Cylinder Suggestions Help?!

[dirtworxboy]

Hello everyone,
I am new to this but find this site to be very helpful. Now i've been searching through forums after forums and found some good information and was debating to start this thread or not, but as you can see i decide to anyways.. lol. I just want to be positive before i go and make a 800 to a 1000 dollar purchase on this topic. I have a 86 trx250r that i completely rebuilt from the ground up for mx, because that is mainly what i do with it. I am looking at many different cylinders such as ESR,LRD,SPHYNX, and the PUMA. I was thinking a 330 but the question is, What cylinder and bore size will be the best for racing on mx tracks? And another, should i go power valve or non power valve? It has a whole new bottom end with a 4mm stroker, along with v-force 3 reeds and a paul turner race pipe. The cylinder that is on it now is not going on it. I've been stuck on this for about 3 months and hoping you guys could help me out! ps: added a couple of pics so you see what it looks like so far
Thanks, Tyler

[450eater]

A 310 or 330 power valve would work great for mx. Might need a different pipe tho. I wouldn't use a sphinx or puma...they are more for duning and drag engines. The esr or pro x cylinders would be the best to use. But I wouldn't count out a good ported and flowed oem cylinder. They can make great power when ported by the right person. Build it with a lot of compression and run it on race gas and the cr ignition. By the way, that's a good lookin' r you're building!

[dirtworxboy]

Thanks! I appreciate the help

[Burns350R]

I have a ESR 330PV (brand new sleev) top end kit in the fs section for a good price. Lots of extras.

[dirtworxboy]

just checked it out and its pretty nice. Do you have anymore photos of it then whats on the thread you posted? Top,Bottom,Exhaust,Intake manifold? What kind of port job is done to it and did esr do it? Thanks buddy