The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Landlubber on May 24, 2010, 10:31:24 PM

Title: Piston ring end gap
Post by: Landlubber on May 24, 2010, 10:31:24 PM
Hi peoples (and others),

As I am rebuilding my little puppy (R65LS), I have the engine on the bench and the heads and barrels off.

I slipped a ring into the bore and the ring end gap is 6mm......yep, thats right, not a typo.

Has anyone ever seen this before...it was my belief that the engine has never been apart. Before I stripped the bike I did ride it around a bit, and it seemed to have about the right amount of power (50 hp, same as my R80), so wondering why the gap could be soooooo large. The bore is looking very good.

Ta, John
Title: Re: Piston ring end gap
Post by: Mike V on May 24, 2010, 10:52:39 PM
John,

That's pretty wide. Are you sure it's not broken? How about the other two rings?

Ring gaps should be...0.012” (0.30mm) to 0.020” (0.50mm) for the two top rings and 0.010” (0.25mm) to 0.016” (0.40mm) for the oil ring.

Title: Re: Piston ring end gap
Post by: nhmaf on May 25, 2010, 11:12:27 AM
Practically a quarter of an inch seems excessively excessive. :D
Title: Re: Piston ring end gap
Post by: Landlubber on May 28, 2010, 11:58:02 PM
I simply do not see how the bike has such a large ring gap, yep the other side is the same gap too....never see such a thing.

I guess it simply is so, will need to re ring the poor thing.

Such is life.