Why risk it? I'm not saying that it's going to fail but it could. I have yet to hear of pre-mix failing.
I destroyed a top end on my aprilia rs50 wail doing 75mph on the freeway. The cable that connects the throttle to the oil injector (oil amount is variable to how much throttle you give) slipped out starving the of oil. 12k rpm - oil = very smeared piston.