KLIA to KLIA2

I plan to travel from Dhaka to Kuala Lumpur this month (October 2014) on Malindo Air, to connect to KL to Lombok on Air Asia. I think Malindo lands on KLIA and Air Asia will depart from KLIA 2.
I will hopefully have a 4-hour transit.
My question is - how do I go from KLIA to KLIA 2?

There's a train between the two (and into town).

Thank you! I just found out that Malindo Air actually lands in KLIA2, which means no need to transfer.

But you will probably have to go through Malaysian immigration with your bags and check in again. Then exit Malaysia again.
I have done this between AA flights and I think four hours should be ample for this.

Paul

It may not be necessary to go through immigration, if you have carry-on luggage only.
In August 2014 I flew from Denpasar to KLIA2 with Air Asia. I then had a 7 hour wait for my next flight to Australia. These flights were on separate tickets...not a "fly-thru" ticket. I did not have any check-in luggage, and I had checked-in via web check-in.
On landing at KLIA2, I went to the transfer hall reception and asked the officials there if I could go directly into the transfer hall without going through immigration. They told me that as I had already checked-in via the web and had my boarding pass at hand, all was OK. My only concern was that my boarding pass indicated that I needed to go to an Air Asia "Document Check" counter. There was no such counter in the transfer hall, but I had no problem boarding the flight.
So, if you have: (a) carry-on luggage only and; (b)a printed boarding pass via web check-in, then; go to directly to the transfer hall to ask the officials for direct access. If they reject you for any reason, just continue on to immigration/customs.
Good luck.

No worries either way,4 hours is ample.....