troutbum70 857 #1 Posted May 20, 2020 Kohler K301 cylinder bore, I am not able to find any markings on the piston to confirm if stock or over bore maybe because of all the other marks. So I do not have an actual bore gauge, I did check the top of the bore with my digital dial caliper and got 3.666 so appears to be standard bore. The bore is very clean and shinny with no marks of any kind. Would staying stock make good sense or should it be slightly over bored? I am thinking stay stock if I were do a complete rebuild. Intake valve guide appears to be tight, exhaust has some play. Do these require a machine shop for replacement? And is the a place to acquire a complete rebuild kit of good quality? Share this post Link to post Share on other sites
kasey54 305 #2 Posted May 20, 2020 Good morning. I just looked at engine specs for a k 301 and the bore should be 3.38 inches. .030 over would be 3.368. A k321 would be 3.50 standard bore, Both have a 3.25 stroke. I'd want to verify it's a k301. If it is , then you are .030 over. Share this post Link to post Share on other sites
kasey54 305 #3 Posted May 20, 2020 I'm thinking your reading was 3.366 , not 3.666 Share this post Link to post Share on other sites
squonk 42,572 #4 Posted May 20, 2020 I would measure the bore below ring travel area and then again 3/4 the way up. 3.66" is too big for a 301.. Kohler manual states 3.375 for a new engine. Max out of round .003. A .030 over bore puts it at 3.405" Any Kohler I have come across that had any kind of runtime on it had an out of round cylinder. Even with a perfect looking bore.If it is indeed 3.66" take it to a machine shop and have it checked for being egg shaped. Share this post Link to post Share on other sites
kasey54 305 #5 Posted May 20, 2020 Yes, my math was bad. Model: ................................................................................... K241 ................. K301 ................ K321 ................... K341 Bore: ................................................. inches (millimeters) ... 3.25 (82.6) ...... .3.38 (85.7) ....... 3.50 (88.9). ........ .3.75 (95.3) Share this post Link to post Share on other sites
stevasaurus 23,072 #6 Posted May 20, 2020 I'm thinking, with no marks, it is a standard bore. Still requires the correct measuring of the bore. Share this post Link to post Share on other sites
squonk 42,572 #7 Posted May 20, 2020 1 hour ago, troutbum63 said: Kohler K301 cylinder bore, I am not able to find any markings on the piston to confirm if stock or over bore maybe because of all the other marks. So I do not have an actual bore gauge, I did check the top of the bore with my digital dial caliper and got 3.666 so appears to be standard bore. The bore is very clean and shinny with no marks of any kind. Would staying stock make good sense or should it be slightly over bored? I am thinking stay stock if I were do a complete rebuild. Intake valve guide appears to be tight, exhaust has some play. Do these require a machine shop for replacement? And is the a place to acquire a complete rebuild kit of good quality? I see erosion on top of the piston near the exhaust valve. Be sure to replace it Share this post Link to post Share on other sites
troutbum70 857 #8 Posted May 20, 2020 Yep typo on my part, should proof read more often. At the top of bore is 3.3675, so as I had posted the bore is stock. And did see a small amount of putting on exhaust side of piston. I will pickup a bore gauge and determine bore quality, before moving forward. Share this post Link to post Share on other sites
squonk 42,572 #9 Posted May 20, 2020 You will need a !micrometer along with the bore gauge. Share this post Link to post Share on other sites
troutbum70 857 #11 Posted May 21, 2020 Yep will need to get a larger one, the one I have only measures to 3 inches. Tnx Share this post Link to post Share on other sites
