The good oil on lubrication
What oil should you use? When should you use it? Why are oil changes important? How to do it – Spannerman answers the tough questions.
Advertising has a lot to answer for when it comes to the confusion many riders have on the issue of lubrication. Older readers among you might remember Peter Brock holding up a handful of dirt and telling us via the television screen that mineral oil comes from soil and you wouldn’t want to put that in your engine. He was, of course, spruiking synthetic oil.
Then you had images of horses running free in fields with the message that a particular oil would “liberate” the power somehow hidden in your bike’s engine. What about the “race” the oil has to get to an engine’s vital moving parts after a cold start? One oil would get there faster.
Various race teams use (or claim to use) particular brands; exotic racing is a key area for brand promotion.
Meanwhile, back in the real world, as you wander the aisles of your favourite supermarket, you’ll find its little automotive section where four litres of house brand oil can be as little as ten bucks. All you know about what you should use in your bike is from the owner’s manual and it says 10W40 with at least an SG classification. That’s exactly what’s written on the home brand oil label. Why are the brands of oil in bike shops four times this price? What the hell is going on?
In the beginning…
The main purpose of oil in your bike’s engine is to reduce friction and wear. It also does other things including dispersing heat and keeping the inside of the engine clean from rust and corrosion. Without oil, your engine would only run for a handful of seconds. The pistons and rings would get so hot they’d weld themselves to the cylinder bores and the engine would stop, probably forever. Lubrication is critical to the functioning of an engine and managing the lubrication is the secret to a long and happy service life.
All motorcycle oils are made up of a base stock and a selection of additives. In a milkshake, the “base stock” is milk to which you add other components (ice-cream, Milo, flavouring, fruit etc) to get the taste you want. With oils, the base stock is mixed with additives to get the performance required.
There are two main types of base stock used for motorcycle oils: mineral and synthetic. The mineral base stock come from oil extracted from the earth which is then processed at an oil refinery. Synthetic oils come from laboratories rather than the earth – they’re made from chemicals.
Before they go on the market, both base stocks are blended with additives designed to make the lubricant more suitable for its job.
Here are some examples of additives. Oils have detergents added to keep the inside of the engine clean as the oil circulates. The muck from the cleaning process, though, can’t be allowed to collect in any one place as it might block the small passageways through which the oil flows. To stop this happening, a dispersant additive is included so that contaminants are held in suspension in the oil. Think of it like a glass of lemonade: the bubbles are in suspension all through the liquid – they don’t just sit in a lump at the bottom or the top.
There’s a surprising amount of moisture inside a motorcycle engine and this can lead to rust and corrosion. Rust prevention additives are included to counter this.
Anti-wear agents are also added along with anti-foaming agents and additives designed to help the oil survive extreme pressure.
What we end up with is a “cocktail” product designed to meet the lubricating needs of our bike’s engine. Contrary to what advertising might lead you to believe, motorcycle engines have specific requirements and all brand-name motorcycle oils have similar solutions. No, they’re not all the same but they all have a lot more in common than the advertisers would have you believe.
Reading the numbers
Your bike’s owner’s or workshop manual will give you the basic information you need to help you select the right type of oil. Sometimes, the manufacturer will specify a brand of oil but, mostly, it will simply tell you what specifications the oil should have.
The manual for our workshop bike, the Hyosung GT250 Comet, tells us the correct oil will have an API classification of SL or higher, and an SAE rating of 10W40.
API stands for American Petroleum Institute and the “SL” grade has properties suitable for engines from 2001 onwards. Depending on the age of your bike, the recommendations might include SF, SG, and SH. Newer bikes might have SM or SN grades specified. Nobody knows what will happen when the API gets to “SZ”. Don’t use an oil of a lesser grade than recommended but you can use an oil of a higher grade. If, for example, an SG oil is specified, an SL would be fine.
The SAE (Society of Automotive Engineers) rating of 10W/40 tells us of the advised viscosity. Viscosity (for liquids) can vary from light (water, for example, which is easy to pour) to heavy (honey). The recommended 10W/40 tells us that the base oil has a viscosity of 10. Typically, multigrade oil for motorcycles might have viscosity numbers ranging through 5, 10, 15, 20 and 25. Honey would have a viscosity of about 180! The higher the number, the heavier the oil.
The “W” stands for winter, and a 10W oil means that in low temperatures, the oil’s viscosity won’t be reduced (much) below that number.
The second number (in the Hyosung’s case, the 40 in 10W40) tells us the viscosity of the oil when it’s hot. Viscosity index improvers are added to the base stock so that as the 10 oil’s temperature increases, the oil develops the protective qualities of a 40 grade oil.
The lower the first number is, the easier it is for the oil to get around the engine. The higher the second number is, the more protection is offered at high temperatures.
