This is what the dealer parts guy told me

[Dutter]

i couldn't find the trans oil I wanted out front so I asked the guy to get me a quart for my 2000 Blaster and he brings me a qt of Yamaha 20/50. I told him I wanted thinner and synthetic and he wouldn't sell it to me. His comment was you would be wasting your money on it. I can't believe he try to sell 20/50??

 

[Awk08]

there's a reason he's selling parts and not installing them
and also why it's refered to as the "stealership"

 

[speedyslyder]

the yamalube trans oil plus is 20/40w
i have ran it in my yz250 and blaster
but the manual does say otherwise.
my belief is this heavier weight,clutch life is screwed
and gears in tranny's don't just go out
they have some crazy wieights going on at the dealers
a guy at honda dealer told me i could just run atf in cr125
another guy recommend 85 weight