Hi,

I've been using Mobil 1 V-twin 20W50 synthetic motorcycle oil in my K100 for several years now. I've read about Shell Rotella diesel oil on other motorcycle sites and am interested in finding out if other BMW owners are using this brand. Diesel oil comes in both conventional and synthetic formulations. Rotella is sold as "T" for conventional formulation and "T6" for full synthetic. Both products have high detergent content (needed to clean diesel engines which have more tendancy to form burning byproducts). I thought this extra detergent content will help keep the sprag clutch functioning long term.

The K100 has a separate oil sump and gear case, and a dry clutch. Many motorcycle owners choose Rotella because it supports JASO MA spec for use on wet clutches and shared oil sump/gear box. This requirement is not an issue for K-bikes.

Rotella is sold as 5W40 which is optimum for the K-bike engine with ambient summer temperatures in southern Ontario.

Synthetic oil is best for long oil change intervals, at least in cars and trucks. Normally, one changes a conventional oil every 5000 km. Synthetic oils can last twice that long. Motorcycles are winterized here in Ontario so my oil gets changed annually, irrespective of the driven kilometers. For the moment, I'm logging less than 5000 km per year on my K-bike.

So, I guess I'm looking for opinions on two subjects:

1) Is anyone else using Rotella or another diesel oil in their bikes? What have been your experience regarding engine wear, oil consumption, long term benefits, etc.

2) Should I use synthetic or conventional considering that oil change intervals is generally annual?

I cant make an accurate comment for the K but i have read that unless the oil seals are all replaced there is a risk that the extra cleaning power of "better" oils could cause the oil to find it's way out.
I use fully synthetic on my Yamaha, I am planning on sticking to what the book says for oil on my K and its going to be racking up 600-700 miles a week commuting to work.
That is unless someone can give a definitive answer...

I'm currently running Delo 400 oil for multi fleet find its pretty good

I had sprag clutch problems after my engine was immersed in salt water for a few hours(long story) and ran it on a diesel engine oil for 10 hours and the sprag has worked perfectly since. It also cleaned the sight level glass!!
I dont see any advantage to running it full time on a diesel oil.

I change to a quality 15W40 diesel oil every third or so oil & oil filter change and have never had a sprag clutch issue, the inside of my engine is very clean, and for some of these reasons I expect that over the longterm the engine will last. There's every reason to use synthetic oils if an annual change is forecast simply because synthetics don't 'break down' as much as dinosaur oil and suspend harmful particulates better than dino oils do. If using dino oil exclusively then change it and the filter more often. Why an annual oil change? Imagine the corrosive acid build up inside of the motor. Get it out frequently for longterm health of the vital components.

There is very little reason to expect oil seepage issues with 'old' oil seals after changing to synthetic oils since about the early '80s when variations of Buna-N rubber made their way into the construction of oil seals. It's a '70s era near-myth that won't die. Imagine an entire industry (oils and oil seals) not being compatible! There'd be engine oil drooling along back tyres and the roadways everywhere.

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Two Wheels Better wrote:Why an annual oil change? Imagine the corrosive acid build up inside of the motor. Get it out frequently for longterm health of the vital components.

I have been told from many different sources -- other motorcyclists, web search, discussions with my BMW service person -- that oil and filter should be changed at the end of the riding season. Here in Ontario, that's around October / November. It should occur as part of the winterizing of the motorcycle, along with gas stabilizer, battery removal and putting the bike away. Over the winter (which are sometimes severe even this far south in Canada), huge temperature fluctuations occur. Sometimes there can be 20 -30 degrees C change in the ambient temperature within a day. Condensation can form on surfaces and the condensation will react with the oil, oxidizing the oil and reducing its ability to protect the engine. Once winter is over, the old oil should be drained and refilled. This regime is what I've heard and read; it can very from region to region. I imagine such a ritual is not ovserved on the other side of the globe in Australia because of the mild climate there.

