What oil?
#1
#2
What oil?
You can use any quality 2 cycle oil, but I usually use synthetics. There are too many brands to mention, and the prices vary alot also. You can get a $2.00/Qt store brand 2 cycle oil that will work fine for the demands that most 50s have. I usually use Mobile 1 synthetic, which is around $7.00/Qt. This is probably more than it really needs though.
#4
What oil?
Look for a good synthetic oil that specifies that it is for oil injection..Also try to get an oil intended for an air cooled engine which if I remember correctly contains ash...We have ran Motul 600 in our Viper 90 for a few years with the stock oil injection and it has never fouled a plug.It starts very good and only smokes a little till the pipe gets hot and after that it runs very clean.