I just bought a Honda 400 ex with the 440 big bore and when I was riding it started cutting out when you would get into the higher speeds. Someone told me the jetting could be off. How do you find out what the proper jetting would be?

 

try this www.exriders.com

 

Jetting is as much art as it is science, and it is done by making changes (start out to rich and work down) and then riding the bike to see what the change did. If you want to get riding quickly, it is best to have it done by an experienced professional. If you want to learn jetting, it will take a lot of trial and error experience!

Some carb theory: http://www.dansmc.com/carbs2.htm


A stumble at 3/4+ throtle could meant the main jet is the wrong size, and/or the needle is in the wrong height or the needle is the wrong shape.

 

http://www.highlifter.com/foru...Guide/m_1872049/tm.htm