The dreaded oil Question!!!

Post your general FAQs, comments & questions regarding all Ducati engine & transmission restoration here. [Specific engine FAQs should go in the 'BevelHeaven Garage' section.]
Cucciolo - the Lil Pup
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Post by airmale » Thu Mar 02, 2006 5:35 pm

To Colin and all,
Please understand that I am not criticizing anyone for there choice of oil. We all have the information at our fingertips to make an informed decision on this. My only motivation is to gain the knowledge of more experienced Desmo owners. I appreciate the input of all. I hope I have accomplished at least an interest in looking into the resent changes in oil technology, and supplied some interesting reading. I know I have learned much from my resent research, and I will need to make changes to my own standards. It is very hard to simplify such a complex question but, ”for me”; I have been able to reduce it to only 2 items. The following links will be used to make my decision and I post them in the hope that they may be of some use to others. “To all” thanks again for the help, and to Colin in particular “Hats off” for the links and your devotion “ It’s great to see your bike being used, as it should be.

Oil Specs as of 2003, the most recent I could find. ... 7-2003.pdf
This article addressed all my questions on modern oil.

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Colin Linz
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Post by Colin Linz » Fri Mar 03, 2006 6:03 pm


I have enjoyed the discussion; it has provided some interesting reading and a range of thoughts regarding engine oil.

There is a site that has wear tests of different oil on it, but I have lost the link and have been too busy to try and chase it up. They ran the same engine on a dyno in the same manner, then drained all the oil and measured the amount of particulate gathered, then tested to see what the particulate was. In this way they could say if it was slipper bearings, cast iron, aluminium, or whatever. This gave them an idea of how all the oils behaved when it comes to wear and power (fuel economy). Naturally the majority of synthetics performed the best, but the old GTX was better than a number of the synthetics when engine wear was a factor. I can buy GTX3, which meets the API ratings of the Synthetics they tested for about $25 AUD, Mobile 1 costs me about $65 AUD. I was using Mobile 1 in my car until it was brought to my attention that Subaru actually advised against it; apparently it caused excess oil consumption.
Colin Linz

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Post by Spub » Tue Apr 04, 2006 8:27 pm

Very entertaining thread, with a lot of great information. Just thought I would add some perspective from two prolific Ducati writers, Mick Walker and Ian Falloon:

Mick Walker appears to condone the use of multi-grade oils:

"On the classic bevel driven V-twins Ducati recommend a straight SAE40 monograde. This is perfectly suitable, but with the great advances made in oil technology the past few years, a good quality SAE 20/50 is also in order. However, high detergent oils (particularly Castrol GTX) should be avoided."

("Ducati Twins Restoration" page 103)

He does not state an opinion on synthetics, and does not expound on his reason for recommending against detergent oils. From my reading convention wisdom states on older engines with carbon build up the detergents may let loose these deposits in small enough particals that can cause much damage once they get imbedded in the oil film.

Ian Falloon appears also to condone multi grades in bevel twins, but goes one step further and appears to condone the use of synthetics:

"One of the problems with a unit construction engine with all those internal gears was that the oil polymers were stretched to their limit and oil breakdown occurred after a surprisingly short time. This is why Ducati initially specified straight 50 weight oil as the early multi-grades were too thin under extreme use. The improvement in oil technology since these machines were manufactured (especially in the area of synthetics) has made reliance on straight grade oils less necessary, although their use is still countenanced if the machine is run at high speed in extremely high ambient temperatures."

("Original Ducati Sport & Super Sport" page 126)

I would be interested in hearing the experiences of anyone who has run multi-grade synthetic for any substantial period of time. I have heard many third hand horror stories, but very few where someone told me they did themselves and experienced (choose all that are applicable): premature bearing wear, slipping clutch plates, piston bore failure, sweating, shortness of breath, back or ankle pain.....and please talk with your doctor if you should experience any of these, as they may be evidence of serious side effects or conditions...
1982 Laverda 180 JOTA, 1975 Moto Morini 3 1/2 Sport, 1993 Moto Guzzi Daytona, 2010 KTM Adventure 990, 1974 Laverda SFC #17188

Cucciolo - the Lil Pup
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Post by Desmor » Sat Jun 02, 2007 11:40 pm

I'm sorry, but the use of SAE 50 is essential in warm climes! See 'Ducati Tuning' by Steve Eke. I also corresponded with the Silkolene technical department, regarding what oil is suitable for bevel engines. Their recommendation was Hardwicke 50, a fairly high detergent oil, and remember, Silkolene produce all types of oils, if a multigrade was better then they would have endorsed it.
The reason for using SAE 50 is the high loadings on the big end. Multigrade does not cling to the bearing sufficiently to do the job.

