And it continues…it’s been a while so let me start by thanking you for helping me. After reading thru my previous msgs you showed patience and knowledgeable guidance. Thank you.

So after talking to Honda this block did not leave their company with this piston. Looks like it’s had problems and that doesn’t bother me that much because when I got the unit it ran for 25-30 hours flawlessly and I was the reason it **** the bed.

Here’s where I need your advice. I have assembled this unit several times with the correct rings for this piston and my issue is this;

Every YT video I’ve seen shows the unit rotating very smooth by hand throughout the build. My unit seems to have a spot in the cycle where it’s sounds like some thing is grinding and it becomes hard to turn the shaft by hand.

- is it possible I have cracked the cylinder by sending a non-combustible liquid (h2o) thru the combustion chamber at rpm?
-is it possible that the bearing in side a block for the balance gear has a rough, rust or die bad spot in it?
-The piston does not feel damaged and everything fits snug while being assembled and I don’t see any cracks on the inside of the cylinder but I do see some hairline cracks on the outside of the cylinder head. I thought these might be normal.

No problem Josh...
 
It should spin evenly, (rings will cause some drag of course). 
 
I gather you used at least engine oil on all re-installed moving parts...
 
I'd try to narrow down when the issue arises..
 
IE, check just the crank for easily spinning with the cover on, should be smooth.
Then, install the piston and rod, check again, cover on.
 
If water did get in the cylinder when running, or pulled hard, it's possible to bend the connecting rod.
Check that really closely.  Perhaps remove from the piston and put on a flat surface.(Pay attention to rod to piston orientation).
 
Valves, push them down, one at a time, make sure their not hanging up, closing fully..
 
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Also, that engine is air cooled and water from the pump can only enter the engine thru the carb, not the block...
 
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OK, thank you for that. I did as you said, and everything turns perfectly smooth until the piston is installed. Also, I’m noticing some cylinder wall scraping on top and bottom of cylinder. Piston and rod seam to be mated well so I’m going to check the rod for flatness next. Will a granite countertop work or do I need an actual Measuring deck

Did the cylinder cleanup after honing?  If it's scraped bad enough, of course the piston will have extra friction, if not locking up.
 
Are the piston skirts smooth (and the rest of the pistons)?
 
Will the pistons, NOT bolted to the crank, lubed, move up and down somewhat easily/steady by them selves (push up and down by hand)?
 
Re the rod, I'd take it off the piston (if not visibly bent) and just lay it on a flat surface. Check and make sure both the small end and large end "space" is even when the rod is flipped over and re-checked. 
 
Re any bearings inside. If roller bearings are involved, you should be able to rotate them with you finger. They should be smooth, no slop (sideways or up and down).  A super close inspection of the cylinders should show if there's any cracks..
 
.Scott
 
Can you post some pic's? 

Also, the wrist pin. Does the piston rotate on the rod end easily?

Hey ol friend, so I know what was causing engine to im m im scrape when turning it by hand. Connecting rod is bent. The piston is discontinued so should I buy the regular size piston and connecting rod since it didn’t damage cylinder wall?

A new piston wouldn't hurt(with rings and a good hone).  However, if the piston appears ok and goes up and down in the cylinder (rod disconnected) by hand, it'd probably be alright.  Check very closely around the wrist pin area as well.
 
Rod of course would need replacement.  With that said, something bent the rod, most likely a liquid in the cylinder. Either over filled with oil or more likely, excess fuel leaked from the carb and ran into the combustion chamber.  THAT, needs to be checked..
 
You can hook up the carb to the tank(un-bolted from the engine), fill the tank and just watch for leakage..
 
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