Exhaust Port Top Curve (2 stroke engines)

About Exhaust Port Shape and how to calculate a racing shape that won't eat rings. Please subscribe and visit my web page at www.dragonfly75.com/moto/

[@MichaelForrestChnl]

To download the free Excel spreadsheet go to www.dragonfly75.com/moto/various.html

[@Mroswaldo16]

The area where you said that ring hitting the cylinder port, thats what Gordon jennings said. Good to remove the edges on port

[@darko_122]

how much deegres should 2 transfer ports be to give decent performance with 185 degrees exhaust port

[@MichaelForrestChnl]

I don't take educated guesses. I only rely on the porting calculator that I created. It takes into account the Power Band you want, the top RPM, and it requires the porting sizes because it's the the size as well as the durations of the ports that matter

[@alessdiazlopez54]

I love your channel guy. I have a question here i don't know how to act. I have an old trial bike (ossa), which exhaust port is trully flat at the top and here is my question. This bike should have good low end torque cause is an trial bike, if i make a good curvature in the exhaust port, i rise the exhaust to, obviously, and i think this should be good for high rpm power to, isn't it? But maybe worst for low rpm power/torque to. What should i do? Are my thinkings correct?

[@MichaelForrestChnl]

Yes that is correct. For trials use you should leave it alone but if you want it to have better top end power then raise the middle of the port, making a nice curve.

[@alessdiazlopez54]

@@MichaelForrestChnl okai thanks a lot! But i mean, i want a good low and mid torque, but the flat top of the exhaust is not good for reliability as i learn from you, so what should i do? Leaving it flat for not get worst low end (or mid torque to, maybe?) and keeping the bad rings life, or making a curvature to better rings life?