We all know that oil is the very lifeblood of our engines; it’s one of the most important components that keeps your machine purring like a kitten.
Knowing how important the oil is then, you won’t be surprised to find that riders can get a bit over eager with the frequency at which they change their oil out.
It is by no means a terrible thing to change it early, but here I am going to cover some aspects of today’s motorcycle oil that will hopefully show you that it can last longer than you might think and in turn save you a bit of money in the process, and I hope this will then answer the much asked question ‘how often should you change motorcycle oil?’.
Oil Breakdown – All oil will break down in time, and although there are many factors as to why oil breaks down, the main contributor is the heat that’s generated during the combustion process. When it’s subjected to enough heat, the oil will vaporise, this is known as an oils flashpoint.
Oil Contamination – There are three main ways in which our oil becomes contaminated, which are, the debris that gets through the air filter, the metal shavings/particles created as a result of metal to metal contact in the engine, and the by-products of the combustion process which raise the acidity of your oil, in turn causing internal corrosion as well as leaving deposits in the engine.
It all sounds pretty horrific, but before you rush off and change your motorcycle’s oil in a blind panic, first hear me out as to why there’s no need to fret.
Taking the above into account, you would be forgiven for thinking that any oil would struggle to deal with the onslaught that it has to deal with, but lubrication has come a long way since our dads first started riding motorcycles. The latest and greatest synthetic motorcycle oils (both semi and full) are designed in laboratories to a specification that will ensure it can deal with the strains it gets put under. Let’s look at how today’s motorcycle oils keep our engines safe.
Minimal Oil Breakdown – Older, cheaper petroleum based mineral oils start to break down almost immediately, not a trait that is shared with synthetic oils. This is because they have a much higher flash point over mineral oils, so they can withstand much higher temperatures, meaning breakdown rates are considerably lower.
In fact, a high quality synthetic motorcycle oil can last for thousands of miles (even on the track) before it will experience any sort of reduction in protection or performance characteristics, this is because they aren’t solely refined like mineral oils and are designed in labs with specific requirements in mind, so a higher tolerance to the conditions in the engine is practically built into the oil.
Dealing with contamination – In truth, the best way to reduce oil contamination is to stop the worst of the contaminants from entering the engine in the first place, that’s where your air filter comes in. A good quality air filter will do a good job of catching those nasty dirt particles before they’re able to make it into the engine.
That’s already the first of the major contaminants nipped in the bud, but as hinted to above, the other two main types of contamination come from inside the engine. So how do we prevent these contaminants from affecting our oil? The answer is we don’t. Our oil does.
Tiny metal particles make it into the oil because of the metal to metal contact that occurs during normal operation. With the petroleum based mineral oils of old, this was a more regular occurrence, particularly during starts up. Old oils would quite quickly drain back down to the bottom of the engine after use, meaning that when the time came to start it again there wasn’t a great deal of protection for the engine.
This isn’t the case with the synthetic oils of today though. What they’re actually designed to do is to leave a thin film of oil over the engine components so they are protected on start up.
What’s more, this thin film will generally remain on the components for days, even weeks at a time, the result of this coupled with their high quality lubrication characteristics means that theoretically your engine should never see pure metal to metal contact if used regularly.
The last contaminant that needs to be dealt with is combustion by-products. There’s only so much your oil can do to keep these nasty substances at bay, and what the oil really wants is for them to be dealt with by other components – the piston ring seals and the filtration system. Good tight ring seals mean that minimal by-products will make it into the oil, so there are less contaminants that the oil needs to deal with.
Synthetic oils do however do two things to help the situation. The first is to encourage tighter ring seals (this is because of the very construction of the oil), the second is an ability to neutralise these acidic combustion by-products and stop them from doing any damage to the engine. With the ring seals and oil working together you can be sure that this last type of contaminant will be kept to a minimum.
As good as the air filters, ring seals and oil itself are at keeping contamination levels down, there will undoubtedly be an amount of debris of some sort in the oil that needs to be dealt with, and even though the additives in the oil do a good job of holding the debris in suspension and impede contact with engine’s components, they still need to be removed, and that’s where the filtration system comes in.
Your oil filter will catch the majority of left over contaminants once they flow through it, permanently neutralising them and preventing them from re-entering the oil flow and going back around the engine.
Choosing good quality filters – It would take many more pages to actually explain the different grades of oil filter and how they work, but I think the best piece of information I can give you is that the engine manufacturer would have taken particles in suspension into account when specifying the filter for your bike, so I will simply say use OEM filters and you won’t be too far from the best possible filtration system for your bike, which means you’ll stand the best chance of keeping those horrible contaminants at bay.
Quite simply, according to your service manual. It should be clear now that today’s oil and filtration systems have been specifically designed and manufactured to keep your engine as lubricated and protected as possible, and knowing that the engine manufacturer would have taken into account particles in suspension when specifying the filter, as well as oil degradation due to engine wear and the combustion process, it’s safe to say that your engine will be protected right up until the time specified in your manual.
This is assuming you are using high quality oil and filters. Like most things, you get what you pay for and oil is no different. High quality oils will have all the right attributes to ensure your engine is efficiently lubricated and protected. Just like tyres, if you buy cheap, they don’t perform as well or last as long, so stick to good quality oil and filters for the best protection.
No, of course not. I’m not here to tell anyone they’re silly for changing it early, merely to demonstrate that oil and filters have come on a long way from 50 years ago, and these new fancy laboratory made oils are up to the task of keeping our engines safe.
However, in the grand scheme of things oil and filters aren’t a massive expense, so if you’re happy to change them early for piece of mind then there’s nothing wrong with that. Without getting the oil tested we can never really know the true state of our oil through its different stages of use, so taking a precautionary stance is by no means a terrible thing.
Also if you have a highly tuned engine, I would actually encourage changing it early due to the higher running speeds and temperatures generated as a result.
While this article is a little less technical than it could be, the result of going into every aspect in fine detail would have made this article 40 pages longer, however I would like to think I have done enough to show you that our engines are in safe hands with the latest high quality synthetic oils and that dropping your oil after every 1-2 track days isn’t really necessary.
So if your wondering how often to change your motorcycle oil, I will say that you can quite easily change it according to your schedule if you wish (I do), but if you want to leave yourself a margin, you’re not doing any harm. Just make sure you are happy with your oil change intervals, as that’s all that really matters.
Photo by Claude Fabry
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