Two Wheels Better wrote:There is very little reason to expect oil seepage issues with 'old' oil seals after changing to synthetic oils since about the early '80s when variations of Buna-N rubber made their way into the construction of oil seals. It's a '70s era near-myth that won't die. Imagine an entire industry (oils and oil seals) not being compatible! There'd be engine oil drooling along back tyres and the roadways everywhere.

Good to hear. I thought this was a myth. I changed to Mobil 1 synthetic oil back in 2002 and have never experienced oil seal leakage as a result of the switch.

The reason Rotella interests me is primarily the price. Mobil 1 synthetic is generally $12 per litre; Rotella T is $6 per litre. If the Rotella gives the same protection as Mobil 1, I might consider switching.

Rotella is a good brand. Diesel engines thrash the oil and fill it with all manner of nasties. Change it frequently along with a good oil filter and you can use it, as some of the forum members here do, all year round.

I reckon whomever's giving the advice on changing the oil intends that to be when you're putting the bike away and not just an annual oil change, which is what I am reading from your post. The reason is because of the corrosive effects of used oil left in an engine over a longish period of time.

We have down time here too, OZ is not all lightness and warmth, though most people don't bother with fuel stabilisers as much as they should...I think it's because our petrols are not quite as oxygenated as yours are in the upper, more heavily populated regions of the globe, therefore, there's less evaporation going on over a few months of idleness. I've had a tank full of premium in one of my old bikes for a year and a half and no stabiliser in it and it's good to go. Doesn't smell bad at all. Back in No America it'd be furniture polish-smelling, thick jelly by now.

Here's my 2 bob's worth - Shell Rotella is an excellent oil and developed for use in both turbo diesel and petrol engines. It is designed for arduous conditions and is capable of high levels of soot suspension. Myself, I use Caltex Delo Silver 15W40 mineral, also a very good oil and recommended as an alternative by Caterpillar (to their own proprietary lube oil). The 15W40 is more pumpable at low temperatures than the 20W50 grade, another reason to use it. The K engine holds 3.75 litres of oil in a finned aluminium crankase, it has an oil pump very low down in the engine (low suction head, almost flooded suction) and there is excellent air circulation to aid cooling. There are also no extreme temperatures encountered by the oil in our K engines, unlike the Boxers, where cylinder head temperatures can reach extreme temperatures (coppers riding slow etc). This is when synthetics are of benefit as they are capable of handling extreme temperatures moreso than the mineral products, apart from that, espacially in our application, I can see little benefit in the extra cost. I ran the Delo oil in my K100 for 5 years and 75,000 Kms with no problems and no oil leaks. Changed it religiously at 5,000K's along with the filter. My '05 K12LT is now receiving the same treatment, I don't expect to see any problems therre either. Use with confidence I reckon.

I've got Rotella in both the K's right now for the first time. No issues, no other information to report.



RobMack, I bought my Rotella from NAPA. 3 - 4 litre jug case for $17.00 with my discount... (I think that's a really good deal no matter where you are)

club_c wrote:I've got Rotella in both the K's right now for the first time. No issues, no other information to report.

RobMack, I bought my Rotella from NAPA. 3 - 4 litre jug case for $17.00 with my discount... (I think that's a really good deal no matter where you are)

Good to hear your experiences with Rotella.

I checked the local Kenworth Truck Centre here in Toronto and they are selling Rotella "T" in 5 litre jugs for $15.00 and "T6" for $35.00 for the same quantity. Canadian Tire has a sale on at the moment for Mobil 1 15W50 synthetic for $8.50 per litre (normally $12). The Crappy Tire deal looks good and I think I might go out today and hoard some for a rainy day. I don't know if the deal is country wide or not though.

A 5 litre jug of 'cheap' mineral-based diesel oil here in OZ at the local Repco, Super Cheap, Autobarn and the like, usually costs well over $35 and more - on sale! Ah, the (relative) price of life. Enjoy it if you've got it.

Rob, just so you know, that was $17 for all 3 jugs!!

Wow, now that's cheap!! I missed that little detail.