diesel oils in a motorcycle
 

Hi all,
There is a discussion on the use of diesel oils in motorcycles in an other forum that i am part of. This has peaked my interest as Diesel oils may be easier to get a hold of in far a way places (well in comparison to top shelf motorcycle oils such as Castrol GPS). So what do people think of its use? Discuss:

I know nothing so i can not actually contribute to this.

Cheers
Xander

Many modern 4 wheel engine oils (diesel or petrol) incorporate friction modifiers, these can contaminate friction linings, ie your clutch. clutch slip being the 1st noticeable problem.
pure mineral oil, in some cases, doesn't have these, and your bike may be ok.
Whilst in france, i found shell helix plus, had the JASO spec marking, ie was specified for wet clutches. In the UK, SH plus isn't jaso marked, although I'm willing to bet it's the same stuff.
The main difference between petrol and diesel engine oil, is that the diesel varient is more alkaline, due to the more acidic nature of the combustion byproducts. I can't see a problem with using a more alkaline oil, so long as your clutch is ok.
Bikers are getting shafted by the oil companies, there is no reason why, that 4l of basic bike oil should cost more than 4l of car oil.

The manual for my Harley suggests that if it is not possible to obtain the official Harley oil it is better to use a diesel engine oil as it is more suited to an air-cooled engine.
I run all my bikes on diesel engine oil, including the Harley which now has over 60k on it.



________________
C90's,
Riding one is only slightly more interesting than walking

Interesting to see the points on the pH of Diesel oils. however, does this not mean that if you use a diesel oil in a petrol engine, not having the added acidity to neutralise, you will have a more alkaline environment?

I'm sure acids are more corrosive to metals, but can anyone supplemtn my paltry recollection of A level chemistry and tell us if alkalis and metals are a problem.

Either way, I have not yet had to do an oil change on my XR, and the Ural is a dry clutch with a 1940s engine and so can run on cod liver oil with little negative effect...

On an aside I like the complementary relationship between the signatures of the two previuos posters!!

An extract from Mick Extance's 2004 Dakar diary when after burning oil he changed to diesel oil. 14th January stage 13 Bamako – Ayoun El Atrous
I had now decided that I was not going to be able to get my top twenty finish that I had hoped for, but decided to go for first Brit.
By now the bike was starting to burn oil at an alarming rate, the mechanics set about stripping the engine and had ordered a piston from Belgium.
Much to our horror after stripping the engine right back, the piston that came did not fit. Once again my rally was in jeopardy I decided to retire to bed as I needed a break from it. The mechanics worked into the night and patched up the bike the best they could tomorrow was going to be a marathon stage and it was touch and go if I would finish it.
15th January stage 14 Ayoun El Atrous – Tidjikja Non assistance day
Armed with extra rations of food and as much spare oil as I could carry in my pockets I set off, wishes of good luck and lots of fingers crossed followed me out of the bivouac
I began the liaison of 200kms. Once at the start of the special I checked the oil and well over a litre of oil had burned off. I started to refill my oil when a French mechanic who used to spanner for petahansel came over and suggested that I used diesel truck oil as this is much thicker and takes longer to burn. With nothing else to lose I emptied my bottles of bike oil and filled up with the truck diesel oil, and set off on my way into the special, wondering if I would come out the other side.
After 50kms into the special I checked my oil, much to my delight it was still full luck it seemed was finally on my side. The finish line was a welcomed site one I had not expected to see once again without my mechanic I bedded down for the night. Overall placing 47th

intersting dicussion
does the thicker diesel oil not give problems when having a cold start? i mean on a rally you run the enging hot an than start racing for a day, but being a commuter my engine does not get as hot as while racing..

On an aside I like the complementary relationship between the signatures of the post #2 and #3, are you related in any way? or do you meet for fights?

Also noted. :rofl:
#2 has been around for a while, #3 is retaliation IMO, and the Honda SH50 City Express 2-smoker beats them all for fun (also IMO of course).

Despite what was said in one of the previous posts diesel engine oil is usually available in the same viscosities as petrol engine oil. I'm not going to try repeating the technicalities I've read as to why diesel engine oil is more suited to air cooled bikes than car engine oil as I'll probably misquote them, but I'm sure someone more knowledgeable can oblige.


________________
C90's,
Riding one is only slightly more interesting than walking

he started it........

I'm not claiming any great knowledge of motor oils ,however it is claimed that diesel truck oils have additives that cope with higher compression ratios , higher internal engine temperatures, longer service intervals ,they also have higher concentrations of zinc which helps in situations where the engine may be prone to seizing , plus the dreaded "friction modifiers" are absent .
Modern car oils have very low viscosity to aid in fuel economy .
Air cooled bike engines have wider machining tolerances than modern cars and require oils with a higher viscosity range and better shear strength .

Unless you want to run your bike at -20c it shouldn't make much difference .


A diesel 10/40 is the same viscosity as a petrol 10/40 oil .
But synthetics will always give better cold starting performance than regular oils .

I will throw in a few bits of information.
Unlike any other product, the rating, ie SG is the MAXIMUM rating, not a minimum. This allows teh car manufacturers to specify oils with no more than the amount or wear additives that their engine manage ment systems and catalytic converters can manage.

Therefore be very wary of oils that claim to comply with many grades. It means they comply with the lowest grade, not the highest. For instance SG oil can contain up to 12 ppm zinc (which can be crucial for cam lobe wear) SF 10ppm SE 8ppm and sc 6ppm. an oil which conforms to meet all these grades will be sc or worse. If it conforms only to SG It might have 12pp zinc or none at all. IE if oil was petrol, kerosene could be sold as meeting 100 octane as it is LESS than 100 octane.

There is an exception to this. Any oil having 50 grade capability ( ie 20/50) is allowed to exceed the minimums as those oils are designated for older vehicles without engine management systems or catalytic convertors. BMW SG 20/50 dino oil contains more than three times the limit of wear inhibitors and is one of teh best. Harley 20/50 V twin oil is also very good. SG oils can contain the most wear resistant additives. below or above this specification it gets worse.. ie SF or SH oils have less anti wear properties.

Yet I have to service my car every 5000km compared to the petrol version which is 10000km!

In a moment of confusion I once filled my Harley's petrol tank with Diesel - after draining most of it out and re-filling with Premium it seemed to run a whole lot smoother for some reason although I haven't dared repeat the exercise.

Be careful!
 

I have had two bikes seize when using a type of diesel oil known around these parts as "multiversal" or "universal". It is designed mostly for agricultural and construction use, to be used in engines AND hydraulic systems of petrol and diesel engines and equipment. It worked fine in my tractors, but caused two bikes over the years to seize the engines, within 100km of an oil change. You would have thought I would have learnt the first time, right? :oops2:

Regards

Nigel in NZ