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what does a ported 2t piston look like

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depends on what the cylinder looks like..............if the piston skirt shrouds the front transfers at btc they trim around the cut out making sure that it doesnt open up to the exhaust port at tdc if the engine is a piston port they might open up the intake cutout to increase intake port timing seriously affecting low speed power for top if the engine is a case reed they might shorten, massage or drill the intake skirt to unshroud the rear transfers making sure they are not risking breaking the skirt from lack of load bearing or catching the inlet

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depends on what the cylinder looks like..............if the piston skirt shrouds the front transfers at btc they trim around the cut out making sure that it doesnt open up to the exhaust port at tdc if the engine is a piston port they might open up the intake cutout to increase intake port timing seriously affecting low speed power for top if the engine is a case reed they might shorten, massage or drill the intake skirt to unshroud the rear transfers making sure they are not risking breaking the skirt from lack of load bearing or catching the inlet

I don't think that's what he meant. I think he was talking about normal 2s vs piston port. Piston port motors have actual ports in the piston. Like the side of the piston skirt will have nice square holes that line up with the intake port. it really depends on the design. Piston port is mostly on motors that came out before case reeds, because the intake couldn't make the hard bends to line up with the crank case. Case reed gave a straight line so it didn't have to pass through the piston.

Piston port

dsc00038.jpg

Normal,

788M05800-500x500.jpg

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The above piston pictures are misleading. There are MANY reedvalve and casereed pistons that have a window on the intake skirt. Check Wiseco's application for Honda CR125 motors 1991-1999. They offer both pistons with and without window. Standard had a window. My 76 RD400 has reedvalve and the twin-window pistons.

Most engine builders port around a stock piston to make replacement simple. In some cases, there can be gains from modifying the piston. On a bridged exhaust port, it is always a good idea to drill the exhaust skirt to supply a fuel/oil charge to the bridge to keep it cooler and well-lubed (always a plus!!).:bonk:

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Not sure what the original question was intending but I understood it to mean a modified piston compared to a stock replacement piston. An old tuning trick was too modify the top of the piston to change port timing and do test runs instead of opening up the cylinder and rendering it useless.(if your calculaqtions are wrong and you mess up a lot cheaper to by a piston than a cylinder)

the 1979 yz it 400 engines are extremely similar with the yz having a large intake cutout compared to the it having windows in the intake skirt. both are reed valve engines.

to the O.P. If I am understanding the question correctly there are four basic 2st engine designs piston port, rotary valve,cylinder reed valve and case reed valve. Each one having numerous port configurations and piston designs, 4 basic ways of porting your engine more low speed,midrange,high speed, and better spread of power.the possibilities are mind boggling on what you can do to a 2 stroke but very limited to what you can do you particular engine for the power you want

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they're indestructible thats why lol

They're close to it. I killed one. took the crank case freezing, running lean for an entire day with a leaking crank seal, and a hot day trying to keep up with two ktms, but it can be done. Pretty freaky too, when the rear wheel locks up at 40

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They're close to it. I killed one. took the crank case freezing, running lean for an entire day with a leaking crank seal, and a hot day trying to keep up with two ktms, but it can be done. Pretty freaky too, when the rear wheel locks up at 40

damn ive tried to kill it but not that hard lol

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First of all a piston ported engine uses the piston skirt to control intake timing. There are no holes in the skirt. On a reed valve (non case reed) the reed controls intake timing through crankcase pressure cycles so in order to fill the case with as much charge as possible the intake skirt has openings to allow more charge entry. The intake port never actually closes because it's not used to control timing on a reed.

Now onto the OP's question. The above photos of the squared holes in the skirt are one way pistons are modified for porting. Some porters use the exhaust side of the crown to extend exhaust port timing as pictured below. I don't recommend it but whatever floats yer boat. Doesn't do anything for the transfer flow/timing only allows more RPM if the pipe will allow it. Doesn't do a lot for top ring heat control either.

vitos_exhaust_port_opening.jpg

piston_top_view.jpg

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