How much is too much? After honing my jug I got around .005 piston to wall clearance, I`m sure this is too much. But I am asking only to find what the limit is. I know on automotive it`s suggested not to go over .006, but we`ve went all the way up to .008 and got away with it. I know on these engines it`s different.
I checked it with the piston in the middle of the bore and a .005 feeler gauge.
A .006 would go only if I forced it. The piston without rings does seem a little on the loose side. I`m thinking yeah I could build and run it but it might run 3 months before it`s smoking again. Thanks.

 

Doesnt matter what any book says because you must go by the piston. Forged pistons such as Wiseco for example use a greater clearance than a factory style cast piston because forged pistons "grow" as the engine gets hot. Your piston should have came with a small leaflet telling you the clearance recommended and the clearance recommended on your ring gap....which is also different from onw piston to the other based on the same reason.

 

Thanks Knows. Unfortunately, The piston came off ebay as NOS (new old stock)
And didn`t have a leaflet with it, it`s a real Honda piston, it has Honda on the side of it and 25, So the book was all I had to go by. I did find another jug and honed it to .0025 clearence, but I will ask the guys at the honda shop what the clearence should be when I go for the cam bushing and washer. My nephew just reassembled his 200x and he said it ran great for a little while then went to busting at upper RPM`s. He noticed the head gasket was blown, I asked him when he used the different head did he have the head and jug milled to assure they were flat? he said no, I said no wonder. I really appreciate all your help. And I`ll keep you posted on how it`s all coming along, with my back being screwed, it`s slow, but I`m getting there and doing it right, cause I don`t wanna have to go back and do it all again. Thanks again Knows.