I was sent this link by someone the other day... http://www.pit-lane.biz/t117-gp125-caracte...ues-aprilia-rsa If you are into two strokes do yourself a favour and read it!! It is probably the single best 2T read i have found yet... it starts in French but if you persist through to about page 10 or 15 it pretty much becomes English (or read it through Google Translations and be prepared to laugh) Reading this excellent thread has got me thinking about a lot of things... Cylinder heads... I am developing my own thoughts but it was interesting to hear Jan Thiels observations that a sharp inner edge to the squish band was best for combustion. Most tuners insist that a hemisphere is best but i am not so sure. I can definitely see the benefits of angular sections rather than hemispheres and radii. What are your thoughts on cylinder head design? Ports... I keep swinging between boost port opening first or boost port opening last... there is some interesting info in that thread that has changed my mind again. I have been given strong advice by tuners who swear by one or the other, but im sitting on the fence a little now... i need more thinking time Thoughts??