Sometime ideas are coming when you browsing on E-bay.
Someone was selling a changed TZR cylinder, first thoughts where is it a changed SP cylinder but I was missing the O-ring cutout. It turns out to be, hand made exhaust sub ports.
Contacted the seller and we had immediately a nice conversation, he made more cylinders like this a true hobbyist with the know how to do it.
In rough lines the cylinder is ready, I only want to smooth things a little bid so it has my own thatch on it.
With a fresh one size up piston it should be good to go.
I'm very interested how this one is performing.
This is a experimental setup, as I don't have experience with this kind off exhaust ports
With exception off the C-port
Hope to test it soon
Head volume 12,5cc with a 0,7mm squish
Turns out that it didn't needed it, its now a tiny bid off as you can see.
We will lift the transfer timing to what is possible
A lot off work I should get better tools for this
Someday I will infest in proper tuning material