as I mentioned earlier ... THE FIRST STEP IS DETERMINING THE SIZE OF YOUR EXISTING CYLINDERS ... in other words how "worn" are they? This must be measured ( a bore gauge ) . because they are stock doesn't mean they have not worn oversize.

 

You want a specific piston to cyl wall clearance. The only way to be guaranteed to accomplish that is to acquire pistons first, measure them (they vary slightly) and then bore/hone the cylinder to a size that will achieve that

If you get STD pistons that are "Small" for your STD bore that may be "Big" ...not good. Along with the condition of your existing bore (eg. Taper, out-of-round)

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"Dial Bore Comparator" (aka dial bore gauge) because your actually comparing two dimensions... The dimension of the piston vs. the bore

You first measure the piston and then set the gauge to "0" using that dimension. When guage is inserted in the bore you see the difference at any place in the bore ("Taper" is also checked this way)

Also turned 90° to check "out-of-round"


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OP ... respectfully you need to step away from the scooter and talk to someone locally who can help you.

 

He's OK...The Ham Fist comes out occasionally, but it usually works out

 

so take them and have them measured first before throwing the baby out with the bath water

 

You can have them measured to get a size and the condition, but it won't help you unless the bore is good condition and then you have access to lot of pistons (possibly a lot) that you pick from for proper clearances.

You can measure with your calipers to get the nominal size

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Here's another angle...find another set of cylinders, buy appropriately oversize pistons/rings and have them "fitted".

Sell your 15-16k take-offs to someone with a 883 or worn-out 1200

 

thinking out loud here, looks like a job for a hammer blems set.

blem kit (cylinder, pistons, etc..) is 499 or maybe hammer is feeling generous... *WINK WINK*

vs

new pistons ~250.... new cylinders ? ~300? dunno shop to bring it all together ~75-90/hr


not pretty.

i can cancel the order on the pistons, again lol. i havent pulled the cylinders yet so everything is still in place. i could scratch the piston deal altogether but, it seems like it would be a waste of the new se cnc ported heads.

man up moment. plenty to ponder. i'm in no rush.