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Discussion Starter #1
I finally got a set of snap gauges, small hole gauges, and a 2-3" micrometer. I feel like an idiot for not getting those tools sooner, but no use regretting what's already happened. I'm starting to learn the importance of the saying "do it right or do it twice."
Yesterday, I measured my valve guides and they are in spec, so it looks like I don't have to replace the guides (even though I have a new set that I bought months ago), but I'm popping new valves in anyways cos I have a new set and have to replace my bent right intake anyways.

This morning I measured the pistons, and had a few questions about how I should be doing it. I was measuring closer to the bottom (skirt?), but do I need to measure all the way up the piston to get an accurate size? My right piston was 2.5186", which is within the standard value, and the left was 2.5148" which is just under the service limit. I'm hoping I measured the second piston wrong (I had to leave my studio early cos my girlfriend wanted me hangout for Sunday), but I wouldn't be surprised if its worn- it looks and feels older than the other piston. Also when I put the engine together lasttime and tested compression, I was getting about 90psi on the left cylinder (with my POS pepboys compression tester), so it's probably worn. The right cylinder had no compression cos my right intake valve was bent.
I didn't get the chance to measure my cylinders today, so I guess I'll get to that tomorrow along with the piston rings and remeasuring the pistons (thinking about marking the cardinal directions on the top so I line up my micrometer anvil/spindle properly).

To sum up my questions:
Is there a certain distance from the skirt that I should measure to get the most accurate reading?
If one piston is worn, can I replace just that one to match the other? If I have to replace the worn piston, does that throw off the other?
How do I know if I need to bore or rehone the cylinders? Is it just determined on the measurement?
The PO said he had the cylinders rehoned and replaced the pistonrings with new oversize rings before I bought the bike off him, and didn't have much riding time on it after cos the kickstarter jammed on him.

Also is there anything I should be observant of that I wouldn't find in my service manual/isn't common knowledge?
The bike is a '72 cl350, if that information is important.
 

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Pistons aren't round, they are slightly oval. Measure the skirt, at 90° to the wrist pin, near the bottom. The ring groove area is typically a little smaller in diameter than the skirt(and it's round).
 
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