona race spec, and have it done for BMWs 100th anniversary next year. Since race bikes are always a snapshot in time, it has required a lot of research to get the details right. But thankfully, many of the takeoff parts survived and came with the bike, including the one year only Koni mono-shock conversion. I’m not sure why some photos got turned sideways here, but if you click on them to enlarge, they display properly.
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sherman980
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Re: Restoring #163

Post by sherman980 »

johnlacko wrote:
Thu Jul 14, 2022 7:13 am
Chuck - I know that you were there racing that first year in Daytona too - Laverda, wasn’t it? Does this this reddish ring hanging around the frame have something to do with the Tech Inspection done on the bikes?

John,
That was a LOOOONG.... time ago! LOL! Actually was riding a TZ250 and TZ700 at Daytona that year (I think) and may have run a Kawasaki Z1 in Production class that year (maybe '75?) - I honestly don't remember. I rode Tom Lester's (Lester Wheels) Laverda 750SFC in a number of endurance races around that time, but never at Daytona.

As for the tag, pretty sure that was from Tech Inspection. I remember them tagging bikes, but honestly don't remember the details at this point. Those were exciting times for a young kid! In the excitement, lots has been forgotten.
Thanks.
Chuck S

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