Hmmmm.... I have received 3 private emails on this thread asking what I personally use, so although it's against my better judgement to even reply to this intemiable NERPT, I'll offer my opinion on the two synthetic oils I used religiously nowadays....
On the FJR, it's Mobil One 15-50W red (or gold) cap (no starburst label, obviously). It's readily available most everywhere, and when on sale, not too shabby a price.
Between November-April, I'll switch to 10-40W Mobil One MX4T.... PacNorWest winters here in the steppes and plains in the High Desert of eastern Washington can make conventional oils the consistancy of pudding (ok, slightly exaggerating here, but....)
However, for the XX and the R1, I have made the leap to a slightly more expensive synthetic, which may or may not be superior to the MX4T stuff, but I get a woody using it, so.... :lol:
The XX and R1 receive this delicious oil here: Silkolene 4T Pro-4 Plus Synthetic Racing Engine Oil
Yeah, it's probably way overkill on the R1 (where I use the 10-40W version of this Silkolene), but the Blackbird is another story. There are events where I wouldn't be surprised if the oil temp gets overly, brutally hot.... perhaps not over the 305F mark that jastel mentions, but events like BLISTER, White Pine Fever, ect are exceedingly difficult on the powertrain.
Which is not surprising.... loading the bike up to max GVW and locking the throttle at 8500 RPM for 24 to 48 continuous, non-stop hours in the mid-July Desert West.... this is some fairly severe duty, you'll agree. :blink: