More details on port timing?...

[Terrence R]

Well, I've been reading through a bit, I see some info on raising the port timing by using thicker/more base gaskets. I had the oem .5mm when I bought my bike. Purchased a top end kit that came with 3 base gaskets, I installed the thickest (which I think is .3mm?). I did notice the difference. Seems like the bike almost wants to knock a bit due to the high compression. I'm ganna go back to a thicker gasket.
Question is, lots of people are saying to have the top of the piston at the edge of the bottom of the exhaust ports (if desired for more top end). I'm wondering if people mean the outter edge of the piston, or the actual top of the piston, which would be slightly higher than the outter edge.

 

[twowheels]

Well, I've been reading through a bit, I see some info on raising the port timing by using thicker/more base gaskets. I had the oem .5mm when I bought my bike. Purchased a top end kit that came with 3 base gaskets, I installed the thickest (which I think is .3mm?). I did notice the difference. Seems like the bike almost wants to knock a bit due to the high compression. I'm ganna go back to a thicker gasket.
Question is, lots of people are saying to have the top of the piston at the edge of the bottom of the exhaust ports (if desired for more top end). I'm wondering if people mean the outter edge of the piston, or the actual top of the piston, which would be slightly higher than the outter edge.

It's the top of the piston where it meets the cylinder wall.

 

[Terrence R]

It's the top of the piston where it meets the cylinder wall.

So, the outter edge of the top ehh? Not the very top of the piston (which is the top of the dome of the piston)...

 

[Zman]

The piston spends so little time at the bottom of the stroke it make little difference if the piston shrouds the port slightly. You should get a degree wheel and focus on the transfer port timing for your desired power band.