I am not in great need of this information, just wondering of your thoughts on the best bolt-on cylinder kit.
On one hand there is the CT Powervalve 250, which Jimmy Stevenson used as a powerplant to win the Vegas to Reno desert race. Pro quad racer and freestyler Johnny Hale also recently switched to the CT Powervalve 250. Then there is the PSI Performance 265 Genesis kit, which got Harold Goodman and Joe Byrd to drop their sponsors and switch to PSI. PSI Performance has also has made a name for itself in it's awesome snowmobile engine kits. Finally, there is the Duncan PC2000 250 Powervalve kit, which Travis Spader used to take the overall win in the AMA Grand Nationals.
I've heard great things about every one of these AMA legal cylinder kits, so if I had to choose right now, it would be a damn hard decision. What would you choose?

 

One quick note on your info. Harold Goodman did not drop Sparks as a sponsor. He is riding Sparks built engines this year again. He just worked out a deal last yr for 2 races to help PSI. Email me off the board and I can give you more info about his thoughts on the PSI motor as I have talked to him about it. Also Joe Byrd only used it for the one race where he cooked his motor and PSI offered to help him out so they had somebody there running there motor. After that race he used his FTZ stuff for the rest of the year.

 

Really. Thanks for the input. I guess I need to get my facts straight. I've also just recently heard that Harold Goodman said the PSI smaller displacement motors aren't as good. Well, the question still stands. Which kit would you get?

 

for me i do not know right now but for lower cc engines i have heard that psi is not the best. also ct now has (or will soon have) a 350 power valve kit.

 

and fmf has (or will soon) a power valved kit. but i bet more and more will come out soon but if you race you might not want a engine over 265cc because you then will be in the open class.

 

I think the PSI kits have powervalves.

 

What is the advatange ofd the power valve cylinder?I like the "hit" of a 2 stroke and would rather have that than the smoothness of a 4.That is what the power valve does right.smooths out the port timing and makes the power band smoother?I really don't know.Also if I was going to get a new cylinder it would be a paul turner I know it isn't a power valve but I rode my freinds paul turner 330r and it was amazingly fast!

 

Is The Duncan Racing PC2000, available to the public, or just Travis Spader??? I haven't really been able to find any info about it, but the info on the others is easy to find.

I personally like LRD's package, they are all pretty much the same, except for the PSI. IT looks awesome.

 

Yeah, the Duncan PC2000 is available to the public now.


As for the powervalve question, yes, it alters the port timing so there is power throughout the powerband. The reason behind this is so you always have power when you need it, no matter what rpm.
EXAMPLE:
If you had all the power in one area, like a hard-hitting powerband, (ex. in the hi-rpms) then you'd be in trouble if you came up on a double right out of a corner in bottom of 3rd, because the bottom-end wouldn't have enough power to kick you over the landing. Top of 2nd would have all the power but not enough speed for the distance needed to clear the landing. See what I mean. The broad powerband solves this problem. Also, the smoother powerband is much easier to ride and much easier to stay in power.