Who has a stock 2pg piston laying around?

[Morgan44]

I need a measurement of the opening on the side of the piston. Anyone have one around? Old or new doesn't matter as long as it's for the 2pg.

[1989Marathon]

Are you talking about the size of the window on the intake side of the piston?

[Morgan44]

Thats exactly what i need. Don't ask why, long story. Hopefully somebody chimes in before I tear mine apart to find out.

[TheGDFP]

I think I see what you were seeking out, and why. Silly that it doesn't open both ends at once on the rear port, maybe? A year behind, but I'll try to catch up :)




Phazer Wiseco, lower deck, and the window can be cut closer to the top to cool the crown better as well as schedule ports better?

[Morgan44]

Holy cow, I can't believe that's been a year. We were trying to figure out why it wouldn't move enough volume, and thought about trying a 3pg poston. I think it's the jug ports. It's been a year, I'm trying to remember all the details.

[TheGDFP]

I'd noticed that the hole in the piston is too low. 3pg slug would block more of the too-small hole. I'll cut a Phazer one like my CR500 but square it off.

[1989Marathon]

Why not just get a 3pg jug and piston. It has much better flow characteristics.

[TheGDFP]

Originally Posted by 1989Marathon

Why not just get a 3pg jug and piston. It has much better flow characteristics.

Easier for me to cut a hole in the piston than to re-engineer the starter bracket

The 2 and 3 rear transfer/boost ports are the same at their exits. The difference is only that the un-modded 2 piston blocks some of the hole on the bottom of the tunnel. The 3 has more access, but a more convoluted route so I'm doubting the net flow is better. Stock, the added reed/intake area seems the biggest/only advantage to the 3, and Morgan and I have come up with a few fixes for that.

[1989Marathon]

I would think that the advantage of the 3pg jug is that the intake is in the jug and not the case like the 2pg. If you look at the intake tract of the 2pg, it leads right into the crank counterweights and the rod. It seems much more restrictive than the 3pg.

[TheGDFP]

Almost all modern high-output 2 strokes are case-reed, and these have a fairly porkchopped crank so there isn't that much blockage.