View Full Version : 4-2 4-2-1 or 4-1 exhaust system for mid to top end power 84 cb650

08-28-2016, 1:41 PM
the motor I've got used to power a nighthawk.. now its in something else (not quite chop cult related) anywho im looking for the best mid to top end power. need to shed some weight also, so I'm leaning towards the 4-1 or 4-2-1 setup. but which design is better for mid / top end? and what would be an ideal pipe diameter?

08-28-2016, 3:48 PM
Generally 4-1 will work better for scavenging exhaust and give you better power in the mid to top area. Great resource for figuring out the best dimensions, etc is here http://www.wallaceracing.com/header_length.php

08-29-2016, 10:36 AM
that would be handy, but i can't find valve / cam specs anywhere any suggestions? i know those motors had 50 and 60hp cams and i plan to run the 60 cams if it doesn't have them already... stuck recuperating from surgery, so all i can do at the moment is research...