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Which oil should I use.......? No, not really.

I was at the local dealer on Sunday (collecting the most expensive balljoint in the world) and noticed that they had BMW-branded 20W50 oil for sale. I hadn't seen this before. I commented on it and they guy said they have to sell Castrol GP/GPS because BMW have an agreement with Castrol to supply/use their oil for bikes and cars BUT since BMW recommend 20W50 for the boxers and Castrol don't do one, the dealers have started selling the BMW-branded 20W50 (semi-synth, I believe) alongside the Castrol.

I should have asked how much it was, but being in litre bottles I guessed the answer would correspond to more than I was willing to pay.

I've done some research on HD-branded oil and it seems to have come out bottom in a few tests in the US (protection/wear resistance/stability in varying temperatures) so I changed my mind about using that again (plus there isn't a dealer nearby) and ordered some Valvoline VR1 from Demon Tweeks - high performance 20W50 mineral oil for a shade under £20 for 5 litres. Whether it's any good I don't know but it's thick and slippery and should last a few thousand miles.

Here's a question - do I leave the 10W40 in for my dyno session at PDQ and then change to the 20W50 afterwards, or put the 20W50 in before?

Castrol do make a 20/50 mineral oil its called GPS and my local BMW dealer sells it.

However they now advise 10/40 semi synthetic after 12k.

Wish they would make there bloody mind up.

Bob

Hi just bought a 20/50 Mineral from Repsol in Spain....18.90 Euros for 5 litres.
Considering the temps over here, 20/50 of any description is quite rare.. most are 15/40 whether mineral semi synth or fully synth.

Also bought Castrol mtx 75/140 (G5) fully synth for the gearbox and final drive.... 24 Euros per litre... Don't say it.... even had to lie to er indoors.

Don't know why I did this really.. whatever Vines put in it for the prep service.. its great. the gearbox is really slick and quiet... having said that I am rather use to the R100Rs which is incredibly clunky!

Boxadog 2000 wrote:Castrol do make a 20/50 mineral oil its called GPS and my local BMW dealer sells it.

GPS is semi-synthetic. GP is mineral. The only 20W50 bike oil (and note that bike oil isn't necessary in a BM) that Castrol do is CASTROL ACT>EVO GP 4T 20W-50. Which doesn't explain why my dealer stocks BMW-branded 20W50 rather than the Castrol version, except that I think the BMW one is semi-synthetic and the Castrol is mineral.

Boxadog 2000 wrote:However they now advise 10/40 semi synthetic after 12k.

Who do, Castrol? It's too thin - who would you trust for this, the engine manufacturer or an oil company?

Boxadog 2000 wrote:Wish they would make there bloody mind up.

In this respect I trust BMW as quoted in the owner's manual.

sproggy wrote:
Who do, Castrol? It's too thin - who would you trust for this, the engine manufacturer or an oil company?

I'm always a tad wary about exactly who to trust re things like engine oil etc. Sure, I go by manufacturers' figures where tyre pressures are concerned, and as a result have experience better handling and improved tyre life.

Oil?

Ok so it's off-topic slightly but nonetheless relevant: H0nda recommend an oil change on the Blackbird every 8000(!) miles. The 4k service is a quick nut'n'bolt check. A lot of folk state 'Well...H0nda designed and built the motor so they know best'. Then I tell them that the Big H hasn't produced a CCT that actually works for 30+ years. I'll carry on changing it every 4k...

When the owner of a 275k mile Blackbird was interviewed by M*cough spit*N recently he was asked the secret to engine longevity: 'It ain't what oil you use (within reason - 3in1 won't work in an R6), it's how often you change it - keep it clean, it's the motor's lifeblood'. Can't argue with that.

Not all oils are equal. Some car manufacturers (Audi, for example) allow service intervals approaching 20k miles depending upon use BUT only if you use their own VERY expensive oil. Use normal oils and the service intervals are closer.

