Piston Port vs Reed Valve Intake (2 stroke)

[@billclark5943]

I've studied you work on the internet for over a decade. Never knew you had a youtube channel. I see I have plenty to watch

[@MichaelForrestChnl]

For motorized bicyclists: After I did this video I got a Speed Carb to test against the stock NT carb and I found the NT was best suited for piston port engines, and the Speed carb for reed valve engines. That is because the flow area between the needle and its jet hole was less with the NT than with the Speed. And piston port engines need leaner jetting because their strong-front vacuum waves pull up more gas thru the jets so the jets need to be smaller. For any other carb you need to find a leaner needle (one with less taper angle) if you have a piston port engine because most carbs are sold with a needle that is best for reed valve engines. To see available needles and their taper angles just go to this page, about half way down, and click on the link for the type carb you have and then scroll down to the needle listing: www.dragonfly75.com/moto/carbjetting.html

[@fabiotiburzi]

For the reed valve engine, did you made the window on the piston skirt? That help a lot

[@MichaelForrestChnl]

of course I did

[@MichaelForrestChnl]

Also consider the fact that if the intake manifold has about 5" added to it then the engine will have even more low RPM power. see www.dragonfly75.com/motorbike/EIntake.html