That STINKS! I've been in that situation before and it came back to haunt me. I now make it a habit to tear things down and check them out good when I don't know their past. For example when I bought my DC Case farm tractor I picked it up on a windy 14 degree day. It started off to load like a dream and when we got it home a slight pull of the choke and it was off and running. I gave it a few laps around the field and thought heck this thing is good to go engine wise. It ran super quiet and didn't miss or carry on or anything. Woohoo, life is good.
Fast forward to tear down time. I pulled the head only because I was wanted to put on a new head gasket so I had no leaks after paint. Much to my surprise when I pulled it I found 2 horribly burnt exhaust valves on #1 and #2 cylinder's. After removing them from the head all the exhaust seats were burned bad as well. I checked the bores and the piston's all had at least a 1/16" gap around them. Time for further tear down and pretty extensive surgery. I learned that the cam thrust washer which was made of fiber from the factory often needs replaced. When I pulled the cam the washer was non existent and the new one made by some knowledgeable Case guru's is brass so it will last forever now. Lot's of other things along the tear down that were questionable as well So needless to say it needed extensive repair.
After that I chance nothing and make sure all is well first off. Not to say you did it wrong, just my experience that it seems to come back to bite a guy when not investigated. By the way, I'm jealous. A 169 is on my list to own one day. I had a 1450 I wish I would have never sold years ago. Maybe a 169 can replace it someday.
Here's a pic of the one valve and the better of the 4 exhaust seats. It's amazing it ran the way it did.
Edited by IHCubGuy, February 25, 2018 - 11:42 AM.