Mr Magoo 226 #1 Posted October 26, 2020 (edited) I dug into the K181 on my 856 that has been sitting for at least 20 years. Taking off the air cleaner housing I saw quite a bit of oil pooled in the cover and in the throat of the carb. When turning the engine over I am getting a pretty audible click. It is definitely coming from the exhaust side. I removed the breather cover and everything looks fine with the springs. Rotating the engine and placing my finger on the exhaust spring I can feel the snapping quite a bit. One thing I find interesting is that it only does it every other revolution. I am assuming has something to do with the tappet. The video pretty clearly has the sound and shows how the valves are behaving during the cycles. You can see the exhaust valve jump when it makes the noise. Here is a link to the video on YouTube. YouTube K181 video MVI_2492.MOV Edited October 26, 2020 by Mr Magoo Added a link for video Share this post Link to post Share on other sites
pfrederi 18,810 #2 Posted October 27, 2020 The ACR makes the exhaust valve open slightly on the compression stroke. 1 Share this post Link to post Share on other sites
The Tuul Crib 7,339 #3 Posted October 27, 2020 Is the valve spring possibly broke? Share this post Link to post Share on other sites
pfrederi 18,810 #4 Posted October 27, 2020 K-181 valves are not adjustable have you checked the valve tappet clearance. per manual it is .017 -.019 cold. If they are too loose it is repair by replacement. To tight you grind a hair off the valve stem. be very careful not to get carried away. i have a nice tick on one of mine as i took off a bit too much. 3 Share this post Link to post Share on other sites
Mr Magoo 226 #5 Posted October 27, 2020 55 minutes ago, pfrederi said: K-181 valves are not adjustable have you checked the valve tappet clearance. per manual it is .017 -.019 cold. If they are too loose it is repair by replacement. To tight you grind a hair off the valve stem. be very careful not to get carried away. i have a nice tick on one of mine as i took off a bit too much. I will check that next. Any idea why it would be happening on every other revolution? Share this post Link to post Share on other sites
ebinmaine 73,663 #6 Posted October 28, 2020 Would that explain one valve? Intake. Compression. Power. Exhaust. Down. Up. Down. Up. Noise. Down. Up. Down. Up. Noise. I'd agree one of the 2 valves is in need of attention as you surmised. 1 Share this post Link to post Share on other sites
pfrederi 18,810 #7 Posted October 28, 2020 Note the spec I gave you is for the exhaust valve only (thought that was the issue,,, Intake is tighter .006 to .008. 1 Share this post Link to post Share on other sites
Mr Magoo 226 #8 Posted October 29, 2020 13 hours ago, pfrederi said: Note the spec I gave you is for the exhaust valve only (thought that was the issue,,, Intake is tighter .006 to .008. So how did you grind your valve stem? Doing the valves is the one thing that is intimidating me from doing a rebuild myself. I have never done a rebuild. Share this post Link to post Share on other sites
pfrederi 18,810 #9 Posted October 29, 2020 I used a grinding wheel but it took too much off to fast. I would see if some one more skilled answered. Do you have a valve spring compressor?? 1 Share this post Link to post Share on other sites
Mr Magoo 226 #10 Posted October 30, 2020 11 hours ago, pfrederi said: I used a grinding wheel but it took too much off to fast. I would see if some one more skilled answered. Do you have a valve spring compressor?? I do not. I will have to pick one up when I get into it. Share this post Link to post Share on other sites
