Re: G80CS... and the saga continues
Posted: Tue Sep 18, 2018 11:55 am
Right the mag is definitely a comp one and pulling the lever pulls the cam ring upwards retarding the ignition, ie it rotates the ring in the direction of the arrow which moves the start of the cam ramp away from the heel of the points fibre foot. If it leaks from the head when a copper gasket is being used then I'd suggest you also remove the barrel and lap the head to the barrel with grinding paste to ensure both surfaces are a good fit. Thorough clean down to remove the grit and then anneal the copper gasket for re-use. When setting the ignition it's best not to loosen the mag sprocket as the book advises but pop the exhaust cam sprocket off its taper instead.
First pop the exhaust cam sprocket off its taper. So starting with the basics for timing (forgive me if I'm appearing to be patronising) bring the piston to the firing stroke TDC. Insert your rod in the plug hole and mark it at a convenient point. Remove and remark 7/16th or 1/2" higher up the rod insert again and rotate engine backwards in gear. Go back further than the mark on the rod and then slowly bring the motor forward until it reaches your mark that you put higher up the rod. That's your advance timing mark point. Go round to the points side of the mag and rotate till the points heel is just about to open the points ( a mag timing light is really useful for this as it saves using the fag paper method). Once you've established the opening point go back round to the exhaust cam which you loosened. Put a large socket onto the cam sprocket face and gently give it a tap to put the sprocket back onto the taper ensuring that you didn't move either the motor or the mag sprocket. Then lock it up.
First pop the exhaust cam sprocket off its taper. So starting with the basics for timing (forgive me if I'm appearing to be patronising) bring the piston to the firing stroke TDC. Insert your rod in the plug hole and mark it at a convenient point. Remove and remark 7/16th or 1/2" higher up the rod insert again and rotate engine backwards in gear. Go back further than the mark on the rod and then slowly bring the motor forward until it reaches your mark that you put higher up the rod. That's your advance timing mark point. Go round to the points side of the mag and rotate till the points heel is just about to open the points ( a mag timing light is really useful for this as it saves using the fag paper method). Once you've established the opening point go back round to the exhaust cam which you loosened. Put a large socket onto the cam sprocket face and gently give it a tap to put the sprocket back onto the taper ensuring that you didn't move either the motor or the mag sprocket. Then lock it up.