Re: Jetting Problems

Posted by 79-CB750F Owner on Apr 28, 2011; 3:33pm
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/Jetting-Problems-tp458345p2875140.html

I had numerous problems with my carbs when I first bought the bike because of rust and paint in the gas tank.  I learned a lot about those carbs overhauling them and cleaning them numerous times.  I believe that assuming your throttle cable linkage and return spring are all functioning and the bike takes time to wind down the rpm's then it is very likely to be the vacuum piston, chamber, needle etc.  Those must all be spotlessly clean in order for the piston to travel up and down as it controls your acceleration and deceleration.  I suggest using using a carb cleaner, air compressor and clean lint free rags to clean your carbs...especially the vacuum piston side.  Make sure you are using good filter(s) out of the tank to the carbs. I actually have 2 in line, one being a paper filter.  I also took off the vacuum hoses that control the throttle response and blocked the one vacuum port.  You will fine that most remove all that crap and the carbs run better.  

Those cheap pods came with my bike and everyone told me to get rid of them and get an airbox.  I actually bought an airbox but haven't put it on yet due to the fact the bike (1979-CB750F) is running great.  The former owner put in 105 jets when he did the pods, although I'm not convinced that was necessary.  I used the K&N cleaner/oil to clean the pod filters.  After getting the gas tank clean, good filters in line, and the carbs spotless clean and functioning smoothly the bike ran great.  Of course I also did all the valves set to .005,  replaced the rubber boots holding the carbs on. and did carb synchronization with the vacuum guages.  I've had all the problems discussed in this thread...and have fixed them all.