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Post by big phil » Fri Jun 08, 2007 2:06 am

hi airmale
according to your research you say the best oil is 20w50 synthetic.i dont know if this is a misprint and you ment to write mineral or if you have a dry clutch in your bike, but the synthetic oil WILL wreck the clutch in a wet clutch bevel or pantah.i know cause i tried it!!!!
i have also tried both multigrade oils and single weight and have had big end problems with both, but i think that the problems are due to other factors and not the oil.
i have also heard that modern oils are so good that it flings off contact patches with centrifigal forces and for these old technology engines you need something 'stickier'.
i will go back to multigrade as when i am travelling on the bike it is really hard to find single weight oil.
nice one

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Post by Spub » Tue May 27, 2008 1:27 pm

I've decided to revive this thread one had kicked this hornet's nest in awhile...that, and I wanted to interject some originality since I've never seen an "oil" thread in a motorcycle forum.

I have been doing a lot of reading on oils, specifically comparing the qualities of sythetics vs. non-synthetics, and mono vs. multigrades. The above discussion started by Airmale and the input from all contributors provided a lot of information that my very unscientific mind needed to cogitate on, and raised a lot of questions in my mind.

It appears the objection to multigrades is the breakdown of viscosity both due to thermal and mechanical loads. Since multigrades start out as a lighter base oil, when they break down they will eventually become a monograde at the base oil level; i.e. a 10W40 will eventually end up as a monograde 10W, after much thermal and/or mechanical breakdown of the polymers that are added to the base oil to allow it to act as a 40W when heated. My reading has told me the following:

--lighter weight oils flow more readily, and therefore circulate much faster through a cold engine than heavier weight oils. This reduce "start up wear", which can be responsible for a substantial portion of total engine wear.

--once circulatated, heavier weight ois (within reason)l provide a more tenacious "oil film", providing superior protection over lighter weight oil, especially once the engine is at operating temperature.
--The bigger the gap between the base oil and the highest viscosity rating, the higher the level of polymers needed to obtain the desire maximum viscosity.

--Due to the uniform molecular structure of sythetics, they are more thermally stable and shear resistant to mechanical breakdown, than mineral oils. They therefore need less "viscosity index improvers" (polymers) to give them the multi weight grade.

--Some sythetics with less than a 30W difference between the base oil and the maximum viscosity rating use little or no polymers. Examples of the are Mobi 20W50 V Twin and Amsoil 20w50, which use no polymers to achieve their multiweight rating.

--The above would appear to indicate that multigrade non sythetic oils, especially those with a low base oil weight (such as 5W 30 or 10W 40) or a large weight differential between the base oil and the maximum viscosity rating, should be avoided in Bevel engines, as the breakdown of viscosity due the shear/thermal forces will reduce it to its base oil viscosity.

--Monograde, heavyweight oil will not loose viscosity (since there are no added polymers to break down), but do not circulate as readily upon start up, thereby increasing "start up" wear.

--mulltigrade synthetics that had no polymers added in order to achieve their multigrade rating have the potential of having a stable viscosity like a monograde, but also being able to circulate on start up like a light weight oil.

Ok, I'm not saying this is gospel, but it appears to me that the main objection to multigrades had more to do with the viscosity breakdown experienced in mineral multigrades, something that is not as much a problem with most sythetics.

While bevels have wet clutches, any synthetic oil approved for motorcycle use has removed the friction/wear additives that cause clutch slipping experienced with early sythetics. I have used synthetic oil in both of my bevels for 2+ years with no clutch slippage.
1982 Laverda 180 JOTA, 1975 Moto Morini 3 1/2 Sport, 1993 Moto Guzzi Daytona, 2010 KTM Adventure 990, 1974 Laverda SFC #17188

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Re: oil

Post by dewjantim » Mon Nov 03, 2008 1:30 pm

airmale wrote:Hi again everyone,
Thanks to Colin and others for the great links and lots of interesting reading. After doing lots of this, my only question is,” Why the heck are you guys using straight weight oil”? The best reason I’ve read to date, is that someone else recommended it. In all this reading, the only recommendations I have seen are “not to use it”. I have found nothing in the design of the bevel engine that sets it apart from most other motorcycle engines, straight weight oil is no longer recommended for use in “any” engine other than lawnmowers, and heavy straight oil is no longer in use in racing. The research I have done suggests the following.

The best oil to use in a bevel is a multi grade synthetic {10W-50W or 20W-50W depending on your climate and designed for motorcycles.

Mineral multi weight oils designed for motorcycles are perfectly acceptable, if the oil change interval does not exceed manufacturers recommendations.

Manufacturers recommendations regarding oil specs should be followed.

“Any” multi grade oil of the correct weight may be used, provided it is changed within 1500 miles.

There is no significant difference between auto and motorcycle oil other than the replacement or additions of some of the antiwear additives. These have not be removed, but changed to comply with new emission control regulations.

“Do not” used a “high mileage” auto oil in a motorcycle, these have additional friction modifiers that may cause a wet clutch to slip, and also may have lower viscosities to reduce fluid friction.

