If you have noticed strange line-like markings or evidence of electrical arcing on you head gaskets, pistons or bearings, chances are you may have a magneto grounding problem. Visualizing the secondary current flow, it would start at the generator, pass through the points box to the coil, through the cap, rotor, wires and end up at the spark plugs in the heads. It should then complete the path back to coil (-), which is ground. However, if the path between the cylinder heads and coil (-) is not optimized, the current will generally find or make it's own path to complete the circuit. Often it is assumed that motor mounts and head studs will provide adequate ground when they really don't. To address this issue, we now suggest that both heads be grounded to a single point via a braided ground. This point should be the same as that shared by both coil (-) leads.
Note: If a Timing Retard PN 8168 is used, make sure that the points box case or cases are grounded to the retard box case. If this is not done, you may experience poor engine performance and "noisy" data traces on the RacePak display.
Click Image To View A Wiring Digram