I know there are a lot of opinions out there on what oil to use in a Girly (I have read several while searching this topic).
It is very disappointing for me too have two motorcycle manufacturers with oddball oil weights in their owners manuals. I have a Yamaha that "requires" 20w40 which is not a weight you can find anywhere but at your friendly neighborhood Yamaha shop. It is an air-cooled trail bike that only requires one quart of oil and I run Mobil 1 20w50 in it in the summer and 10w40 in the winter.
Since the Tiger manual says Mobil 1 Racing 4T 15w40 is the correct oil to use and only 10w40 and 20w50 are available in most shops and auto stores, has anyone every tried running their Tiger with one quart of Mobil1 20w50 mixed in with 3.2 quarts of Mobil1 10w40?
I use Amsoil Motorcycle Oil in both my Steamer and my Sprint @ 10w40.
The "10" in the oil reading regulates how much oil is available for the finest tolerances at the lowest temperature. Forget about oil pressure. So if you could run your steamer at 0w40, that would be better than 10w40 which would be better than 15w40.
So raising that initial weight only helps protect gaskets and such. The best designed bike in the world could handle 0w100 weight oil because it's tolerances are so good.
My Owners manual says that 10/40 or 15/50 semi or fully synthetic is Ok to use as long as it meets API SH (Or higher) AND JASO MA
Ditto to what Colonel Nikolai said. I run Amsoil 10W40 in mine. The main thing you want to concern yourself with is the service ratings which I think are at the API SH (Or higher) AND JASO MA as Timbox2 said.
Jason
local trumpet shops tell me that the recommended oil is gonna change from Mobile 15W-40 to castrol RS4T 10W-50 because mobile can't keep a constant supply to them
that said, I run Rotella T 15W-40 dino oil (diesel grade oil) and change oil & filter every 3K miles
it's better to have fresh good oil in a motor than old great oil IMHO
and wth rotella @ $13/gal Wally World and a ST7317 filter @ $2.83 it's fast and inexpensive to swap it often
Quote from: "xtphreak"that said, I run Rotella T 15W-40 dino oil (diesel grade oil) and change oil & filter every 3K miles
x2