Everything2Stroke Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
189 Posts
not sure what engine your refering to but its unlikely youll be able to cut any in because of the inlet design. but besides that i dont think it would do any good. usually on the case reed design, the reed block dumps right into the crankcase area with little obstruction. cylinder reed typically has dividers and such partially blocking the inlet which reduces its area so boyesen ports can be helpful. i think also the boyesen can offer some assistance for the rear boost port up the back of the cylinder on a cylinder reed design. case reed has a stand alone boost port that needs no assistance and there should be little or no obstruction through the inlet area. so i would say even if you could cut in some extra ports they wouldnt do any good but then again ive never tried it
 

·
Vendor
Joined
·
1,500 Posts
You probably don’t have room but a good even array of boost / transfer ports is good. If you already have a rear type of porting, a couple of holes in the rear of the piston may be helpful. Holes in the piston aid in lubrication & cylinder cooling.


A DH type of boost port jig has been working for me for many years. Most of you folks are too young to know about Dale Herbrandson Reed Valves.




400 CZ DH reed


Reed conversion with rear boost ports.


Boost porting in CR250 cylinder



Some of us Old Farts have been around since reed valves started to show up in the early 70’s
:Smoke:
 

·
2 stroke thinker
Joined
·
2,062 Posts
Piston port was the heads up technology til they designed the reed valve setup.
Still to this day... The Piston port is being refined by the advanced shop to the "back yard guy".
Adding a nice pipe,carb,etc... they performed rather well for what they could do performance wise.
Good Luck and if anyone has any tips and tricks, Let us know as this is a 2 stroke information highway !!
 

·
Registered
Joined
·
45 Posts
Discussion Starter #5
I refering to a cr125 cylinder, 99 model year. I didn't know if it would help in any way but I cut them in. I have to do more blending but I figured I would give it a shot.
 
1 - 7 of 7 Posts
Top