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Differential timing issue
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Differential timing issue
Does anyone have an idea of what I am doing wrong here? I have a 1965 R50/2 that I built successfully, so this is not my first go with an old BMW.
Any ideas appreciated.
Dave Fish in PA
1965 R50/2 (now sold)
1958 R60 (project) Now running well
1973 R75/5 (recently sold)
1956 R26 (basket case project)
- Rodolfo850
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Re: Differential timing issue
I just has same issue on my R60/2 few weeks ago, I wasn't able to correctly fit time.
Magneto time was correctly set, point gaps set, but can't make test Buzzer lights when flywheel shows S on mark.
When making a running timing test, S appears on upper side of window (too Advanced), but points didn't go far enough to retard time a little.
Even moving magneto body( knowing that will weak spark) didn't make any difference.
After three days I started to make some test with point gaps, while measuring find that point gap changes between engine rotations, meaning differential timing is affected by point gaps. Checked with a Dial indicator and all its OK...
Until removed ignition point and find that pivoting bushing isn't concentric, with a 0.10 mm of runout on middle, so at some point rotated perfect with a bore of 4.00 mm but when hits oval part of bushing diameter increases to 4.10mm which causes a reduction of point gap, causing problems on timing.
After installing a used set of Bosch ignition points, everything works great!!
Start by changing ignition points set and check again..
regards
Rodolfo
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Re: Differential timing issue
Thought that maybe it was the advancer, so took one off my running R50. Installed on the R60, but acts the same.
Suggestions are welcome.
Thanks in advance.
Dave
1965 R50/2 (now sold)
1958 R60 (project) Now running well
1973 R75/5 (recently sold)
1956 R26 (basket case project)
Re: Differential timing issue
chuck
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Re: Differential timing issue
R69S - R60/2 - R67/2 - R51/3 - R69
- jwonder
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Re: Differential timing issue
If this is a replacement advancer they have been known to be bad and I had a very bad one that was new. The reproductions have been bad for a while and I am not sure when they were introduced! Please see a video I made on the issue and it clearly shows the height is close, but the ramp starts in the wrong area. viewtopic.php?f=7&t=16364
Now, if it is an original unit I would be surprised if the ramp was worn, but if proper lubrication was not used throughout its lifetime it could certainly be worn, and only one lobe, not both. It is possible.
I hope this helps!!!
Vice President, Vintage BMW Motorcycle Owners
2022 BMW Friend Of the Marque
Long Island, New York
Re: Differential timing issue
Dave
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Re: Differential timing issue
Hope that helps.
Chuck S