I was doing my homework for performing an engine rebuild and came across an article which said that you need to measure the ring end gap at the bottom of the cylinder where there is no wear. My bike's service manual said the same thing ( =measure at the bottom of the cylinder) and I wondered why, because most vids on here measure near the top of the cylinder. Due to wear the top of the cylinder is usually wider than the bottom. If you set the minimum gap near the top of the bore, as the piston goes down during combustion stroke, the piston gap will be smaller (maybe too small) at the bottom of the bore. On the other hand, the stroke length in a motorcycle cylinder isn't that much, so the change in gap (I read 0.003" per inch if the top of the cylinder bore is 0.12" larger due to wear) won't be much.
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Great info! Thanks
Great video, appreciate the information!
I was doing my homework for performing an engine rebuild and came across an article which said that you need to measure the ring end gap at the bottom of the cylinder where there is no wear. My bike's service manual said the same thing ( =measure at the bottom of the cylinder) and I wondered why, because most vids on here measure near the top of the cylinder. Due to wear the top of the cylinder is usually wider than the bottom. If you set the minimum gap near the top of the bore, as the piston goes down during combustion stroke, the piston gap will be smaller (maybe too small) at the bottom of the bore.
On the other hand, the stroke length in a motorcycle cylinder isn't that much, so the change in gap (I read 0.003" per inch if the top of the cylinder bore is 0.12" larger due to wear) won't be much.
Couldn't you use the piston as a tool to push the ring down flush?
Yes. If the dome doesnt hit the ring. Depends on bore size and compression to do so
Can't believe people know enough to change out the piston but not know about ring gap
So fuel type doesn't really matter?
Depends on compression piston