I know what you’re now thinking: why aren’t all oils 5W70?
Very low viscosity oils allow for easy starting and better fuel economy because they don’t make the engine work as hard to push the oil around but they don’t have the protective qualities of higher viscosity oils. A 5W70 oil would need an additive pack that could, potentially, make the oil fragile. When the additives were exhausted (more on this later), you could be left with a very light oil incapable of offering the protection the engine needs.
The Hyosung has “10W40” cast onto the screw cap where oil is added to remind owners of the recommended grade.
Why change the oil?
Oils in high power output motorcycle engines work very hard and eventually become tired and emotional. The additives get used up as they work – there’s a limit, for example, to how much junk the dispersant package can carry before it fills up. After this, the sludge-forming residues can attack the engine itself.
Heat and contaminants like carbon, acids and water which are by-products of the combustion process eventually start disturbing the chemical structure of the oil. A 20W50 oil, for example, can end up being a 20W30 which places great stress on the qualities of the base stock.
All manufacturers will recommend oil change intervals – the number of kilometres or, sometimes, the elapsed time, between oil changes. These will vary from manufacturer to manufacturer but 6000km is now common. Hyosung says the oil in our Comet should be changed initially at 1000km and then every 4000km. This is a pleasingly conservative figure but for a bike like this with a 1.5 litre oil capacity, there’s an argument for a change at 3000km intervals. Following the manufacturer’s recommendations is relatively safe but they can’t anticipate how the bike will be used. If you ride at continuous hight speeds in hot and dusty conditions, changes should be far more frequent. Similarly, if your day trips are short and the engine never gets a chance to warm up properly, that’s another good reason for more frequent changes. Having said this, modern engine oils are genius products and you shouldn’t fret if, for whatever reason, you occasionally slightly exceed the change intervals. The bottom line, though, is that changing the engine oil is probably the kindest thing you can do for your bike.
Between change maintenance
Between oil changes, you need to check the oil level in the bike’s engine to ensure enough oil is there to provide effective lubrication.
The owner’s manual will tell you how to do this for your particular bike but common methods include a “sight glass” at the bottom of the engine on either the left or right side (see pictures) or a dip stick not dissimilar to that used on a car but usually much shorter. Your bike should be upright on its centrestand or paddock stand while you conduct your check.
If your engine has a sight glass, it will usually have an upper and lower mark stamped or cast next to the circular window and your job is to keep the oil between these two levels.
With a dip stick, remove the stick, wipe off the oil already on it, replace it in its hole (but don’t screw it in), withdraw it and check the level at the bottom of the stick. There will be marks for maximum and minimum levels and, as with the sight glass, you need to keep the levels between these two marks.
Most indicators leave a fair margin of error so as long as the level is between the two marks, you don’t need to be concerned.
Overfilling – exceeding the upper limit line, won’t provide any additional protection and may actually have a detrimental effect on the functioning of the engine – your boots may end up covered in oil.
Here’s a small tip: the engine oil gets contaminated over time by moisture and unburnt fuel, keeping the oil level sometimes artificially high. If you go for a long ride, these contaminants can be burnt off, making you think you’ve suddenly got an oil consumption problem.
Normal oil consumption will vary from bike to bike. Older, air-cooled bikes like a Kawasaki 1000 can use up to a litre per 1000km without it indicating any particular engine problem. A modern, liquid-cooled bike engine may not appear to use any oil at all between changes.
If you think your engine is using too much oil, it may have a mechanical cause like damaged rings, bore wear, or wear in the cylinder head. Take it to your bike shop for a check. It may also be that the oil you’re using has too low a viscosity. Changing from 10W40 to 15W40 or even 20W50 with mineral oils may reduce oil consumption.
Which oil for me?
The marketers are all out to get you but, armed with the ammunition you have so far, you’re already in a better position to decide what is best for your bike.
Step one is to follow the manufacturer’s advice. If it suggests a brand of oil or an oil type (full synthetic) go with the flow.
Some manufacturers (Harley-Davidson and Yamaha are two examples) sell oil under their own brand name. I’m sure it’s fine to use but the manufacturers don’t actually make the oil – they just brand the oil they get from an oil refiner. Exactly the same oil will probably be available elsewhere and be cheaper without the bike brand on it. Everyone pays a premium for Nike t-shirts but are they any better quality than t-shirts from the same factory without the brand?
Importantly, though, you should buy an oil that has been specifically formulated for motorcycles. Most bikes share the same oil between the engine, gearbox and clutch. Cars have separate oils for the engine and gearbox. Motorcycle oils need to have an additive package that takes into consideration the crushing the oil gets while it’s lubricating the gearbox and the oil shouldn’t have friction modification additives as these have the potential to make the clutch slip.