I used to change the oil in my Blackbird every 4k miles - what's the cost of oil compared to an engine rebuild? But as you say this is a bit off-topic - while intervals may vary depending upon oil quality, the grade of the oil is different and affects how the engine performs and wears from the minute the oil goes in, not after 4k/6k/10k/12k miles. Only the engine manufacturer has run the engine on a dyno for thousands of hours, measured clearances and tested different oil grades.

Changing at 4k is just simply wasting money and resources. That engine was designed to run and last with 8k intervals using the shittiest oil available. Running it with quality synthetic oil would allow you to change it at 16k intervals and still not have any problems with longevity.

Things like allowing the engine to warm up before beating the shit out of it has much, much more impact in how the engine lasts than any oil change.

But hey, if you have the money and it makes you feel good.

throttlemeister wrote:
But hey, if you have the money and it makes you feel good.

I have, and it does.

Oh..and H0nda, for some strange reason, state that fully-synth is not to be used in the Blackbird motor.

That is because it has a wet clutch!

Hi Madman..... In a previous post you mentioned you use fully synth oil... Have you had any problems with the French heat and all?

Stuart

madman wrote:That is because it has a wet clutch!

Nothing to do with at all as it happens. H0nda have found that the Blackbird motor causes fully-synth oil to 'froth' - no one outside Honda seems to know the reason why. Folk who've tried f/s have also noted serious engine vibration as a result...returning to semi/synth or mineral has brought the smooth running back.

throttlemeister wrote:Changing at 4k is just simply wasting money and resources. That engine was designed to run and last with 8k intervals using the shittiest oil available.

Yes, last as long as the warranty period, after which Honda don't really care, do they? Look at any bike that's done big mileage (over 100k miles) without a rebuild and chances are the owner's changed oil more frequently than the manufacturer suggested. Oil does deteriorate in terms of characteristics (some more than others) and it does pick up dirt and other contamination over time and miles. 4000 miles worth of short town journeys is far more harmful to oil (not to mention the engine and the rest of the bike) than 4000 miles of motorway cruising. I can't agree that changing oil more frequently than specified is a waste - it depends upon the engine, rider, use of bike and quality/type of oil. Oh, and personal preference!

snavetrauts wrote:Hi Madman..... In a previous post you mentioned you use fully synth oil... Have you had any problems with the French heat and all?

...and do the bikes use more fully-synth than they did mineral or semi-synth? When I ran Mobil 1 Motorsport 15W50 f/s in my GS (for a track day and a return trip to Jerez) it drank it like there was no tomorrow relatively speaking. Reverting to semi-synth killed its thirst for oil immediately. I believe other people have experienced the same thing?

sproggy wrote:Look at any bike that's done big mileage (over 100k miles) without a rebuild and chances are the owner's changed oil more frequently than the manufacturer suggested.

This is what I was trying to say when I was yattering about the guy with the mega-mileage Blackbird. He'd done the same thing when he owned a 400k+ mile VFR750 ie change the oil every 2k or so. I believe he just used fairly cheap (he'd need to!) stuff but kept it clean by changing it regularly. Would those motors have lasted as long by sticking to manufacturers' recommended intervals? Who knows.

I have heard it stated that Honda use the 8k interval due to the amount of detergent used in modern oils - apparently this is 'burnt off' during the first 1000 miles after an oil change. The detergents aren't, allegedly, good for the motor and to change the oil too regularly can do more harm than good. I have a very large amount of scepticism regarding this - although I may be wrong.

When engine makers develop new motors they may spend 100's of hours on the dyno/being ridden etc but do they leave an engine with 8000-mile-old oil in it for 3 months sat doing nothing to see how it performs? I very much doubt it.

sproggy wrote:
...and do the bikes use more fully-synth than they did mineral or semi-synth? When I ran Mobil 1 Motorsport 15W50 f/s in my GS (for a track day and a return trip to Jerez) it drank it like there was no tomorrow relatively speaking. Reverting to semi-synth killed its thirst for oil immediately. I believe other people have experienced the same thing?

Ditto that here Sproggs - on a 30k mile old R1100R.