Well I have been taking a few of these less expensive saws apart and doing some porting, but only widening the ports. Mastermind and a few others have convinced me to get a degree wheel and time one of them. So what I have is a Poulan 260 42cc open transfer clamshell. Here are the numbers as they are right now. I did raise the transfer alittle for the blowdown.
Exhaust opens ATDC 103*
Duration it is open 62*
Transfer open ATDC 123*
Blow down 20*
Intake opens ABDC 106*
Duration it is open 38*
The intake does not seem to be open for a very long duration and I was thinking of lowering the port. There seems to be plenty of time from when the exhaust closes to when the intake opens. Looking for suggestions.
Exhaust opens ATDC 103*
Duration it is open 62*
Transfer open ATDC 123*
Blow down 20*
Intake opens ABDC 106*
Duration it is open 38*
The intake does not seem to be open for a very long duration and I was thinking of lowering the port. There seems to be plenty of time from when the exhaust closes to when the intake opens. Looking for suggestions.
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