Sparks not sparking Correctly :-(

Posted by Gena on Apr 16, 2013; 7:30am
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/Sparks-not-sparking-Correctly-tp4039477.html

Hi Guys,

I am new to the site so please bare with me. First off all I want to thank you for the amazing site, it has helped a lot with my very own project. My father passed down a 1981 CB750c that belonged to his father, so it means a lot to get it fixed properly.

When I got the bike, it has been on the road for close to 2 years, so I started with the basics. Carb and engine service. Now all is good and it goes well except for the past weekend when something went wrong.

Fist cylinder 1 & 4 did not fire and I thougt the coil was shot as they are both lnked to the same coil. Swapped the coils around and cylinder 1 going now but 3 & 4 was not firing. After a few hours trying to figure it out I got to the following conclusion and here is where I need your help please.

As soon as I remove the cap of the sparkplug, the plug gets life and the cylinder runs. When I place the cap back, it is dead. This applies to Cylinder 3 & 4. As soon as all four caps are on there respective plugs only 2 cylinders are running. I have wrapped my brain around what could possibly be wrong but to no avail.

Please can you guys help me with this one.