Speed out of the ground instead of your legs: go light on the rise, press into the bike over the crest and down the back. In a race you're off the pedals about 40% of the time.
Pumping is the base skill that manual, jump and race pace all build on — and it isn't pedalling but pressing and unweighting with the whole body, the way you push a swing. Timing is half the job and is most often done backwards: press on the way up and you brake yourself. The right pattern is light uphill, heavy over the crest and down the back. The other classics are stiff, straight arms that can't pump at all, and looking down, which robs you of rhythm. Practise the movement standing still first — sink low, extend explosively — then on the first roller, then carry it into the berms: light at the entry, pressing into the bank through the middle. The honest test is a full lap with the pedals held level and untouched. If you roll to a stop, what's missing is timing or pressure, not fitness.