Long redstone timer freezes minecraft

I try to create a long redstone timer. The timer has 2 lines, each line has 71 repeaters at highest delay on the inside, and 1 repeater connecting the 2 lines. The outside has 2 lines, each line has 72 repeaters and 5 repeaters connecting the 2 outer lines, all the repeaters are a max delay. But when I try to use the timer, the game freezes and I have to close out of it and log back in. Also there's a command block making it rain, because the timer goes to a auto wheat farm.