Cracking and banging of of exhaust

[buguy]

But your still using the black box right?

[advinnie]

Yes mate

[GARRICK.CLARK]

Adam, I had one of those petronix 3 in my dizzy. Pop bang etc. Yes it was f****d. Fitted points back in it and all is good again.

[advinnie]

I’ve finally found the dam problem. The CB performance black box’s takes its signal from when the points open and it need that signal 70 degrees BTDC. So you wind the engine to 70 BTDC and then rotate the distributor body so the notch in the distributor lines up with the rotor arm, and it’s at this point the points open ( distributor locked)
But that now means that if I want my idle timing at 10 degrees BTDC the crank has to rotate 60 degrees and the distributor has to move 30 degrees passed the contacts in the distributor cap. So the way I’ve sorted it was to advance the point plate by 22 degrees so the black box ignition system got its signal earlier and now it fires when the rotor arm points straight at the distributor cap contacts. If I was doing this set up again from the start and knowing exactly how the ignition box works I would of advanced the distributor shaft first by 22 degrees and then locked it out. I really would of thought CB performance would of know about this little issues cause the more I read on different forums the more people I’m coming across with the same mos fire problem I had.
I will post two photos in a minute that I’m hoping will explain better what I mean.

[advinnie]

in the first photo the ignition advance is set to 20 degrees advance and the rotor points straight at the contacts so at 10 degrees advance it’s only going to be 5 degrees passed the notch not 30 degrees like it is in the second photo witch is how CB performance tell you to set it up.

In the second photo the distributor is at my idle timing of 10 degrees BTDC notice where the rotor arm is when compared to the notch in the distributor body witch is where the number 1 lead contact is it’s 30 degrees passed the contact
I hope this all makes sense?