Any marketer with any sense has a picture of a motorcycle on the label of the oil packaging (memo to Castrol – up your act) which makes it easier for you to differentiate them from car oils.
Yes, they tend to be more expensive than car oils because bikes are about ten per cent of the car market so we pay extra because sales volumes are relatively lower.
Branding does have some advantages in that established brands can’t afford a loss of reputation through releasing a product that doesn’t do its job.
Possibly the hardest choice you’ll have to make is whether to use mineral oil, semi-synthetic oil or full synthetic oil.
The pecking order here is that mineral oils tend to be the least expensive, semi-synthetic (usually a blend of mineral oil with 20 per cent synthetic base oil) next and full synthetic the most expensive.
Some manufacturers make recommendations in this area. Triumph, for example, recommends a semi-synthetic oil for the running-in period to allow all the moving parts to bed in properly and then a change to full synthetic for the rest of the bike’s life. Other manufacturers (Honda is an example) simply nominate the preferred specifications and leave it up to you to decide if your oil will be mineral or synthetic.
In normal riding conditions and with oil changes at the manufacturer’s specified intervals (or less), mineral oils will provide everything your engine needs for a long and happy life.
Full synthetic oils have some documented features that may make them more suitable when your engine operates at extreme temperatures. They’re stable at very high temperatures but maintain their viscosity when things cool down. They have the potential to perform for longer at a high level but keep in mind that if you change mineral oil (and synthetic oil for that matter) at the recommended intervals, it’s a feature you’ll pay for but probably never use.
I know what you really want is brand recommendations so I’ll give you a couple but this shouldn’t be considered a criticism of other brands on the market.
Shell Advance Ultra is a regular advertiser in MT and if it’s good enough for Valentino, it’s certainly good enough for me. Mobil 1 is another full synthetic which modern Harley-Davidson riders swear by but, unlike full-synthetic Shell Advance, it’s not suitable for motorcycles with a wet clutch (most bikes).
The oil I’m using to impress the girl in the picture at the beginning of this story is Castrol Activ4T which is a good, general purpose oil for older four-stroke bikes.
I’ve been critical of Penrite for years for taking its eye off the motorcycle ball and they’ve finally responded (I’m taking all the credit) with a new range of motorcycle oils. Penrite is an Australian company and takes Australian riding conditions into consideration when formulating it oils. It’s a family business with a fine tradition and reputation. Visit its website for more details.
Time for a change
Okay – you know enough now to select a suitable oil for your bike and you know when you need to change it, but how do you actually do it?
What follows is an oil and filter change for our Hyosung but the general principles will apply to any bike.
We’re changing the filter at the same time as we change the oil because its job is to filter out the grunge picked up by the oil as it travels around the engine and keep it in a safe place so that it doesn’t get recirculated. Some manufacturers recommend a filter change with every oil change but if you’re changing your oil at 3000 – 4000km intervals, a filter will usually last two changes.
All the parts (excluding the oil) for an oil and filter change on the Hyosung come to the princely sum of $15 so there’s no real excuse not to be generous. I have to say it’s nice to get what’s needed for a comprehensive service for so little money. I note that Yamaha is currently advertising an oil change kit which comprises everything you need including the oil for a very reasonable price. (Memo to Yamaha – we have a page spare for the ad.)
Unusually these days, the Hyosung GT250 Comet also has an oil strainer as an added safety measure but this time we’ll change the oil without cleaning it.
Here’s the 12 step process:
1. Select the type of oil you want and check your owner’s manual to see how much of it you’ll need. Usually, if you change the oil filter at the same time, you’ll need a little extra oil. The GT250 Comet uses 1450ml for a straight change and 1500ml if the filter is changed at the same time. If your preferred oil comes in one litre bottles, two of them will provide the change and give you some extra for top-ups during change periods if necessary. A four-litre container might end up being cheaper than two one-litre bottles – it’s worth checking.
2. Visit the local dealership that stocks your brand of bike and ask them for an oil and filter change kit for your particular model. For the Hyosung, that includes two rubber 0-rings as well as the filter itself. You also need a fresh washer for the oil sump plug. The Hyosung filter is a paper element but many bikes now come with solid, screw-on filters.
3. Use your owner’s manual to help locate the oil drain plug (it’s usually at the lowest part of the engine) and the oil filter. The filter on the Hyosung is very conveniently located on the side of the engine (see picture). Check the size of the drain plug and the nuts holding the oil filter cover. For us it’s 17mm for the drain plug and 10mm for the oil filter cover. Assemble the tools you’ll need for the procedure.
4. Go for a ride which is long enough for your bike’s engine to reach its normal operating temperature. This helps the used oil to drain completely from the engine (remember viscosity?).
