Modern motorcycles use detergent oils in them. However, there are always some old bike riders who rattle on about non-detergent oils and claiming how terrible detergent oils are for the engine.
So, which is better for motorcycle – detergent oil or non-detergent oil? Detergent oils provide better performance since the detergent additives prevent any deposit formation in the engine components. The contaminants float in the oil and will be removed by the oil filter.
Non-detergent oils, however, gather contaminants and allow sludge formation which can cause problems.
What differentiates detergent and non-detergent oil?
Engine oils will always have additives added to their base stock. Base stock or Base oil are the primary constituent of the engine oil borne from petroleum or chemical processing. Base stock usually forms the 80% to 90% of the engine oil.
Additives are the chemical compounds added to the base stock to improve performance of the engine oil. Additives constitute around 10% to 20% of the engine oil.
Additives include detergents, corrosion inhibitors, antiwear additives, alkalies, friction modifiers, foam inhibitors etc. These are not only used in engine oils. There are additives in gasoline, in fork oil, shock oil and whetever any other automotive oil you can think of.
Detergent additives are the one that differentiates between a detergent oil and a non-detergent oil. If the engine or motor oil contains detergent additives in it, it is called a detergent oil. If there are no detergent additives added, then the oil is called as non-detergent oil.
Detergents or Dispersants are used to clean and neutralize the impurities in the oil which normally would have caused deposits or sludge on the engine components.
Detergents ensure that these impurities and foreign objects stay in suspension to allow the filtration system to remove these impurities. As a result they are used widely in many oils, not just engine oil. Even gasoline has detergents added in them.
With these functions, detergent additives play an important role in the performance of motor or engine oils. A non-detergent oil, which does not contain any detergents, will not feature these functionalities in them.
Detergent oils use detergent additives in them. Hence the name, detergent oils. What these detergents do is – they clean and neutralize the impurities in the oil which normally would have caused deposits or sludge on the engine components.
The detergents essentially perform two main roles.
First, the detergent additives keep the engine and other lubricating metal components clean and free of any deposits.
Second, detergents neutralise the formation of acids in the engine oil. Detergents are primarily alkaline in nature. Any acids formed within the oil due to contamination and the heat, is neutralised by these detergent additives.
Detergents ensure that these impurities and foreign objects stay in suspension to allow the filtration system to remove these impurities.
This functional aspect of the detergents makes detergent additives more attractive to be used in the modern motorcycles. Most modern bikes use detergent oils and the engines perform much better with detergent oils.
In earlier times and old motorcycles, non-detergent oils were the only option available to be used for the engine lubrication.
In addition, in these motorcycles, oil filters were mostly seen as an option and not as an industry standard. As a result, non-detergent oil acted as the magnet for contaminants in the oil.
This prevented the contaminants from depositing on the sidewalls of the metal components.
Overtime, all the contaminants gather in the non-detergent oil to form sludge. The oil should be changed completely with a fresh oil to remove the sludge from the motorcycle. Here, toping up the oil does not work suitable since the contaminants still exist in the oil.
This results in a shorter time interval between the oil changes. A non-detergent oil should be replaced with a fresh one much more frequently when compared with a detergent oil.
Comparison between the oils
Now that we have discussed what these oils contains and what is their differentiating factor, i.e., detergent additives, let us compare these two oil types on their performance, oil change, and what they are best suited for.
When it comes to performance, detergent oils are much better since the detergents in these oils will keep the engine and other lubricating metal components clean and free of any deposits.
In addition, detergent oils will also prevent formation of acids in them. Detergent oils ensure that the impurities, contaminants and foreign objects stay in suspension to allow the filtration system to remove these impurities.
Non-detergent oils, on the other hand, gather the contaminants and impurities and form sludge.
The handling of contaminants is much more efficient in the detergent oils when compared to their non-detergent oil counterpart. In addition, detergent oils do not allow formation of acids in them.
So, clearly, detergent oils fare much better in terms of performance here. Since modern motorcycles come with a robust oil filter, the contaminants in the oil will be easily filtered. Non-detergent oils, however, will allow sludge formation.
Oil Changing Frequency
Since non-detergent oil gather all the impurities, contaminants and foreign objects and allow formation of sludges, the oil needs to be replaced with a fresh one regularly.
On the other hand, detergent oils, does not have the formation of sludges easily. Hence, the oil changing frequency will be much lesser than that of non-detergent oils.
That’s why, the changing interval for non-detergent oil is much lower than the detergent oil. Non-detergent oils should be changed and replaced with a fresh one much frequent and at much faster intervals.
Detergent oils can be replaced at a much slower rate and much lower frequency since they don’t allow sludge formation easily.
Best Suited For
Now, non-detergent oils are a thing of past and hence, are mostly suited for old and vintage motorcycles. Non-detergent oil will find its use specially in motorcycles that does not have oil filters in them.
If there are no oil filters to filter the contaminants, the next best thing is to gather these contaminants and impurities and form sludge. Then all we need to do is drain the sludge out of the motorcycle during oil change.
Hence, non-detergent oils are suitable for motorcycles with no robust oil filters, which can be seen in old motorcycles.
Detergent oils, on the other hand, are robust additives used in oils to keep the metal components free of deposits and suspend the contaminants which are filtered out. That’s why, detergent oils find their application in most modern motorcycles.
The motorcycles of the current times invariably prefer detergent oils due to their superior performance. Hence you can see wide usage of detergent oils in almost every modern bike.
Which Oil is better for Motorcycle?
As evident from our discussion in previous sections, detergent oils are far superior in terms of functionality and performance when compared to non-detergent oils.
Some bike riders, specially of vintage and old motorcycles, like to rattle on about what a great thing non-detergent oils were and how terrible modern detergent oils are. But this notion is absolutely baseless and has not valid merit.
Detergent oils, as mentioned earlier, have additive package designed to hold small particles of dirt in suspension until the oil filter can remove them.
And non-detergent oils do not have such additives. The dirt and contaminants that end up in the filter will actually get deposited throughout the engine forming sludges. This can eventually cause blocking of oil passages, impairing heat transfer, and creating many sorts of issues.
To put it simply, non-detergent oils have no place in a modern motorcycle engine. You will barely find a non-detergent oil on the shelf, outside of a lawnmower shop.