Engine oil life?

My latest Intruder had covered less than 2000 miles in 2 years from new which set me thinking. How long can a modern oil be left in the engine, providing it is used regularly, but for very few miles? I know service schedules say 1 year but is this a ploy to generate dealer revenue or do oils genuinely 'go off'? I would hazard a guess that not much has happened to the state of the oil if left in place for 2 years. Anyone got any real tech info on this? Should sumps be emptied and refilled if a bike sits in a dealer's for 2 years, which is sometimes the case?

Hi John, does this help:

How Often to Change Motorcycle Oil

Key information to establish when we to change our oil

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?’.

Why we change our 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.

The latest technology keeps our engines safe

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.

The critical component – Filters

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.

So, how often should you change motorcycle oil?

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.

Does it matter if I change it early?

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.

Final words

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.

I onl use Silkolene ' full ester' anyway but I would rather see a bike use cheap oil changed regularily than an expensive oil not changed often enough. Oil is not expensive, not compared to an engine rebuild or replacement. I would have thought your oil would of been fine but I would change it myself.

Interesting info. I'm still not sure about 'shelf-life' of hardly used oil. HD service intervals are now mileage only and not time I believe. Suzuki are which ever comes sooner. Confusing or what?

If it's worrying you. Why not change it for peace of mind?

I was going to add, I personally change my oil and filter every year on a bike but Full Synthetic is not necessary unless its something like a Ducati or Fireblade. I always use decent Semi-Synthetic as recommended in the manual, but as the article says, todays oils are far better now, so I would have thought every two years would be fine on a low stressed engine that does not do mega miles, but I think short trips do more damage than long ones to the engine etc, I am guilty of only changing the oil in my wifes car every two years though.

Doesn't worry me Jeff, just curious of conflicting viewpoints. My Mount field mower has had the same oil in for many years - always starts first time and runs well! Spoke to Ducati salesman once. He said he had bikes in the corner with two year old oil - their service dept would say after the first year change it - nonsense he said! I will probably have mine changed on a date basis as usual. Does make you wonder though.

Hi John,
If you are out of the warranty period, and have good quality oil in the engine you can run to the 'mileage' rather than the 'time' interval with little if any detriment to the engine.
If you are within the warranty period you have to stick to their schedule are they have an excuse to void your warranty !
However, as others mention, with the relatively low cost of oil to 'if anything was to go wrong' then oil changes within the time frame offer better protection.
There is also of course the question of how you treat your engine. If one of my bikes hasn't been run for a while I always take the plug leads off and crank it over till the oil pressure light goes off to ensure fresh oil has circulated within the engine prior to starting it. I also the ride in a 'sympathetic' manner for at least 100 miles (i.e. Not dissimilar to running a motor in). I did that with the CBR6 that I'd owned from new & kept for 17 years but didn't ride it on a regular basis, & that motor remained 'sweet running' throughout my ownership.
I do use good quality oils and filters in all my bikes (& cars) & have never had any problems. My car is a diesel and it tells you when the oil has 'gone off' (i.e. if it becomes contaminated), or if the service interval is due. That gets done as per the cars inbuilt indicators - though I do keep a check on the service intervals (Which run out at approximately every 18000 miles - but car engines are less stressed than bikes - even so it needs 'special' oil to achieve the extended service intervals - something which I'm very careful about is ensuring the correct specification is met for my cars & bikes - This showed up on the first oil change I did on my mother's car, where I changed to the correct spec of oil & the car was quieter, ran smoother and returned slightly better fuel consumption ...... meaning the main dealer must have put the wrong oil in at the last service - It came as a second-hand car from main dealer !)
This is a topic everyone will have their own views upon - & I respect they may not align with mine. With the right approach you can work within mileage intervals, but even 'early changes' will not prevent damage cause by a lack of mechanical sympathy, or a careless owner - something the manufacturer has to consider when 'setting their rules'.
     Yam

Excellent read Andrew , I personally change my oil every year regardless of mileage but I only change the oil filter every other year, I've always used Silkolene Ride semi synthetic.
Very interesting topic, my mate insists on using mineral oil and I've tried to convince he's wrong but he wont have it, I'll print this off and see if he changes his mind.

semi Synth for me, usually at service intervals give or take 500 miles (I can feel a song coming on) pretty sure hd recommended 20w50 Mineral oil for the iron?.

I also change my filter every other time, however I don't leave my oil longer than I should.

Just curious, but why don't you change the filter with the oil, they are less than a tenner.

Agreed I always change both. Just my preference I'm not suggesting anyone is right or wrong in what has been said.

The manual says to change the filter every other oil change.

Lowey wrote:

Lowey wrote:

I'm not suggesting anyone is right or wrong in what has been said.

I'm not Jeff,  it's just people's different preferences I suppose? The service manual says every other oil change, so changing it at 3.5k is probably equivalent to changing the oil at 1750 miles.

I usually change oil & filter at the same time and usually a bit earlier than necessary even though I know there's no need to these days, it's just that if I know she's due a change I'd rather have it done and dusted and then it's one less thing to worry about.

I change both don't like putting clean oil in with a dirty filter but each to their own

I don't do a lot of miles so I do things my own way, which isn't far off recommended (I think). Oil once per year, filter once every second year. I always keep the chart on my garage wall updated, so I don't forget what has been done and when.

So it seems as clear as mud (or dirty oil  ) - change your oil and filter when you prefer!! Still not sure how long before oil goes off if not used much. My suspicion is that bikes are often over serviced particularly on low miles to tick the 'there, I've done it' box. So I'm now thinking the right interval is when you think it's right. Of course only the bike knows the real answer! My wife's car has less than 3000 miles on it and technically is ready for it's first service but the oil is pretty clean. Still, the car has a service package so it will get done regardless no doubt. Hey-ho!

It seems as if there is no definite answer to your question John, it appears we all have different views on it and each does what they are happy with. If you really wanted to get a definite answer you could connect one of the oil companies who might give you a more precise answer. All the best.

Bluesman wrote:

So it seems as clear as mud (or dirty oil   ) - change your oil and filter when you prefer!! Still not sure how long before oil goes off if not used much.

Apparently from what I've read today, (with my hectic workload) all the goodies (additives) in the oil break down over time due to oxidization, not so much a couple of years though, more like 5 or 6, the worst thing for oil is to be doing short trips and not getting the heat up, this causes condensation in the oil which also causes oxidization further braking down the goodies, I got bored then and decided it might just be easier to change the oil every year or so or every few thousand miles 

Cheers for that Sim. Most of us probably change oil as per schedule. I would imagine if you really push things, like not changing for 15k miles or 5 years, the bike would no doubt register its disapproval!

Sludge settling in the sump was another one of the problems of leaving dirty oil for a couple of years, I wonder how many bike shops change the oil as soon as they get them? probably none! especially as they usually sell them with a fresh service?, a more undesirable model could have been stood for 3 or 4 years with dirty oil?

simbo wrote:

Sludge settling in the sump was another one of the problems of leaving dirty oil for a couple of years, I wonder how many bike shops change the oil as soon as they get them? probably none! especially as they usually sell them with a fresh service?, a more undesirable model could have been stood for 3 or 4 years with dirty oil?

Yes, buying a bike with quite a few miles on it could hide any number of past horrors 

Bluesman wrote:

My wife's car has less than 3000 miles on it and technically is ready for it's first service but the oil is pretty clean. Still, the car has a service package so it will get done regardless no doubt. Hey-ho!

Her cars first service is an extremelly important one John, as with any vehicle car or bike.