so your saying the exhaust shape should be more rounded due to piston dropn below it. does this help keep the rings from hangin up. but in that same note your saying a squarer port is better than round.
Yes and yes
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. A perfectly square port would give the most flow and therefore performance. However, it must be rounded to prevent snagging the ring. On the exhaust, both rings have to travel past both the roof and floor of the port. On the intake that's not the case so you can go flatter. If flat, the full width of the port is opened immediately. The more rounded it is, the farther the piston has to drop to get the port wide open. It's a balancing act between performance and reliablity on how square you go.
i might widen the transfers alittle more just because its quick and easy. it sounds like id be safe to take alot more out but i fell ive already taken out quite abit, 1/4" wider or so and blended back. that should make a pretty big difrence from stock(whatever that is)
If you've already widened 1/4", I'd probably leave it. Keep in mind that you're not only widening the transfer for increased flow, but also angling them back towards the intake to direct the fresh charge at the rear of the cylinder and help the scavenging process of forcing out the exhaust.
im not sure i understand about what you mean by the bottom of the intake. i thought i didnt want to lower at all. from what i understand on the intake. you want to go wider and stay square as much as possible. is this right
Exhaust flow happens as the piston drops from TDC and opens the top of the port. Therefore, it's the top of the port where most of the flow happens. Raising the exhaust roof increase exhaust duration, but also lowers compression. I don't raise the exhaust unless I have to to get a good port shape.
Intake flow happens as the piston rises from BDC and begins opening the bottom of the intake port. The floor of the port is lowered to increase intake duration, just like you raise the roof of the exhaust to increase duration. I often lower the intake 1*-2*. I also widen the intake just as I do the exhaust.
Brad
your gona hate me but this porting has got me thinkn about the 084. and what could happen there. with bigger cylinder the porting should be easier
Reguardless of what you do with your 084, you
need a 046/460!
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