If I remember correctly, Yamalube 2t. The local Yami shop can tell you for sure. The stuff isn't really expensive so looking for "more available" options isn't really cost effective unless there is no motorcycle shop within a 30 minute drive. In which case, 3 liters will last a year or more. Most kids don' t ride the PW50 for that long.
just get normal motocycle oil i forget the brand right now but it is white with a red racing bike on the front get 10w-40w for colder weather or 20w-50w for warmer weather you can get it at most gas and corner stores make sure it says four-stroke on the front
yes for the gearbox normally we use four stroke engine oil, some people claim that sae90 are better but i agree with johndoe1222...
the two stroke oil is to mix with the gas ... normaly not used in the gearbox..
Use ATF. It's cheap and it works just fine. My son raced his pw50 all year including a 5th place overall finish and a Silver Medal (2nd place moto finish) at Loretta Lynns last year with Type F ATF in the gearbox and Motul 600 in the oil injection tank.
Ok, I broke out the owner's manual. It says "Yamalube 4 (10W30) or SAE 10W30 type SE motor oil". And you will need about .3 L, so one bottle will cover 3 changes.
I apologize if I have caused any confusion, it has been 3 years since my son has even ridden his PW50, so my recollection is a little fuzzy. I though that Yamaha had a diferent case oil for the 2-strokes. I always used Motul 600 for the engine, it kept things a lot cleaner. I did dump the Yamalube in the case, but I trusted the parts guy I had back then, and never really paid attention to what it said on the bottle.