Quote:
Originally Posted by wayanlam
well the piston i was hoping to use is a FAIL, lol....
thankfully it was tested on some other bike and not mine.
after 2 or 3 weeks of messing about and trying different settings, alll they were able to gain out of these new pistons is a -2Hp (yeah, it lost power, rofl).
they expect that its due to the low quality material used... since as far as the shape is concerned, it should have been good. bigger bore (64mm instead of 62) and a slightly bigger head, increasing the compression ratio. anyhow, im sure there is lots and lots of research required to be able to build pistons that gain power over stock, something that this manufacturer obviously doesnt have enough of.
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Wayan, I don't think it's the quality of material, but the piston itself. The picture speaks a thousand words. If you look at it, you can see all the casting flaws in the piston. It looks to be coated with something as well, probably a ceramic coating. The problem is, you can't just coat a badly casted piston and think it's going to work. The piston needs to be very smooth because other wise, it creates hot spots on the piston which leads to pre-ignition. I've replaced pistons on my old car with oem mitsubishi ones. Even though it wasn't all nice and polished like the aftermarket ones, it was still extremely smooth.
I think it's best in the end if you do get the porting done first and get it tuned. That way, you will know how much each component affects the bike. If you get it dyno-tuned, then you'll be able to tell if the new displacement and CR made a good difference or not. Same with the porting.