R100 right side clack

[salty]

I'll pull it apart again this weekend. I'm pretty sure they're good.
If those heads fit - I'm in as they're complete

S

[George Ryals]

The later heads may bolt onto the earlier barrels, but the later heads may be designed fro a different piston crown profile.

8. High compression pistons may have problems with the head. Later pistons had the dome extending to the edge; later 1970's types with the squish band were designed to work with a matching cylinder head, & might have to be machined. This might occur with some modification you are attempting, such as later pistons fitting 1977 heads. The squish pistons used on such as the 1977 R100RS are hard to find. The original 'squish' pistons are no longer available. One can modify the head & cylinder (deck height change, about 0.050") and thereby get your own squish pistons in practical use. The 1977 year was different regarding the pistons. The 1978+ had a different shape for the pistons...at the edge as an example. The 1977 style pistons are probably no longer available. Perhaps some PRE-emissions 1978 pistons will work, but you would have to order them & look at them. The 1977 R100 pistons were special, only used in that year & model. If you have a 1977 R100 & need pistons, you could consider using the 9.5:1 1978 pistons with the outside circlip.

copied from: http://bmwmotorcycletech.info/pistons.htm