I will suggest the following but I know I run the risk of being crucified in doing so.

The use of straight oil in a bevel is an old school “myth”, brought about from the earlier days of racing and the Ducati engineers failure to keep up with modern oil technology. In fairness to Ducati, multi weight oil was still in development, and they did change their recommendations in later years.

I am really treading on thin ice with the next one.
I am not accusing anyone of anything, I only mention this as a possible reason for an engine builder to recommend such oil, and it is mentioned only for food for thought.

How much business would someone lose by making a recommendation that eliminated their own business? I refer you to the earlier post that has the response from Vee-Two on oil recommendations.

The proof is with you bevel owners, the oil you use, and the reliability you get. I would love to hear more of your experiences.

Tom, I was glade to hear of your similar experience with GTX, FYI Aeroshell 15W-50W semi synthetic is one of the most popular oils in aviation. I know of many owners and businesses that use it. I use Philips 20W-50W mineral oil in both of my aircraft because of the cost factor and the change interval is 20 hours.

Colin I agree with that oil foaming is a major consideration, but nothing will foam oil more then a crankshaft spinning in a wet sump. I would hope that all oil makers dealt with this problem long ago. Thanks for the links, I read it all.
I don't know much about bevel drive engines (yet) but HD recommends either 20w50 or 50 wgt for their 2004 Sportsters. On my Ironhead Sportys the factory recommended 68 wgt oil. These recommendations came from the owner's manual (2004) and service manual (1974). Both these engines are somewhat similar in design to the bevel drive ducati (ouch, let the flaming begin...), both being high displacement v-twins and having low pressure, high volume oil systems. I use full synthetic 20w50 oil in the 2004 with no problems. The 1974 gets 70 wgt golden spectro. It makes to much noise with the multi grade oil. Anyway my point is that at least one motorcycle manufacturer still recommends single wgt oil. I plan to run 20w50 GTX in my 860, if it is noisy (like my ironhead) I will switch to 50 wgt Spectro.....Dewey.

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Post by MartinMille BANNED » Mon Nov 03, 2008 2:28 pm

I have always run my Bevels on straight 50w dry or wet clutch and have never had any problems at all

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Post by Grover » Sat Nov 22, 2008 1:13 am

Martin, what brand of oil are you using? After having my gearbox and big end replaced, I am using Pennzoil GT Street recommended by Ron Young, but I am having soooooo much trouble finding a stockist of it...I have exhausted all avenues and as Shell now owns the brand, its getting even harder to find. I'm thinking i may go back to Motul 1000. I run Mobil 1 in my Honda Blackbird, and what magic oil it is, but you can't compare the 2 engines.
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Post by nottonight68 » Sat Nov 22, 2008 1:43 am

grover-BP corse plus-its the best

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Post by Grover » Sat Nov 22, 2008 1:54 am

Thanks, at least I know I can buy that locally!!!!
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Post by nottonight68 » Sat Nov 22, 2008 2:05 am

i used bp corse plus from new-changed every 2k-done 90,000 on original big end and still going-im convinced anyway

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Availability of Monograde Motorcycle DINO Oil

Post by GHamilton » Thu May 14, 2009 9:09 am

Gentlemen. I have recently had my '80 900SS motor rebuilt and am going through the dreaded "what oil to use for the break in" angst. It currently has monograde 40wt in it for the first 50 miles or so but I neglected to purchase the "required" 50wt before returning to Michigan with the bike. It was redone in North Carolina which as I'm sure you know is home to many NASCAR shops so availabilty of 50wt is not a problem. That said, all I can currently find in a monograde is synthetic and I won't use that in the break in period. Also as an aside, I was talking with Jay Wright of Bare Bones Racing a few years ago at an AHRMA event about problems he had with some of his racebikes that were using air cooled Rotax engines. He was having frequent valve problems and coudn't figure out what was causing them. He then tried a heat sensor gun on the head after a race when the engine had synthetic oil and then with dinosaur oil and the temperature was dramatically lower with the dino oil. He used the dino oil after that and didn't have any problems. He came to the conclusion that the synthetic was not carrying enough heat away from the head as was needed, but the dino oil was. I since then have not used synthetic in any of my air-cooled bikes and have never had any oil related problems. Now to the question.
Will I harm the Ducati motor if I use a motorcycle specific 20w50 Dino oil?
Does Harley Davidson 50wt have the necessary ingredients for the sheer stresses of the Ducati motor?
Who makes and where can I get 50wt motorcycle specific oil?


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Post by BevHevSteve » Thu May 14, 2009 9:19 am

Gordon, you need to make sure you get an "SG" rated oil for use in your bevels.......... multi or straight, dino, semi-synthetic or full synthetic.

SG is what matters the most
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Post by mizike77 » Thu May 14, 2009 11:07 am

So, would a happy medium be an SG rated motorcycle specific semi-syn 10w 50 ?

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