Thanks for the info my friend, I've heard the same more or less identical, rare, but always negative impressions about Repsol lubricantsThe Repsol Racing was very similar to the Castrol Power 1 I tried at the time (3 years ago or so) I used to run the Repsol in my R125, so it didn't really matter, it was just really cheap and had fancy colours on it, back then I didn't really know much about oils. That said the Repsol always seemed really thin compared to equivalent grade oils from Motul, motuls are very thick generally, and the repsol would regularly need refilling both in my a small top up in my 125. In the ER6 it only started going near the end of life, but to the degree, where up to 4k miles, it was perfectly on the dot every time, after 4k mile you'd need to put almost 300ml every 500 miles. Castrol did the same, but none of the motuls i've had, except the very low grade 5000 one, but i'm willing to give that the slip because it's semi-synthetic and was used during the winter and it was still lesser degree. The worst example of the Repsol Rider 20W50 though is in my 2003 XT600E, big thumping single cyl, probably nice and loose, with 40k miles on it, that thing was CHUGGING the repsol. Blue smoke on startup, and good thing it has oil stored in the frame because, damn it needed it lol. Repsol was going at like half a liter/ 500 miles from the very start. The repsol only stayed in for about 1500 miles before I ran out of leftovers from the bottles and decided to F it, and went for Motul 7100 20W50. No smoking since then and doesn't drink oil anywhere near as much.
About the Shell, as I said they make BMW's recommended oil and their own version is very close, to it. I've always thought of Shell in the back of my mind as a cheap oil company, kind of like Tesco own brand oils or stuff like that when in reality I know they aren't, it's just a perception thing, so i've been reluctant to try them yet, but I also only hear praise for the Advance Ultra and the Rotella in the car industry. In all fairness I used their Advance 2T in my old RG80 2 stroke but that thing is probably even less representative than the XT600 lol
As for fuel economy, I've not noticed any changes in fuel economy on my ER but i think I also have bigger factors affecting it already. In comparison with the XR the average consumption is about the same, on the ER6: I used to get 45mpg (6.2L/100km) as I used to do 150 miles to the tank and then put in 14.8-15L at the pump. The best I got out of a single tank was 189 miles and only 14.5 went in so that was 59mpg or 4.8L/100km, the absolute worst was 118 miles for 14L, so 38mpg, 7.3L/100km.
The XR on the other hand is a lot more sensitive the type of riding you do, but overall has the same averages and consumptions, I haven't really bothered calculating MPG for it because it has an onboard fuel economy calculator and it's pretty much perfectly accurate, the worst I've seen was 37mpg (7.6L/100km), the best I've seen was 53mpg (5.3L/100km), average over 5000 miles according to the Navi was 44.4mpg (6.4L/100km) So I don't know if my ER was pretty bad, or my XR is amazing lol. From what I hear people struggle to get their R1s, MT10s, ZX10Rs, CB1000Rs above 35mpg so this seems extremely good to me. On the other hand ER riders all report around 55mpg and 160-170 miles out of a tank. I think back when I joined this forum I even made a post about my fuel economy lol.
So about the same.
In Greece Shell is not viewed as cheap but more as a "car" brand and the same goes with Michelin when it comes to tires.
If a 160hp four-cylinder literbike is anywhere near as economical as an Er6 then BMW deserves many congratulations! To my mind and experience, this is very hard to achieve even under ideal conditions but I guess modern technology works wonders.
I am not into calculations either but my best ever "performance" was 312km with at least a couple of liters left in the tank, so around 360km of projected max range and running on fumes. That was during a trip, riding mostly on country roads and with the bike loaded, so under similar conditions and without the bags maybe even 10 - 20km more theoretically.