Motorcycle engine oil does a different job from car oil. On most motorcycles the same oil lubricates the engine, the gearbox and the oil-bath clutch. That is why the wrong oil does not just shorten engine life; it can also cause problems such as clutch slip and harsh gear changes. In this guide we explain how to read the codes on the oil bottle, how to choose the right oil for your bike and how to decide when to change it.
The first rule: the owner's manual
Three pieces of information about the right oil are written in your bike's manual: viscosity (for example 10W-40), performance class (for example JASO MA2, API SL) and quantity (in litres, separately for changes with and without a filter). Everything in this guide is meant to help you read the values in the manual correctly. If the manual and a recommendation at the shop contradict each other, follow the manual.
Viscosity: what does 10W-40 mean?
Viscosity shows how fluid the oil is. In a code such as 10W-40:
- 10W: fluidity at a cold start. W stands for "winter". The smaller the number, the more easily the oil flows when cold. 5W is thinner than 10W when cold.
- 40: fluidity at the engine's operating temperature. The larger the number, the thicker the oil stays when hot and the thicker the oil film it forms.
10W-30, 10W-40, 10W-50, 15W-50 and 20W-50 are common values for motorcycles. The manual often gives a table by temperature range. In the colder inland regions of Turkey, a low W value makes cold starting easier; in very hot summer regions, a higher hot viscosity permitted by the manual may be preferred.
JASO classes: MA, MA2, MB
JASO T903 is the classification defined by the Japanese automotive standards organisation for four-stroke motorcycle oils. The main difference is to do with clutch friction.
| Class | Where is it used? | Feature |
|---|---|---|
| JASO MA | Motorcycles with an oil-bath clutch | Enough friction so that the clutch does not slip |
| JASO MA1 | A sub-class of MA | Lower friction range than MA2 |
| JASO MA2 | Modern engines with an oil-bath clutch | Higher friction range; low phosphorus and sulphur compatible with catalytic converters |
| JASO MB | Automatic scooters (dry clutch, CVT) | Low friction, aimed at fuel economy |
Important: if you use JASO MB or a car oil with friction-reducing additives in a manual-gearbox bike with an oil-bath clutch, the clutch may slip. If the manual recommends MB for your scooter, using MA2 generally causes no problem, but still check the manual.
API class
In the classification of the American Petroleum Institute (API), petrol engine oils start with "S": SG, SH, SJ, SL, SM, SN and so on. The further the second letter is along the alphabet, the newer the class. Motorcycle manuals usually give a lower limit such as "API SG and above" or "API SL and above". Note: some versions of the newest API classes designed for cars may contain friction-reducing additives for fuel economy; for this reason, on a motorcycle look for the JASO MA or MA2 marking as well as the API class.
Mineral, semi-synthetic, fully synthetic
- Mineral oil: refined from crude oil. Affordable and adequate for older, low-revving engines. Its heat resistance is lower than synthetics.
- Semi-synthetic: a blend of mineral and synthetic base oils. A good balance of price and performance; a common choice for daily use.
- Fully synthetic: protects the oil film better at high temperature and high revs, and flows better when cold. An advantage in high-performance engines and hot climates.
Synthetic oil does not give you permission to extend the change interval in the manual. The interval is set by the manufacturer; synthetic only provides better protection during that interval.
How often should it be changed?
As a general rule, oil and filter are changed on motorcycles every 5,000–6,000 km or once a year, whichever comes first. However, on some models the interval is shorter or longer; the exact value is in the manual. It makes sense to shorten the interval in these cases:
- Constant short-distance and city stop-start use
- Heavy and prolonged use such as courier work
- Riding in very hot weather and on dusty roads
- Bikes left standing for a long time (oil ages even when it is not used)
On a new bike the first change is done at the end of the running-in period; details are in the running-in guide. Change the oil filter at every change too, or at the interval in the manual; filter options are on the filter page.
How to check the oil level
- Run the engine for a few minutes, then switch it off and wait a few minutes for the oil to collect in the sump.
- Hold the bike upright on level ground: put it on the centre stand if there is one, otherwise ask someone to hold it upright. A reading taken on the side stand is wrong.
- On bikes with a sight glass, the level should be between the lower and upper marks. On bikes with a dipstick, measure according to the method in the manual (screwed in or not screwed in).
- If it is low, top up with the same oil and do not overfill. Too much oil also puts pressure on the seals and can cause foaming.
It is a good habit to check before a long trip and several times at fuel stops. If it is using oil or there is blue smoke from the exhaust, take it to a workshop.
Gearbox oil on a scooter
On automatic scooters, the final drive (gear case) next to the rear wheel mostly uses a separate, small quantity of gear oil. This oil is not changed as often as engine oil, but it should not be forgotten; the interval is in the manual.
Two-stroke engines
Some small scooters and off-road bikes use two-stroke engines. In these the oil burns mixed with the fuel, and a separate classification (for example JASO FD) is used for two-stroke engines. Do not use four-stroke oil in a two-stroke or the other way round.
Price ranges
According to our site's equipment data, motorcycle engine oil prices in Turkey range roughly from 374 to 2,275 ₺ at the economy level, 546 to 2,810 ₺ at the mid level and 810 to 3,156 ₺ at the premium level; the difference comes largely from pack size and oil type. Recommendations are on the engine oil page. To work out annual maintenance costs you can use the cost calculator.
If you are changing the oil yourself
An oil change is one of the easiest maintenance jobs that can be done at home with basic tools. Warm the engine up a little, put the bike upright on level ground and place a suitable container under the drain plug. After removing the plug, wait for the oil to drain completely, renew the plug's seal (washer) and tighten the plug to the torque in the manual; over-tightening can strip the threads of the sump. If you are changing the filter, smear a little clean oil on the new filter's seal and tighten it by hand. Fill the new oil a little under the quantity in the manual, run the engine briefly, switch it off, wait, and top up while checking the level.
Never pour waste oil on the ground or down the drain; collect it in a closed container and hand it in to a workshop or petrol station that accepts waste oil. Note down the date and the km of the change. Even if you always do your own maintenance, check in the warranty booklet how to document the servicing during the warranty period.
Conclusion
For the right oil, open the manual first: note the viscosity, the JASO and API class and the quantity. Use JASO MA or MA2 on a manual-gearbox bike, and whatever the manual says on an automatic scooter; stay away from car oil with friction-reducing additives. Track the change interval by time as well as km, and check the level with the bike upright.
Frequently asked questions
Can car oil be used in a motorcycle?
It is not recommended. Some car oils contain friction-reducing additives for fuel economy and can make an oil-bath clutch slip. Use motorcycle oil with the JASO MA or MA2 marking on the bottle.
Should I use 10W-40 or 10W-50?
Choose according to the viscosity and temperature range given in the manual. If the manual allows more than one option, a higher hot viscosity may be preferred in a hot climate and under heavy use.
What is the difference between JASO MA2 and MB?
MA2 is a high-friction oil for engines with an oil-bath clutch, while MB is a low-friction oil for automatic scooters with a dry clutch. MB should not be used in a manual-gearbox bike.
At how many km should motorcycle oil be changed?
Usually every 5,000–6,000 km or once a year, whichever comes first. The exact interval is in the model's owner's manual.