im sure there is plenty of debate on this issue.
however if the oil lines are long enough and the oil pump isnt all corroded up, i would run the injection. running pre mix is a p.i.a. in my opinion.
in all the years i have worked as a certified yamaha tech, i have never seen a twin cylinder yamaha oil pump fail. i have seen oil lines come off, but just like fuel lines, its a wearable item and should be replaced when needed.
if your an enthusiast and your not competing, i see no advantage to running pre mix over oil injection, other than the premix doesnt seem to go bad as fast as plain gas.
keep in mind with premix, you are always running the ratio of oil to gas that is mixed. with oil injection, as the motors rpm increase and decrease so does the ratio of oil to gas. in other words, less likely to foul out spark plugs, load up, and smoke you out when your idling around or going through a no wake zone.
i ran the stock oil injection on my blaster with factory pipe, msd enhancer, and other goodies without a problem for years. my oil tank finally cracked, so being a lazy a$$ i just blocked it off.
