bandersnatch
New member
Hi everyone,
Larry here from Hillsboro, Oregon. Over the Fourth of July I drove to the Seattle area and brought home an orphaned and neglected 1975 BMW R90/6. Since its arrival in my garage I have overhauled the carbs, cleaned and flushed the gas tank, replaced the fuel petcocks and lines and replaced the battery, points, choke cables and spark plugs. I also disassembled and cleaned/greased the throttle hand grip and the choke assembly.
The last plates are from 1995 and the bike was last registered in 1992, so it appears to not have been on the road for almost 25 years. After the above work and setting the timing, the bike now starts easily although I'm still working on getting it to run without the choke.
My question is this. As several others have experienced, the mechanical advance retaining nut was broken off leaving me with the choice of replacing the camshaft or drilling it for a retaining screw. As I'm just trying to get the bike running for a bit before a complete teardown and restoration, my preference was to try modifying the existing camshaft. To my amazement I found a previous owner had already drilled a hole down the center of the camshaft.
I filed the remnants of the retaining threads off smooth with the face of the advance plate and per some instructions I found on this site, proceeded to drill it out in one drill size increments up to 11/64" then tapped the hole for a 5x.8mm thread. When i inserted a bolt with a lock washer, I found it very successfully locked the advance mechanism in place.
Now to the issue I'm having. While the advance appears to be holding really well, I'm concerned that it may slip as the remaining nose (round with a locating flat) was pretty buggered up as if someone ran the bike with the advance loose on the shaft. I can rotate the advance mechanism counter-clockwise about 30 degrees from the original location.
My thought was that since the advance mechanism has two apparently identical lobes to open the points, would it be feasible to file another flat opposite the original flat in order to lock the advance firmly into one position? Based on the amount of adjustment in the points plate it seems like it wouldn't have to be perfect, just close.
Any thoughts or recommendations would be very much appreciated.
Regards,
Larry from Hillsboro, OR
Larry here from Hillsboro, Oregon. Over the Fourth of July I drove to the Seattle area and brought home an orphaned and neglected 1975 BMW R90/6. Since its arrival in my garage I have overhauled the carbs, cleaned and flushed the gas tank, replaced the fuel petcocks and lines and replaced the battery, points, choke cables and spark plugs. I also disassembled and cleaned/greased the throttle hand grip and the choke assembly.
The last plates are from 1995 and the bike was last registered in 1992, so it appears to not have been on the road for almost 25 years. After the above work and setting the timing, the bike now starts easily although I'm still working on getting it to run without the choke.
My question is this. As several others have experienced, the mechanical advance retaining nut was broken off leaving me with the choice of replacing the camshaft or drilling it for a retaining screw. As I'm just trying to get the bike running for a bit before a complete teardown and restoration, my preference was to try modifying the existing camshaft. To my amazement I found a previous owner had already drilled a hole down the center of the camshaft.
I filed the remnants of the retaining threads off smooth with the face of the advance plate and per some instructions I found on this site, proceeded to drill it out in one drill size increments up to 11/64" then tapped the hole for a 5x.8mm thread. When i inserted a bolt with a lock washer, I found it very successfully locked the advance mechanism in place.
Now to the issue I'm having. While the advance appears to be holding really well, I'm concerned that it may slip as the remaining nose (round with a locating flat) was pretty buggered up as if someone ran the bike with the advance loose on the shaft. I can rotate the advance mechanism counter-clockwise about 30 degrees from the original location.
My thought was that since the advance mechanism has two apparently identical lobes to open the points, would it be feasible to file another flat opposite the original flat in order to lock the advance firmly into one position? Based on the amount of adjustment in the points plate it seems like it wouldn't have to be perfect, just close.
Any thoughts or recommendations would be very much appreciated.
Regards,
Larry from Hillsboro, OR
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