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1966 R69S Advance-Retard

Posted: Sun Jun 20, 2021 12:17 pm
by maddrobh
Some interesting work by a PO. Having a somewhat weak spark, I thought that I'd replace the points & condensor. On removing the A/R unit (allen bolt had been overtightened), I thought I'd compare with the piccies in the Barrington bible to determine which generation A/R unit. Have a look at the photo... I'm surprised how well the bike seemed to run!

Re: 1966 R69S Advance-Retard

Posted: Mon Jun 21, 2021 8:17 am
by Daves79x
The pre-load plates look to be pretty far inward. Might take a while to return to proper idle? What else am I missing?

Dave

Re: 1966 R69S Advance-Retard

Posted: Mon Jun 21, 2021 4:57 pm
by maddrobh
The plates are ‘reversed’, the left hand should be in the place of the right hand and vice-versa (as I understand it from the Barrington manual photos). This causes the springs to rub and bend against the plate. Also, the max advance is not controlled by the steel spring stop but by one of the pillars on which one spring is mounted.

Re: 1966 R69S Advance-Retard

Posted: Mon Jun 21, 2021 7:02 pm
by schrader7032
From the image on Duane Ausherman's site, those adjustable plates look to be properly positioned.

http://w6rec.com/duane/bmw/advance/advance1.JPG

Re: 1966 R69S Advance-Retard

Posted: Mon Jun 21, 2021 8:32 pm
by Jim D 5112
Looks to me like the two pictures have the plates reversed.

Re: 1966 R69S Advance-Retard

Posted: Tue Jun 22, 2021 7:46 am
by Daves79x
From the Barrington book, it looks like the advancer pictured is an early A advancer with two different anchor plates and two different springs. and if the Barrington picture is correct, the one shown here is indeed wrong. Later versions had identical anchor plates and springs.

Dave

Re: 1966 R69S Advance-Retard

Posted: Tue Jun 22, 2021 8:18 am
by schrader7032
Didn't we have a recent discussion about advance units? I seem to remember there were three versions...early on the springs were different sizes and in the end the springs were the same.