2 Stroke questions

[nickaloadien]

I’m fairly familiar with these kits but I ordered this new “upgraded” 66/80cc kit from amazon and I noticed it’s got an interesting looking reed valve with carbon fiber flaps.

I guess my first question is isn’t there supposed to be a windowed piston with a reed? I checked the piston and it isn’t windowed.

Also I noticed the gasket is covered a large portion of the intake port. Should I cut it to match or is this done deliberately?

Was thinking of shaving the head down flat to increase compression. thoughts on this?

P.S. My goal is decent low end torque as I have lots of steep hills in my area. I enjoy the high end the 44T sprocket gives me tho.

the help is much appreciated.

 

[ImpulseRocket]

I’m fairly familiar with these kits but I ordered this new “upgraded” 66/80cc kit from amazon and I noticed it’s got an interesting looking reed valve with carbon fiber flaps.

1 I guess my first question is isn’t there supposed to be a windowed piston with a reed? I checked the piston and it isn’t windowed.

2 Also I noticed the gasket is covered a large portion of the intake port. Should I cut it to match or is this done deliberately?

3 Was thinking of shaving the head down flat to increase compression. thoughts on this?

P.S. My goal is decent low end torque as I have lots of steep hills in my area. I enjoy the high end the 44T sprocket gives me tho.

the help is much appreciated.

For 1. yes. With a piston port engine if the intake duration is long enough, or the piston is windowed, a reed is essential for the proper operation of the engine, otherwise most of the intake charge gets forced right back out the carburetor.

2. As long as the area of the reeds is greater than that of the port, it won't hinder performance.

3. You can take some material off of the head, but the better way to do so would be to remove material from the top of the cylinder. I usually only take enough material off of the head to ensure that the flange surface is perfectly flat so it will seal well.

Before doing anything it is a good idea to measure your squish gap so you have an idea of how much material you should remove in the first place.

My own 2 cents on this motor, given that it has a steel sleeve cylinder. If you care about the performance, you will want to definitely clean up the ports so that the sleeve and the ports themselves match, and chamfer the port edges as they look very sharp in your picture.