Piston questions 185s with 200 jug.

[79fordblake]

Well after getting my 185s all back together after having new valves and seats cut along with all the timing parts replaced I still have a noise. Found out that it is piston slap. Took the head back off and there is a ton of clearance between the piston and cylinder, you can move it back and forth. It has a 65.50 piston in it right now(with 200 jug).
Will I have any problems with going up to the 66mm 10.25 compression wiseco piston? The cylinder is completely glazed over. It is supposed to have new rings from the previous owner not long ago, which is obviously a lie. But how did there become so much clearance between piston and cylinder? Machine shop didn't know what they were doing?
A 66mm piston will be the last boring of the 200 jug won't it? If so thats ok, when it starts smoking after this round ill just get another 200 jug, they don't cost that much.

[atc500x]

I think there is a 1.25 and 1.5 over (66.25 and 66.5) for the 200 available.Bore it and ride!

[Scootertrash]

Wiseco lists a 66.0,66.50 and a 67.0mm piston for the Honda 200(S) motor:
http://www.wiseco.com/ProductSearch.aspx

Honda cylinder bore to piston clearance spec is : 0.015 to 0.055mm
or 0.0006 to 0.0022 in

If you don't have the ability or tools to check the dimensions a good machine shop would probably do it for free to tell you what you actually have going on as far as piston size and bore size and bore to piston clearance.

[79fordblake]

I have the ability but I don't have the tools. Just from some past experience looking at tolerances from engines in diesel school this thing is for sure way past spec as much as I can move the piston back and forth. It has way over a couple thousandths wear, which you can feel and see I don't see how it doesn't burn oil like crazy, it is burning a little.
I just wish I knew what the previous owner did to make this mess, surely a well known machine shop didn't do this.

[79fordblake]

I have been seriously thinking about going with the 12.1:1 piston. Any reason not to? My idea behind it is after its all said and done and put together the 10.25:1 piston probably does not make 10.25:1 compression and the 12.1:1 is probably making more close to 10.50 or 11. Anybody out there know for sure?

I am running regular gas right now with a 65.50 10.25 piston. I got the numbers off of it and found out it is a older wiseco. Since cylinder is worn that may have something to do with it but it currently doesn't ping at all.
On the other hand if anybody knows if the 12.1 piston makes close to what it is supposed to I may not want it b/c ill have to get 102 octane probably.
Another question I have is as long as I use the correct fuel and have it jetted right will the 12.1 piston last as long as the 10.25?

Just had another idea run through my mind after searching through other posts. Is there a thinner head gasket off of something else that will go on the 200 jug? If i could find a thinner head gasket than the stocker then i would run with the 10.25 piston.

[79fordblake]

Still been doing research but really haven't found the answer. Anybody know if there is a different head gasket I can get to go with the 10.25 piston and make compression a little more higher?

[Sick200x]

I'd stick with the 10.25, buy your piston and take it all to the machine shop to be bored to the proper size. There won't be a world of difference with the 12:1, plus you won't have to worry about the fuel and the jetting should be pretty close. As for a thinner gasket? i don't believe most gasket sets will offer much more for that engine, I did however have a riding buddy of mine who had one cut from some thin copper sheeting, I forget the actual thickness. The gasket never failed, although it was a trailprotrailprotrailprotrailprotrailpro to start, definately needed boots(which you should ride with anyways),eventually while working it pretty hard the motor stopped dead...tore it down to find the rod twisted like a twizzler! maybe due to the high compression but not sure.....