Poor K181 couldn't take it-
 

All that nice compression, flattened cylinder head, new gaskets, smooth sealing valves, clean carb and fresh oil was just too much for it.

Got it all back together, sounded great, and a couple minutes in a loud BANG. Cylinder not moving but valves are so I'm guessing a broken connecting rod.

Should have it back on the bench soon and will get some pics of what I find.
:bash2:

I learned that lesson the hard way too. Now anytime I open up a crankcase, it gets a new connecting rod. It is cheaper than a second tear down.

Yep - now I know. This will be my first time in that part of the engine.

I read an article that explained the "stress fatigue" that the aluminum rods develop over a period time, that heat and lack of maintenance can cause. It all made sense to me. Since, I have seen numerous posts on several different citing the same situation that you & I have experienced.

Lesson learn.........New Connecting Rod(s).

:IH Trusted Hand:

Total carnage-

looks like the governor bit it too, wonder if that happened first. There are small chunks broken off the bottom of the cylinder bore so I assume this is a goner.

http://i1375.photobucket.com/albums/...pskkxk009h.jpg

http://i1375.photobucket.com/albums/...psjly6sozh.jpg

http://i1375.photobucket.com/albums/...psjejiqzpg.jpg

Sorry man, hope you can find a replacement

Thanks Terry-

I enjoyed working on this so not the end of the world.

Will any motor out of a narrow frame work in a 70 frame? I know carbs, exhaust and gas tanks may differ but wonder about a 10 or 12 hp if I can find one.

thanks,
Tim

even a wide frame engines will work . 14 hp and 16 hp will not work

10s and 12s are a direct bolt in if they come from a cub. Sorry to hear about the explosion I've had it happen as well no good

I'd say the rod sized on the crank and that started the problem.
Lets see some pictures of the block spigot, many times a chunk out of them causes no problem.
Clean up the crank,prolly .010 under, do what is necessary to the bore, check/do the valves and you are back in business, and you will have a "new engine" rather than some turpentine overhaul used one from evil pray or ??
----just my $.02.:BlahBlah: