49cc engine reed valve question

[docjm]

good day! i have a 49cc two stroke engine and purchased a reed valve. I also windowed my piston and ported my the exhaust and intake.

Previously before installing my 49cc I had an 80cc engine which was also ported and piston windowed with a reed valve and works great. I just want to make my 49cc run better for another project I have in mind.

The motor starts but bogs down on WOT and running with minimal power. I noticed that the reed valve barely fits the intake, do i need to further port the intake to make it a bit bigger?

 

[6blueoval9]

A reed valve motor requires a little bit more air and fuel than a non reed motor.

The jetting required fuel wise is usually quite a few jet sizes larger.

The bogging is most likely from not having enough fuel.

Im not sure to what extent you ported your cylinder but overdoing them can also create a bog down as you can lose much needed velocity...porting should be left to high rpm race motors...it doesnt work all that well on the street.

My suggestion is to try some larger jets and see if it improves...im thinking it will and then decide what you can do for an upgraded carburetor or if you can jet large enough to use the carb you have and try to make the best of it.

What reed kit did you buy?..i only ask because they come in a few different variations and you may have gone too big for your application.

Port matching and some blending should be all thats needed to mate a reed kit to a motor.

 

[docjm]

Hi, the reed valve is a CDH brand its similar to an RSE reed valve design. I inspected further and found out that due to the angular nature of the intake port the upper petal of the reed valve is hitting the ceiling of the intake port resulting to it not opening fully, can this be the problem? Regarding the porting I just smoothened out the edges of the exhaust, at the intake side I added a 3rd transfer port and also extended the intake downwards both by etching a groove. The height of the 3rd transfer port is at the lever of the 2 transfer ports on the side while the extended intake downward is up to the end of the cylinder