No, let’s not revive yet another oil tread. I just like to highlight some of the weasel words oil makers use to mislead us into buying their product. One thing is that I am biased towards HOT WEATHER climate uses ( http://www.weatherzone.com.au/images/climate/wz_clim_annual_site_66062.png ).

For example:

"ENVIRO+ 5W-40 Full Syn.
Viscosity : 5w-40

Approvals:...

. VW 502.00/505.00 (VW http://www.penriteoil.com.au/oem_pdfs/E+5W-40%20VW%20502.00%20505.00.pdf )
. GM dexos2TMLicensed (GM USA)
. Porsche A40
. MB-Approval 229.51(Mercedes )
. BMW Longlife-04

Key Specifications:

· API SN/CF, ACEA C2/C3
· MB 229.31
. VW 505.01"

They give us all the data such as viscosity, synthetic, approvals and key specs, but they hide behind words such as:

a. ENVIRO+ : means that it contains friction modifiers to make the oil slippery and save fuel, therefore "ENVIRO". Not good for wet clutch applications but fine for dry clutch K bikes.

b. Full Synthetic?: Group III, Group IV or V or a mix. It matters. Price and the methods used to make the multigrade oil. Recently I’ve found that in the case of mineral stock they would start with 5w and boost the hot viscosity number with additives. In the case of full synthetic they will start with 40 (5w-40) and fiddle it a bit. So, as additives breakdown, and they do, the synthetic will tend towards 40 weight but mineral will thin out towards 5w.

c. Approvals by OEM:. This is actual approvals REWARDED by OEM and it is important because some OEM specify how long the oil can be kept in the sump before it needs to be changed. E.g. VW and others specify 10,000km, that is for 10,000km the oil must stay in spec. This is a key feature.

d. Key Specs: these may or may not be Approvals by OEM. This is the problem area. What it says is that it meets the specs, according to the oil maker, but there is no formal approval. Hmmm… yes, I know, it is costly, but if you don’t have it, don’t say it. This is done regularly. They often list lots of specs, but may not have approvals for them. you just have to trust them.

So the moral of the story is:

a. Pick a group if they will tell you which (mineral, mineral/synthetic or fully synthetic). Remember that synthetic can mean all kinds of stuff.

b. Get the correct viscosity

c. Look for Approvals REWARDED. For me VW and or BMW LL will do just fine.

d. Get your favourite brand.

Hey Ned, I'm using Penrite HPR Full Synthetic 15w-60.................was constantly getting spragg isssues, but none since swapping to full synthetic, 10K ago (now just shy of 180K). So I'm happy with that!!

andyb wrote:Hey Ned, I'm using Penrite HPR Full Synthetic 15w-60.................was constantly getting spragg isssues, but none since swapping to full synthetic, 10K ago (now just shy of 180K). So I'm happy with that!!

Hi Andyb, I wasn't criticising Penrite specifically. In fact I used them as an example because they provide most info of all oil makers.

Yes, they always state if the oil is suitable for wet clutch application (JASO MA standard) and even provide clues to the synthetic formulation. I am happy to hear about the clutch... HPR is not as expensive (mid range) and is a good candidate for use.

I note that they recommend HPR Diesel 20w-60 or Racing 15 15w-50 for K100
my K1200 currently has Penrite Racing 15 in it and I am fixing to run it until start of winter, about 8 to 9 months.

HI Ned, no I didnt read it as criticising at all, and great info for those of us who dont really have a clue what all those things mean......

I'll find the 15-50 racing for the next oil change!

cheers mate

Our climate in Ireland is quite mild. I use a fully synthetic 10W40 that also happens to be the same specification for two diesel cars. No problems with sprag or anything.

From what I have learnt the biggest thing is that the fully synthetic oils stay in specification much much longer than mineral oils. This is a good thing if you are paying high service costs. But its different if you do your own servicing.

