is the JUNO-Di patch can split up to 4 parts? HOW? like korg X5D can split up to 16 parts.....does JUNO D-i can?

Yes the Juno-Di has splits but in two levels: on patch level you can split 4 ones, and on performance level you can split up to 16 patches.

how? can you plss..explain?

i have juno-g but i think they're the same in this way.... you have something, called Performance, and it has 16 slots where you can load different Patches, and then layer that Patches over 16 midi channels or over keyboard

Hi,
I think that to accomplish what Artemiy said, you would need to use the Editor, as from the controls in the front panel will only allow for a basic split (I'm I right ?)

You must use the editor program to do this. The Di by itself has very basic patch editing from the panel (and in menus). To access the full synth editing features you need to use the editor program. Using the editor you can have a single patch use up to 4 tones/osc's.., and you can go in and do very detailed editing on each part.