cant loop a loop in a sequence . Only copies a few notes

Well thats not very clear, but If I have a 4 bar drum beat on my mpc. I trigeer it in a sequence by playing a pad. It will play through the 4 bar drum beat and then stop. Which is fine. But if i want the 4 bars to be repeated say 4 times so it lasts 16 bars I have to manually play it in. I know I should probably start with a smaller sequence and then just copy it. But in this instance i havent. If i do it manually it takes ages and id have to quantise everything. So I thought I could copy and paste the midi info on the sequence edit page. But when I do this it only plays the first 1 or 2 beats in the bar . Do ya get me?
So how do you copy a drum loop through the sequence edit?
It just makes a difference if i have a very long song already completed but you start messin about with different drum patterns.

change the duration setting at the main window