I have a 1974 cb750 with an 836 kit, stock cams, valves adjusted correctly. Dyna s ignition and two high out put coils and good wires.timing is set per the book. main jets have been drilled out to wire sizes larger then stock which is what the guy who do the cylinder bore told me to do.
My problem is that i get pinging ( pre ignition) in the mid range.Is there something i have to do like advance the timing? i have tried this and it didnt seem to help. I'm thinking of raising the needles. Will that do it? I know there are lots of these set ups running good out there and just what some direction . I really want to get this great looking bike runnin right this season .
Yhanks
