Oils aint Oils

[gdayjr]

I am changing the oil in 2005 gs with 70k on the clock.

The dealer says use Shell SX4 15W-50.

So many people have told not to use it because it breaks down too quick in big bikes.

So, any info on the most popular oil being uswd would be greatly appreciated.

What is the best oil for these bikes?.

Thanks. Graham Day.
Sydney Australia.

[AdamWebber]

I use Mobil 15w-50 in my '05. I have 35k miles on the clock though. I wouldn't recommend full synthetic for a BMW during the break-in period - less than 20k. You're okay using synthetic with over 70k.

You don't have a wet clutch on the GS and the red line is about 8 grand. No overhead cams or shims for high-performance. In my opinion, buying motorcycle-specific oil is a waste of money. A simple full synthetic is fine.

You will probably get lots of conflicting opinions in the oil department. I may have opened a can of worms just replying to this question. I've seen lots of posts regarding oil in the past on this forum.

One thing in particular though... On Japanese bikes with lots of miles on the clock, full synthetic oils tend to leak more. It's like the molecules are smaller and fit through the seals easier. If you have that problem, try using a semi-synthetic. The blend is like a combination of large and small molecules. The large ones plug up the seals and keep it from leaking too much. The synthetic portion provides the proper lubrication that the bike should have.

[Schtum]

Interesting that your dealer is recommending a Shell oil. I thought that the BMW recommendation of Castrol Oils was global. Here in the UK, dealers now use Castrol Power 1 10W-50 fully synthetic as the preferred option.

If you're going to be riding in high temperatures then I suspect that 10W-50 offers a bit more protection than a 10W-40 oil. ISTR that there's a 10W-60 fully synthetic by Putoline if you want an even wider viscosity range.

HTH

[gdayjr]

My dealer is dealer of the year for so many years, so i thought he might know what he is doing.

The manual does say use Castrol. and i have used Castrol in all of my vehicles, cars and bikes, and have never had an issue. So maybe time to get it back in there.

After having the 60,000km service done there, i have decided that i probably do a better job than them, so it will never see a dealer agaain. I hate being lied to, and treated like an idiot. Especialy when you catch them out ripping you off.
1500km later, the generator belt broke, and i found a bolt in the generator cover. It looks like the bolt tore the belt off the pulley, so i took them both into a big dealership, to see where the bolt came from.
The guy had all the drawings on the screen, and that bolt (M8x30) is not even listed anywhere near the generator, so another mystery.

New belt fitted, and now doing my own servicing. $40 for a 9 inch belt, just because it was from a BMW dealer. Get real.