As DickieS says, there's a lot of work going on at the moment to get the track ready for the World Cup and ParaCycling (runs from 22nd to 31st Oct). Tickets are still available for some days, well worth going along to see how the pros do it!
The only thing you're allowed to alter on the hire bikes is saddle height. Too much hassle and too many stripped cranks and bolts etc in the past from people trying to put their own pedals on or fit a different set of bars. If you don't use Look pedals you can hire a set of shoes for £3.50 (they're clean, new-ish and de-odourised after each use).
Oh and remember, speed is your friend, especially when you're at the top of the banking!