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When I check my piston to wall clearance I flip the cylinder up-side-down and install the piston as it normally would be. I then force the piston all the way to one side of the cylinder and insert a feeler gauge between the cylinder wall and piston skirt. I'm on 64.75mm bore and my piston to wall clearance is around .001 to .002 I have read that my clearance is to tight and I have also read that I'm just right. What do you guys think should I get my cylinders honed out so I have around .003 to .004 or stay where I am?

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When I check my piston to wall clearance I flip the cylinder up-side-down and install the piston as it normally would be. I then force the piston all the way to one side of the cylinder and insert a feeler gauge between the cylinder wall and piston skirt. I'm on 64.75mm bore and my piston to wall clearance is around .001 to .002 I have read that my clearance is to tight and I have also read that I'm just right. What do you guys think should I get my cylinders honed out so I have around .003 to .004 or stay where I am?

That is a really inaccurate way of doing it. You should be using a bore gauge or inside micrometer to measure the cylinder, and you should be using an outside micrometer to measure the piston. If you are using Wiseco pistons you also need to know the correct place to measure them as they are oval shaped when they are cold and when they come up to temperature, they become round. This is because they have a steel strut in them that controls expansion.

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Read >HERE< , first paragraph explains how to measure clearance. You'll need one of >THESE< and some of >THESE<.

A dial caliper is not nearly as accurate as an outside micrometer, ther is to much flex in the mechanism and jaws that do the measuring. A dial caliper is great for quick and easy measurements to get an idea of the general size of things.

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A dial caliper is not nearly as accurate as an outside micrometer, ther is to much flex in the mechanism and jaws that do the measuring. A dial caliper is great for quick and easy measurements to get an idea of the general size of things.

 

Yep probably just as accurate as using a feeler gauge when checking bore's. It is better than a ruler though.

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I'm going to go ahead and say that the .001" feeler may be close to accurate in this application. .004 or so and there will be a noticeable amount of loss of feel due to the curve of the bore.

If you truly believe it is .001 and the piston spec is .004, I'd hone it out to .004". Better loose than tight.

 

And if you have any doubts get a machine shop to check it.

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