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Other Bikes / Piston ring orientation –use again?
« on: March 11, 2021, 10:59:00 AM »
Hi all, I’m looking for a bit of advice regarding the piston ring orientation on the Kawasaki Z400j I am currently restoring for the BIL.
When I removed the barrels during the strip-down I made sure I didn’t disturb the rings or pistons. Once the barrel was off I took notes of where each piston ring gap was in relation to the piston. I was a bit surprised to see nearly all the ring gaps were very close to each other and in one case, the gap for the top and second ring were virtually on top of each other!
The engine has 380 genuine miles from new and has never been apart, I can only assume this is how the piston rings were installed at the factory unless the rings move in service although I’ve never seen this happen before.
So, the question is and bearing in mind there are still feint honing marks on the barrels, can I reuse the original rings and before replacing the barrels re-orientate the ring gaps to what they should be at 120deg intervals (but not directly above the gudgeon pins) and with the gaps of the three piece oil rings spaced at 20mm apart? I really don’t want to fit new rings as that will mean a hone and these rings are impossible to get!
Any advice or thoughts welcome
When I removed the barrels during the strip-down I made sure I didn’t disturb the rings or pistons. Once the barrel was off I took notes of where each piston ring gap was in relation to the piston. I was a bit surprised to see nearly all the ring gaps were very close to each other and in one case, the gap for the top and second ring were virtually on top of each other!
The engine has 380 genuine miles from new and has never been apart, I can only assume this is how the piston rings were installed at the factory unless the rings move in service although I’ve never seen this happen before.
So, the question is and bearing in mind there are still feint honing marks on the barrels, can I reuse the original rings and before replacing the barrels re-orientate the ring gaps to what they should be at 120deg intervals (but not directly above the gudgeon pins) and with the gaps of the three piece oil rings spaced at 20mm apart? I really don’t want to fit new rings as that will mean a hone and these rings are impossible to get!
Any advice or thoughts welcome