Ring gap? 2001 xc300

[motogroove]

Hi there,

I'm ready to assemble my 2001 xc300 top end. I have my cylinder just back from being replated by Langcourt's. They did a nice job. I have an Athena A size piston kit. I sent the piston, but not the rings, with the cylinder to Langcourt.

If I drop a ring into the bore to check ring gap, I am seeing about .014 or.015 inch ring gap (.36 or .38 mm). That looks pretty tight to my untrained eye, and I don't have a gap spec to check against.

I just wonder if I'll run out of gap when the engine gets hot.

Thanks in advance for a clue or two.

-Dean
2001 xc300

 

[stainlesscycle]

manual says

300 cc: STD: 0.5 mm - Limit: 0.8 mm

it may be different with athena pistons - i know wiseco uses a different spec.

this .5mm/.8mm gap spec seems awful big to me.

 

[motogroove]

This from Athena:

"Hello,

The difference 0.01 to 0.03mm (0.35 →.38 )in the ring end gap of the rings doesn?t affect the performance of the engine.

The clearance piston-cylinder wall that we use is from 0.04 to 0.06mm

Thank you"

 

[dirtbikefool]

rule of thumb on most engines is .004'' gap per inch of bore.