Powervalve effect?

[viking20]

Back in the day when powervalves became a standard thing on mx-bikes,I was fooling around with rally cars and 4-stroke street bikes.
After my son got a 125,it struck me this was our first pv-equipped bike.Im a huge fan of the gp series in road racing,the commentators mentioned during the last race of the season that the only powervalve 125 was the Honda.I guess up untill now these guys could live with a narrower powerband?Just out of interest,have any of you guys got dyno readouts,or just numbers to compare between current "pv"dirtbikes,and earlier "non-pv" bikes? Was it a huge difference when the bikes changed back in those days?

 

[Rcannon]

I think powervalves are wonderful. I am not sure you can compare the bikes of today with older stuff. There were more issues than power. The old suspension was awful. All of the bikes felt fast. The difference for me is this. The older 125's and 250's made plenty of peak power, but it was very difficult to keep them in the narrow powerband. I remember riding a friends Honda CR 125 (the 23 in front wheeled model). It must have been an 81 era. Anyway, the bike would seriously bog unless the throttle was pinned. In comparison, my 1997 YZ 250 feels as easy to manage as the enduro bikes of the time with great topend power.

In short, I feel like the powervalve made the power easier to manage, not necessarily more overall power.