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moonpie 4 – 4 race exhaust
Sounds like you've got a reasonable base setting with the jetting so shouldn't be giving you anything out of the ordinary. Spitting back through carbs has to have some pre-conditons. Inlet valve has to be open to allow the combustion to go back out that route, this is usually achieved by ignition being too advanced but you've got yours ok at tickover so it shouldn't be a concern. But as far as I can see, that firing of all cylinders will give this condition. If you look at no1 cylinder coming up to compression it will fire something like 10 degrees before top with both valves closed, giving the power stroke. At exactly the same point, no3 will be on its intake stroke with piston 10degree before bottom and just the inlet valve open. This should fire that mixture straight back out the intake IF it ignites, giving you spitting.What Boyer won't disclose is the strategy around this, is there a lock out for all plugs firing at the same time? If so is it based on a rev floor limit? Or could it be set on time basis ie if you switch ignition on will it give a time base of just firing plugs conventionally (say 30 secs) after which it expects to see the engine above a certain rpm (perhaps 700 rpm) and return to multiple firing? These are some of the things you'd find in even fairly old ecu controlled systems, so perfectly possible. You could try turning on and immediately starting it to see if it spits at you, or pose the question to themThat makes sense K2 - K6. I bought the Boyer system based on having done trouble free miles over about 40k miles in the 70s - TBH, I wish I'd gone for another make. I'll put the question to them Thanks
Sounds like you've got a reasonable base setting with the jetting so shouldn't be giving you anything out of the ordinary. Spitting back through carbs has to have some pre-conditons. Inlet valve has to be open to allow the combustion to go back out that route, this is usually achieved by ignition being too advanced but you've got yours ok at tickover so it shouldn't be a concern. But as far as I can see, that firing of all cylinders will give this condition. If you look at no1 cylinder coming up to compression it will fire something like 10 degrees before top with both valves closed, giving the power stroke. At exactly the same point, no3 will be on its intake stroke with piston 10degree before bottom and just the inlet valve open. This should fire that mixture straight back out the intake IF it ignites, giving you spitting.Have emailed Boyer based on your point - thanks again K2 - K6What Boyer won't disclose is the strategy around this, is there a lock out for all plugs firing at the same time? If so is it based on a rev floor limit? Or could it be set on time basis ie if you switch ignition on will it give a time base of just firing plugs conventionally (say 30 secs) after which it expects to see the engine above a certain rpm (perhaps 700 rpm) and return to multiple firing? These are some of the things you'd find in even fairly old ecu controlled systems, so perfectly possible. You could try turning on and immediately starting it to see if it spits at you, or pose the question to them