Re: 79 cb750 dohc only running on cylinder 3&4

Posted by Parzival on Aug 20, 2018; 5:32pm
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/79-cb750-dohc-only-running-on-cylinder-3-4-tp4063709p4063712.html

Finally had a chance to check all my bases today. The plugs were terribly fouled/bairly could get a spark. So with new plugs I found that 1&4 had a pretty week spark compared to 3&4. Installed and cranked up running on two occasionally 3 cylinders. Pulled the plugs after about 2 minutes at idle for a look. 1 was lightly covered in black soot, 2&3 heavily covered and very black, number 4 clean as a whistle. After this I ran a compression test #1&2 140psi, #3 135psi, and #4 0psi.
I double checked that zero psi reading a few times to make sure it was correct (which it was) before dumping some oil in the cylinder which brought it up to 30psi. So that's where I'm at with it today. Again I appreciate the help