The reason I'm posting this is I've been trying for some time to find out the difference in length between R65 pushrods and other BMW air-cooled bikes.
I needed to know this because I'd bought some lightweight cam followers/tappets (made by Wank Racing) thinking all BMW air-cooled twins were the same (a stupid assumption in hindsight).
I had found out through my searching that R65 tappets were different in that the cup contacting the end of the pushrod was placed nearly at the bottom of he follower as compared with the "standard" ones. This was to compensate for the shorter stroke and keep the pushrod angle correct.
The ones I had definately had the cup bit at one end which was quite prominent.
When I asked the place I bought them from (I can't remember now why I thought I needed to do this) they told me they would work fine with shortened pushrods, but didn't tell me by how much.
None of the reference material I could find listed a length, but usually suggested this was "not available".
I thought this was a bit odd if not unhelpful.
To finally get to the point, I ended up buying some second-hand cam followers/tappets and pushrods off EBay so I could directly measure them.
Anyway, they're 288 milimeters long, confirmed Today by a chance finding of a set of pushrods (or Stößelstangen) on EBay.
Hopefully this might prove useful to someone in the future.