The owners manual for an 06 and 07 YZ 125 calls for a ring end gap of 19 thousands for a new ring. Is this a misprint ? Using the bore diameter vs ring expansion rule of thumb I would guess the gap should be about 8/1000.
That is probably correct. Wiseco calls for .004 per inch of bore size. On my sons KX100 that came out to be about .0084
52.5mm bore divided by 25(25mm in an inch)= 2.1 inches
2.1 x .004 = .0084
My ring set actually had about .011 or .012 and Eric Gorr told me that it was good to have a little bit of extra clearence to compensate for heat expansion and that the .0084 would be the minimum recomendation.
So without knowing the exact bore size of your machine but knowing it has a bigger bore I would say that your manual is probably correctly stating the ring gap at .019. Either way you could probably use this formula and get pretty close. I don't know if the OEM rings have a different spec than Wiseco does or not, that would be the possible variable.
I'm sure others on this forum could give more input on this and shed more light on this topic.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