Mineral oils are fine but the service intervals must be considerably reduced. Older cars where mineral oil was used would generally require oil changes at 3-5,000 miles. Newer engines designed for thinner synthetic oils seem to be 10-12,000 mile intervals. If you do have access to cheap mineral oils and use them you must reduce the service interval. I am looking at intervals of 5,000 miles for the K yet a diesel engine on the same oil has a recommended interval of 6,000 miles whereas normally the petrol engine would have a much longer service interval.


The K engine seems to run quite hot and I would certainly look at this more if i were doing a lot of high speed trips in hot climates.
The interval for the K bike seems overspecified given that the sump capacity etc is similar to a car. Thus relatively serviceable oil is removed early. The key to long engine life is frequent oil changes and this must be a key factor in the reputation of these engines for durability.

Ah yes the good old oil numbering confusion systems again
Modern fully synth diesel engine oil are well over spec for the K, the "low sap" oils will clean out everything from the engine including the level glass. They were introduced to cope with the demands of modern injection and turbo systems. IMHO the so called long life oils are a salesmans dream, he can sell fleet cars that never need an oil change before they are replaced.
The K is a pretty basic old petrol engine and a semi synth with a 5000 mile change should be a good choice.
I'm coming from a lot of diesel experience rather that petrol, the only thing petrol round here is the strimmer and the K, even the (1984)lawn mower is diesel

In the US, API and the US auto manufacturers decided to remove some wear inhibitors that contaminated catalytic converters and made it more difficult for their products to pass stringent US and California emissions testing. Unfortunately the reduction in those wear additives made all non synthetic US made oils grade SH and later unsuitable for engines manufactured by European manufacturers. BMW for example notified US customers that use of any oil graded higher than SG would void the warranty, both cars and motorcycles. Harley Davidson did the same.

As a result, the European manufacturers came up with their own oil standards expressed in the ACEA Oil Sequences. For a motorcycle like ours where the transmission and clutch do not share oil with the engine, a pure automotive oil is fine. A JASO rating is not required. For a flat tappet engine such as ours you want an oil rated for service at high temperatures and high sheer rate viscosity. According to the 2012 ACEA Oil Sequences that would be an oil rated at A3/B3 or A3/B4. Here are their definitions:


A3/B3 Stable, stay-in-grade oil intended for use in high performance gasoline engines and car & light van diesel engines and/or for extended drain intervals where specified by the engine manufacturer, and/or for year-round use of low viscosity oils, and/or for severe operating conditions as defined by the engine manufacturer.

A3/B4 Stable, stay-in-grade oil intended for use in high performance gasoline and direct injection diesel engines, but also suitable for applications described under A3/B3.

Extended drain intervals are pushed by European environmental regulations. Disposing of used engine oil is costly and often results in oil going places that are not desireable, like in a hole in the yard, or down a convenient storm drain. Even when disposed of properly it presents a problem to store, haul, and re-refine. Extending the oil drain interval reduces the quantity of used engine oil per year. Truck fleets and heavy duty diesel manufacturers drove long drain intervals, past 20,000 miles in most cases today, combined with high quality synthetic engine oils as a way to reduce operating costs. Even if the oil costs more per liter, (upwards of 40 liters in most big truck engines) extending the drain interval reduces overall oil and filter costs, along with reducing labor costs in the shop and allowing the truck to stay on the road making money more days per year.

Multi-grade oils use viscosity modifiers to allow them to behave like a lower viscosity oil at low temperatures while behaving like a higher viscosity oil at full operating temperature. The way it works is they reduce the loss in viscosity as temperature rises.

An oil like Mobil-1 15W50 synthetic is a 15 weight oil at minimum operating temperature, but while a 15 wt straight grade oil would lose viscosity as the engine reached full operating temperature, a 15W50 is designed to only lose a small amount of viscosity and is a true 50 weight oil at full operating temperature.

Use will wear out the additive package and reduce the ability of the oil to resist viscosity loss as temperatures rise. For the best quality synthetic oils, however, this loss is very minimal over time if recommended drain intervals are adhered to. A K bike engine will live a long time using a Group IV or Group V synthetic oil (Mobil-1 is Group IV, Amsoil is Group V) and a 5000 mile oil and filter change interval.