wouldnt worry about the packing ,the only difference will be the noise , i wouldnt run 50:1 bit weak i always run 40:1 ,get the best 2t oil you can afford , fresh high octane fuel ,up the street will not achieve a fair result need to ride it as it was designed for realy, without being rude i think you need someone/dad to look at it thoroughly ! hope you get it sorted.