I want to block off the oil injection and run pre-mix in my '91 Kawi SC650. Can I just let the oil tank run dry and put pre-mix in or do I have to block off / remove the injection system? Any help appreciated!!!!

It would be a good idea to block off the inlet for the oil into the motor/carb as far as the pump  concerned it would be a good idea to remove it and block the opening off from the case, however i don't think it is completely necessary. you may also have to re jet the carb to accommodate the premix rather than straight gas. hope this helps

where exactly does the oil inject?    some systems will lube a bearing that is otherwise hard to adequately lube with premix.

 highmarker, on 16 January 2012 - 04:54 PM, said:

I have an 89 650SX, essentially the same engine right? Mine injected into the carb, about 2 inches down on the outside of it, farthest away from the cylinders. To remove it, simply pull that hose from the carb, and seal the hole up with a rubber vacuum cap like you see on car carbs. Then just take the whole thing off the ski, toss it aside. Some people like to clip the oil pump off of the engine, but i see no need to, mine runs fine without doing it.

Best move you could make to remove that thing. Bought my ski for $100 over the summer. The lines had dryrotted and started pumping the oil into the hull while the guy was still riding. Needless to say i had to order some pistons/rings. But after that she ran like a champ!

I did the same thing.  Purchased the block off kit from SBT.  Real easy to do.  I ended up just pulling the whole oil tank out.  One thing I forgot to do at first was connect the wires on the oil tank sensor.  The Jetski thought it was out of oil and would not let me open it up.