Smooth ramp PW3 cam at 9000 RPM

See the special order "smooth ramp" cam below after a season of racing in an ultra short stroke.


The PW3 cam is popular and makes good power but is hard on the valve train and can cause severe valve bounce above 7000 RPM because of the harsh closing ramps.

The solution was to give it better closing ramps. How better closing ramps were grafted onto the PW3 profile is too long of a story to tell here. The short version is - a careful study was made of the gentle HD XR750 closing ramps before modifying the PW3.

The cam was run with beehive springs and a rev limiter set to 9300RPM and was run over 9000 on the dyno.

A master plate was created for this cam and was hard welded and ground by Web Cam.

Better oil will be used next season.

If the top is 9000 RPM, where is the bottom ?

Cam looks good to me, how much benefit do you think comes from the beehives? Also, what oil was used and what oil will be used in future?
Cheers, Martin

sportsroof said:

Cam looks good to me, how much benefit do you think comes from the beehives? Also, what oil was used and what oil will be used in future?
Cheers, Martin

Click to expand...

The beehives seem to hold revvs better than other available dual springs including popular Norton racing dual springs (as tested on the spintron). The beehives are also lighter weight and thats where the advantage is because they are about the same strength as popular racing springs. There are some high tech special order springs that might be stronger but the higher rate causes more wear and cam flex.

Regular Automotive Mobile 1 was used but Mobile V1 for bikes has a higher rating and that oil will be used next.

See photo of the used lifters below: