You'll need to remove the oil pump because the pump gets its lubrication from the oil that its pumping.
Why do you want to remove the oil injection system? It's a very reliable system and if you remove it you will need to premix, you'll use more oil, and the ski will smoke more. The disadvantages far outweigh the advantages.
If you do remove the oil injection system you'll need to leave the oil tank in so the rotary valve gear gets lubrication.
Lou