tomtractor 71 #1 Posted April 15, 2014 On my tractor there is a jerry rigged exhaust system. The Kohler k301, 12hp, exhaust outlet starts at 1 and 3/8 inches and is reduced to 1 inch. Do you think there would be a loss in power due to the wrong 1inch pipe? Sorry it is a boring topic. Although modestly interesting? Share this post Link to post Share on other sites
TT-(Moderator) 1,128 #2 Posted April 15, 2014 That sounds like a K-341 if the exhaust port is 1 1/4" (not 1 3/8") and is immediately reduced to 1" How many head bolts ~ 9 or 10? Share this post Link to post Share on other sites
tomtractor 71 #3 Posted April 16, 2014 TT, you are correct the port pipe is 1 3/8th of an inch. But with that said would performance be hindered it it was reduced to 1 inch? Also the motor is without question a K301. Share this post Link to post Share on other sites
Nathanielperz 150 #4 Posted April 16, 2014 I am wondering the same thing Tom. Nate Share this post Link to post Share on other sites
rmaynard 14,909 #5 Posted April 16, 2014 Maybe the confusion is that a 1" galvanized steel pipe has an OD of 1.32" (1-5/16" +/-) Share this post Link to post Share on other sites
tomtractor 71 #6 Posted April 16, 2014 In my application the pipe I am trying to fit a muffler to has an OD of 1 inch. Share this post Link to post Share on other sites
rmaynard 14,909 #7 Posted April 16, 2014 (edited) 3/4" pipe has an OD of 1.05". Sound to me like you have a 1" exhaust outlet being reduce to 3/4". Remember, all nominal pipe sizes are inside measurements. As to the second part of your question, I have always been told that reduction in pipe size can reduce power, not to mention overheat the exhaust valve. Edited April 16, 2014 by rmaynard Share this post Link to post Share on other sites