5. Secure your bike on either its centrestand or the paddock stand you bought after episode one. The bike has to be upright (not on its sidestand) for the oil change operation and it has to be stable so it won’t fall on you while you’re lying underneath it.
6. Place a container large enough to collect the used oil under the bike. You can buy these at most stores like Kmart but you can make your own by cutting the side off an old 4-litre oil container (making sure you leave the lid screwed on!)
7. Loosen the plug where you will be pouring in the new oil, then undo the sump plug at the bottom of the engine. It’s a good idea to wear disposable rubber gloves for this as well-used oil can be harmful to your skin and other parts of you susceptible to cancer. The plug undoes in an anti-clockwise direction and may require some encouragement to snap open. Use the correct-sized socket spanner and apply increasing pressure until you hear or feel it release. You’ll be lying on your back while this is going on. The plug and the oil will be hot so your job is to try to undo the plug (use the right sized socket with an extension attached) without dropping it into the oil container or letting the oil run down your arm. You’ll probably get the technique right by the third attempt but it still happens to me occasionally after 10,000 oil changes.
8. While the oil is draining into the container under the bike, undo the bolts holding the filter on. Undo them a little at a time each. With most bikes now, the oil in the filter will have already drained out the bottom of the engine but there’s usually a little left and it will be hot and dirty as well. If your bike has a screw-on filter, undo it in an anti-clockwise direction using a filter wrench.
9. Remove the old filter and follow your owner’s manual’s instructions on fitting the new filter. It’s not a complicated process on most bikes and it should go in the same way the old one came out. Concentrate. Oh, and don’t forget to replace the old gaskets with the new ones. Filter retaining bolts tend to have quite low torque setting so don’t over-tighten them. If your bike has a screw-on filter, wet the rubber seal at the open end with new oil before screwing it back on in a clockwise direction. If you can get a firm grip on the filter, do it up as tightly as you can by hand. This is usually enough and you’ll thank yourself next time it has to be removed. If you’re nervous about it being tight enough, use the filter wrench to turn it just another 10 degrees.
10. Using a new washer, replace the sump plug and tighten it. If your manual doesn’t give you a torque setting (or you don’t have a torque wrench), tighten it until you feel the resistance of the new washer (you can’t tighten it any more by hand or light pressure from the socket) and then use the socket spanner to turn it another 45 to 90 degrees. Stop tightening it if the resistance is making it too difficult to turn. The new washer will compress in this process and stop oil from leaking.
11. Refill the engine with fresh oil to the required amount (around 1500ml on the Hyosung). Let it settle and then check the level using the sight glass or dip stick. Tighten the filler cap and then run the engine for three or four minutes before checking the level again and topping up if necessary.
12. Check the filter cap or screw-on and sump plug for any signs of leaking, and check them again after your next long ride.
Just a word about the environment
Our generation has lived in the wonderful world of the internal combustion engine. We’ve seen the best of its development and I personally don’t think I’ll ever be able to love the alternatives as much as I do the rawness and excitement of two strokes and four strokes. This, however, has come at a cost. Of the worldwide use of oil, 55 per cent of it is for transport. In the US, the figure is 70 per cent. Wars have been and still are being fought over access to oil supplies. Our humble oil change is a tiny part of a very big picture.
I’ve advised you to wear gloves during the oil change as used oil is toxic. Penrite says one litre of oil will pollute one million litres of water, which is why you have to dispose of your used oil responsibly. It’s illegal to put used engine oil in your weekly garbage or pour it down the gutter drain outside your house.
The glimmer of good news is that used oil can be used again as bunker fuel, recycled as industrial fuel and even be re-refined. Your local council will have a recycling depot and a simple call to them will give you the information you need to minimise your oil-use footprint. You can get further information from www.oilrecycling.gov.au
Frequently asked questions
- Can I mix mineral oil and synthetic oil if I’m stuck out in the bush and can’t get the oil that’s already in the bike? Yes. It won’t do any harm (and it’s certainly preferable to running an engine without enough oil) but the best option is to try to be consistent with the type of oil you use.
- Why are oils different colours? Sometimes it’s just a branding statement but oil usually becomes progressively darker in use as it picks up contaminants. If the inside of your bike’s engine is clean, the oil in the sight glass should be light brown or goldish. If it’s dark or black, it’s an indication of time for a change.
- Will my bike’s clutch always slip if I use an oil with friction modifiers in it? No – many riders use car oils because they’re cheap and available and never experience any adverse affects but it’s hard to see why you’d take the risk.
- What’s “peak oil” and should I be scared of it? Peak oil is the point in time when the maximum rate of petroleum extraction is reached. Many commentators believe we’re already past it. We’ll probably go through a phase of oil depletion – falling reserves and supply – before a better (but probably less exciting) source of power starts dominating.
- Can I have the mobile number of the girl at the beginning of this story? No.