What's your opinion on power valve engines?

[flotek]

iv heard the reason the banshee lost its powervalves from the rz designed cylinders was because your not going to be at stop lights or putting around the city streets its design was simple yet effective she riders will be on the pipe at higher rpms than the valve actuates at (rpm) ,with that in mind alot of draggers (LT500 guys) will actually weld up the power valve area and is highly recomenned by alot of custom shops ,some exhaust valves work alot better than others, i never cared for the lt series design of exhaust valves compared to todays modern hi performance dirtbike engines ,iv always felt power valves were mainly low end help for the 2 stroke style power band ,well if you ride woods or need more bottom for torquey technical crap its probably the shizznit,but for high speed dragging youd be in the upper power band already at a high rpm off the clutch,my .02

[Derrick Adams]

eviltwin, you would think that but, everyone that wants to drag race their Z wants a power valve engine. I read up on it some last night, and from what I saw the Yamaha version seems to be the most low maintainance form of exhaust valving, as well as they ran the same set-up from 82-99 in the YZ line-up, so it should be easy enough to keep parts for.

I'll try the swap and see how I like it.

[flotek]

the rz cylinders are by far better than the she ones its alot more than just power valve though ,theres alot more different than most people think, exhaust wont match,must fab up flange adaptors you need all the electricals too,its A servo electrical actuated exhaust valve, port work is more ideal for topend power , much bigger and better designed cooling jackets and head with improved squish band and comperssion ,this is a sweet motor package

[nickxc]

A couple years ago, I had a 2001 xc 700 that had no powervalves and my dad had a 2002 with powervalves, both identical setups, identical clutching and everything the same accept the powervalves and his power came on stronger right off the line and through the midrange. we ran side by side down the lake many many times and no matter what speed we were going if we both hit it at the same time that powervalved xc would start a slow walk right out in front of me. They just made the motor seem like it did everything just a little faster. thats how powervalves made the motor feel. Its a great system and seems to work really well in sleds. If I was going to spend the money I think I would go in a different direction but If you have the jug your good to go. I think youll love it...