Re: Bigger injector
There is a member on this forum that already has a turbo Z125 running so you may want to talk to him about his project. And there is at least one other quality turbo Z125 build on YouTube that I think is from Japan, but there's not much info on it.
I sent a few similar injectors out to have them flow tested recently. The stock Z125 injector flows 105cc/min @ 45psi which seems to be more than adequate up to 143cc. For comparison the Ninja 300 injector flows 200cc/min @ 45psi and bolts right up. I've been running one for a while now on a bigger test engine and the PCV had to pull a lot of fuel out of the map to clean things up, but it runs fine now. Most other Kawasaki style injectors will fit but they flow way too much fuel for these little engines.