I am not sure which gate it would be but you should be able to take your motorbike a long way up - if you follow the road I would think it will be obvious where you cannot drive any further. That said, we really enjoyed the walk up from the bottom gate, where you could park your bike, seeing the intermediate temples and other sights.

The lonely planet says 1729...I think there is a moving stairway up one side, but we couldn't find it. There are also lots of stopping off points and places to eat and drink on the way up so you can take your time. I hope my response was helpful and not too late. I've only just seen that you had posted this question. Enjoy your trip!

It's a quick trip. People usually go there just to see the sunset. If you take a cab to the top, it could take you just 10 minutes. If you decide to climb the hill instead, it would probably take you around 30 minutes or so.