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Took the duc out this weekend for the first time in a while. Bike has 15,000 KM on it and besides a set of SIL carbon fibre slip-ons its bone stock. I noticed the clutch slipping in 3rd/4th gear at 7000rpm. I have owned the bike since new and for the most part I don't do too many clutch wheelies so the pre-mature failure of the clutch was not at all expected. After reading some articles from various forums I decided to change my oil. I am pretty sure I had AMSOIL 20-50 synthetic V-TWIN oil in the bike but the oil has not been changed in two seasons. Yes I'm a bad papa!

As a quick test I drained the oil and filter, re-used the stock filter and put in 3 litres of Shell 15-40 diesel, mineral oil. It appears to have solved the clutch slipping problem. I would not have used car synthetic oil in the bike. The old oil was very dirty, it did not smell burnt but it was very dirty. After swapping in the shell mineral oil the bike pulls to the rev-limiter in all gears, without any slipping.

I'm going to think twice before paying $20.00 a litre for AMSOIL, especially if it causes my clutch to slip.

Can anyone suggest a good mineral oil for the 800SS. I might as well pay $7.00 a litre and change it every season. I typically put 2,000 KMS on a season so the extra savings of Synthetic isn't worth it.

Thanks
 

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DON'T use diesel oil!

I had posted a link to an article about it in the oils and lubes section - but the link has died... however - I had quoted the main points.

1) Diesel oil is engineered with a higher amount of dispersant and detergent package to deal with the increased amount of soot and other hydrocarbon combustion by-products present in a diesel engine. This high amount of detergent can increase the decomposition temperature of the ZDDP, which will reduce its effectiveness as an anti-wear agent, especially when a vehicle is used for short trips and does not achieve a full warm-up condition.
Diesel engines are engineered with this constraint in mind, unlike gasoline engines.

3) Additives in oil displace the base oil which is the primary lubricant and hydrodynamic film agent. Some additives will even lower the film strength of the base oil. This is why relatively small amounts of additives are engineered into racing oil, where film strength is the number one design criterion. The bearing journal size-to-displacement ratio on a gasoline engine is designed around the use of lower-detergent oil and relies on a high shear rating of the oil. For a given viscosity, high-detergent diesel oil has a lower surface tension and lower shear strength which can cause increased bearing wear in high-revving gas engines.
A diesel engine needs oil with very high-detergent capabilities in order to hold the large amount of combustion by-products in suspension. Diesel engine oil cannot be optimized for film strength due to this engineering compromise. On the other hand, high-performance gasoline engines do benefit from lower detergent oil which is more optimized for film strength than sludge and soot control.

4) The increased amount of metallic-based detergents in diesel oil can cause excessive ash deposits in the combustion chamber and on exhaust valves. In some worst cases, these deposits may cause detonation. This detonation could be potentially problematic, especially in high-compression, turbocharged or supercharged engines.

And from another article: diesel

Here are the differences between diesel engine oil and gasoline engine oil. In a modern diesel engine there is substantial exhaust soot contamination that the engine oil must contend with. Diesel oil is designed with much higher levels of detergency and dispersency to fight the soot contamination. Like ZDDP anti-wear chemistry, detergents are a surface active chemistry and compete directly for space on metal surfaces, such as the cam lobe and lifter face. So, in practice, the effective level of Zinc anti-wear is a bit lower than what we expect it to be based solely on chemical analysis. Additionally, the ZDDP that is generally used in diesel formulas is primary ZDDP (which activates at higher engine temperatures) since a diesel engine runs predominantly at operating temperature. In a gasoline engine, we must have both primary and secondary ZDDP (which activates at lower temperatures) since the engine will experience a significant number of cold starts. Also, the viscosity modifier polymers that are used in multi-viscosity engine oil to prevent viscosity loss at operating temperature (to protect the bearings) are different for diesel oil and gasoline oil. Diesels operate at essentially the same rpm all day long and need polymers that are shear stable to protect the bearings. Gasoline engines experience many large ranges of rpm during operation and require polymers that have both shear stability and thickening efficiency capability to protect the bearings.
Run with a good synthetic oil - and change your filter when you change your oil. It's a LOT cheaper than an engine rebuild... Think of it as cheap insurance. ;)

FWIW - I use Motul 5100 10W40 or 15W50. And a K&N oil filter ('cos it's got a nut on the bottom which makes it much easier to install/remove). Others here use other brands (Mobil 1 - and other brands) - and usually the same viscosity ranges.
 

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Don't use diesel oils, as stated above, they contain too much of the wrong detergent.

Change your oil at least seasonally, but definitely more often than you did. This means a new filter too. And now that you have "washed" it with that oil for diesels, it is definitely time for an oil change again now.

Use a good quality synthetic motorcycle oil. Amsoil, Motul, Mobile 1, ... these oils are still cheaper than an engine rebuild.
 

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I agree with RockAZ above.

Synthetic is better oil, and it really doesn't cost much more in the big picture.

Does your bike have a wet or dry clutch? If it's dry, then the oil shouldn't affect it. If it's wet, then you should use a motorcycle-specific oil. Note: "V-Twin" oils are not best if you have a wet clutch; they are designed for Harleys that have a separate transmission and the clutch in the primary drive case.

Change your oil at least once a year, even if your mileage is low. If you have to store it for winter where you live, make the change just before storing it.

Ducatis (and Italian stuff in general) require maintenance, and are designed with the assumption that they will receive reasonable care.
Your engine will last longer and be in better condition if you do these things.

PhilB
 

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Agreed....ditch the diesel oil...and put a new filter on too.

Also agree that the Amsoil V-Twin oil is not a great choice either. It's meant for lower revving motors with a separate primary and tranny.

I've used Mobil1 4T 10w-40 in the past, but have recently switched to Motul 300V 15w-50.
 

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I tried the diesel oil route and I don't think my bikes were shifting as well as with Motul.
 
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