_@Celica – The interior on the cylinder wall is slightly larger (1.5mm), the outside diameter is MUCH larger, 22mmx20mm. I will be the first to admit that I don’t know too much about porting cylinders, it’s why I sent it out to have it done, see what he did and then see how it preformed compared to from factory. What would you have done?_
Well, the port in the wall of the cilinder isn`t much bigger now. You can fit a bigger carburator, but it won`t work because the port is too small. I dont know what kind of caburator you have? For example: if you have a 16mm, you don`t have a problem.
I enlarged mine for a 21mm carb (almost impossible). i raised en lowered the port, en widened it. I wident it 68% of the bore, how much i raised or lowerd it i dont know anymore.. In this way you enlarge the port so yo ucan run on a bigger carb.
I tuned my K-star for high-end power, that`s why i want a large carburator. I dont know if i said it allready, but here`s what i did to my k-star.
A made a spacer, te raise the cilinder. In that way th timings are higher, withouth hurting blowdown. I wanted my exhaustport on 180 degree, and it was 160 or some. Normally i had to raise the port so high, that the puch wont able to ride. Now i raised th cilinder, my exhasutport came on 173 degree, and raised it to 180. In that way the blowdown is not too high, so i can accalerate out of a corner properly.
Except raising the exhaust port, i widen`t it, for more area. Before the transfer ports open, you want as much burned gasses out of your cilinder. The more area above the transfer ports, the better (well. there are exceptions, but normally this will do).
As told, i enlarged my intake port for a 21mm carb. Also the (i don`t know how to say) "way" to the transferports on each side of the cilinder are enlarged for a better flow.
Because i raised my cilinder, i had to design and make a cilinderhead that falls 2mm (or more) into the cilinder. At last i calculate and make a exhaust, and fit a HPi iginition.
i bet i get around 8hp, but i`m aiming for 10. I don`t go very extreme the first time i build this engine, and after the build it comes on a dyno, so i can see how much performance it gives, and were (low or high rpm). After that i can begin to tune it to what i want :)
If anyone wants more info to make your K-star very fast, please send me a mail ;)