The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: jakebass12 on August 04, 2012, 11:58:30 AM

Title: ring gap for pistons
Post by: jakebass12 on August 04, 2012, 11:58:30 AM

hello i found this link (http://www-cdr.stanford.edu/~petrie/bmw/R80ST/engines.html) about the ring gap and it also has some other stuff. i was wondering if the sizes are the right ones.

Title: Re: ring gap for pistons
Post by: nhmaf on August 04, 2012, 10:58:07 PM

Quite alot of info there - though I have seen some of the same tables (I think that they were the same - at least they had the same font, spacing, etc.) on another website before.

I hadn't known that some of the ranges of ring end gaps were so wide - I seem to think that .0120" was the typical/ideal value, which would be toward the minimum end of the range in this chart.

Title: Re: ring gap for pistons
Post by: tvrla on August 05, 2012, 09:48:27 AM

Installing new rings?

Seems like .010" is pretty standard. When I recently re-ringed the 850 R65 with the same pistons and only slight honing, I set the gaps to something like .007". I was a little concerned about the rings possibly seizing, but it all worked out fine.

I used this data and swear by it:

http://www.mototuneusa.com/break_in_secrets.htm