Any way to tell the bore size prior to teardown?

[EternalArianne]

I was looking at rebuilding the K241 in the my 102 and I'm pretty sure it has never been rebuilt before, but I'm not 100% positive. Is there any way to know if it's been rebored prior to tearing it apart? Or is it uncommon to find ones that have been rebored? I'd hate to buy the "standard size" kit and end up needing a bigger piston. Thanks

[Dirty Steve]

Either take it to professionnal rebuild shop for assistance or obtain a cylinder bore gauge. I have never used one of those gauges and no clue if I could do it accurately. But Columbus took a chance... Good luck!

https://www.amazon.com/cylinder-bore...der+bore+gauge

[EternalArianne]

I have access to a the measuring device, I just wanted to know if there is a way to tell before tearing it apart so I can order the rebuild kit. I guess I may hafta tear it apart to check?

[green407]

Take the cylinder head off and clean the top of the piston, it may be marked.

The piston may be marked "STD" for standard size, or "010" for 0.01 oversized, up to "030" for 0.03" over sized.

[EternalArianne]

My hope is that it was never rebuilt and the cylinder is still in good shape and not overworn or oblong. I guess I won't know until I get in there

[finsruskw]

Pull the head and check, it will only cost you a gasket that way and you will know.
Is it using an excessive amount of oil?
Just what has led you to thinking it needs an overhaul?

Never purchase overhaul parts in advance of a proper bore and crank journal check to determine just what you need in the order of parts.
If you want your big thumper 16 horse to live a long life.......
Do it right and do it once.

[batrider]

My 321 Kohler had a nice shiny film of oil on top of the piston. As soon as the head came off I knew what I was in for.
I have used various bore measuring tools but the best thing to do is have the intended machinist do the measuring. They know a lot more than we do. And whatever you measure will just need to be redone by the machinist.
Russ

[EternalArianne]

Originally Posted by finsruskw

Pull the head and check, it will only cost you a gasket that way and you will know.
Is it using an excessive amount of oil?
Just what has led you to thinking it needs an overhaul

It smokes a bit, especially when throttling up. I suspect it needs valve seals. And it has this terrible rattle sound so I think it has either piston slap or some other kind of wear internally.

[ol'George]

The piston /bore are prolly worn, egg shaped and tapered.
And the crank shaft also needs turned undersize and a new undersize rod.
there are no "valve stem seals"
Quit agonizing about it and take it apart, and send it to the machine shop.
Or put in ear plugs and think pleasant thoughts till it puts a window in the block creating a boat anchor.
They will tell you what it needs then order the parts from the guy on ebay,
Bakt4kids, everything comes in a kit for around $160
Most everyone has good things to say about his parts.
Good luck!

[finsruskw]

He also has new valve guides available as well. Your shop will tell you if you need them. They can install them as part of their operation.
New valves ate part of the O/H kit, the guides are an option and not that expensive.

Good luck and keep us posted!