took apart the 250 due to the fact it was hard starting and had a low compression test. the inside of the cylinder looks like new not a scratch. piston that was inside was a WISECO 642M06700 and looks good also which is standard bore of 67.00mm ..but the rings seem to be sloppy . out of the 2 rings if i put it in the cylinder seems sloppy .here is my ? if i put a new top end /piston/rings /etc/.will i be ok .i did put a magnet indide and it does stick so i would say its a Cylinder Sleeve. just dont want to put this back together and in a week it wont run .. strange how the rings went bad ..piston /Cylinder/head /look real good compared to most i have took apart over the years..i do have digi micromerter. do i need special tool to check for ring end gap. one ring in opening when in cylinder almost touches .the other ring has much more of a gap .. thx for any info.. :ride: :ride: :ride:
Sleeves wear more than plating, maybe plating the sleeve would be a great idea if that is not what you got there on your cylinder. So far I know there is a tollerance allowed in the ring gap.
you measure ring end gap with a feeler gauge, and on the old rings, don't bother, they're worn out.. Measure the new rings to make sure they don't bind when installed.
if its been sleeved it will chew rings faster than a coated bore. measure up the bore piston and old rings.
if it is sleeved and its out of the tollerance you can fit a overbore verry easily as its a steel sleeve, if its coated and in good nick a mega light hone to take the glaze of and a new piston and rings and shes good again. the hard starting is more likely reeds id say get some pics of your bore up for us to see