The focus on four-stroke oil: This is what you need to know!
The lifeblood of a four-stroke engine is motor oil. The oil in your four-stroke motorcycle has several important functions such as lubricating, cooling, cleaning, sealing, dampening noise and preventing corrosion. Most four-strokes, except Honda CRF models up to and including 2016, use the same engine oil to lubricate the valves, cams, piston, crankshaft, clutch and transmission. The oil in your four-stroke lubricates more than twice the moving parts than the premix and gear oil of a two-stroke.
In an effort to reduce weight and increase power, your lightweight four-stroke motocross bike uses just enough oil to get the job done. In a dirt bike, it is more important than ever to use the best racing oil and replace it routinely. Engine specific oils are equipped with five times more anti-wear and extreme pressure additives than regular engine oil. As an added plus, the oil is free of molybdenum disulfide and other friction modifiers that degrade clutch performance.
Which oil do I use in my dirt bike?
If the bottle of oil does not state that it is an API SG service category or JASO MA specification, it is not good enough for your dirt bike. Although a bottle of oil may state that the product is "safe for wet couplings," the best approval is the API SG or JASO MA designation. This designation dates from a few years ago, which means that "higher" types are currently common. However, there is an exception for CRF owners, which we clarify below.
What viscosity?
The most popular viscosity is 10w40. It is thin enough not to put too much strain on the crankshaft and provides ultimate protection under extreme loads. But 5w40 and 10w50 are also options. Each owner's manual lists the recommended oils, brands and the correct viscosity.
You have a Honda CRF up to and including year 2016.
Do not use engine oil or gear oil in the automotive CRF transmission. If the transmission oil label does not have the words “two-stroke oil”, “safe for use in wet clutches” or the API SG or JASO MA designation, do not use it. Honda uses separate oil for the engine and transmission of the CRF up to and including year 2016. This is not a new idea. BSA did it decades ago. Yamaha, Kawasaki, KTM and Suzuki use the same oil in the engine and gearbox.
You have a Honda CRF from year 2017.
Honda changed the gun in 2017 and from that year on uses the same system as the other brands. This means that from then on Honda will not use separate oil systems on their CRF models and will therefore use the same oil for the lubrication of the engine and gearbox.
The difference.
Separate oil: The advantage of separating the oil, as with the Honda CRF, is that the top is not contaminated by clutch residue or metal filings from the gearbox. In addition, the heat from the combustion side does not dilute the transmission and clutch oil. The CRF can use an MA series oil in the transmission and MB series oil on the top end. The downside is that the amount of oil in each chamber is reduced (to about 650cc), requiring more frequent oil changes. Any oil loss, no matter how small, becomes critical when you are confronted with an oil leak.
Shared oil: The advantages of using the same oil in the engine, such as the RM-Z, KX-F, KTM and YZ-F, is that the large supply is less likely to reach critical values, the overall engine temperature is reduced and oil changes are needed less often. The downside is that split oil engines must use an MA series clutch oil (which means the engine around the combustion section doesn't get the benefits of the slick MB friction additives.
When to refresh?
Yamaha recommends changing the oil and oil filter every five rides. The Honda mechanics in the MXGP recommend changing the engine oil as often as possible and replacing the oil filter every time. One of the problems with a frequent service schedule is that it invites people to use cheaper oil. Don't get caught and always use quality oil! Naturally, you must adhere to the interval schedules prescribed by the manufacturer.
Look at your drain oil.
Pay close attention to the condition of the used oil. If it looks and smells dirty, you need to maintain it more often. Professional racing teams send their used oil to labs to have it analyzed. Labs use a spectrograph to determine which metal particles and other contaminants are in the oil. They can also read the engine's temperature management from the analysis. This is too expensive for a hobbyist, but it is best to pour the used oil through a sieve to detect any problems such as broken clutch plates, teeth of gears or other strange deviations.
How does an oil filter work?
Oil filters are necessary for four-stroke engines because the oil quickly becomes dirty. A dirt bike's oil filter is just like your car's oil filter. The system works as follows: a pump at the bottom of the engine sends oil to the filter. From there, the pump first distributes the oil to the combustion area. This is done so that the most important parts of the engine such as the camshaft, valves, main bearings and large bearings receive the cleanest oil. Afterwards, the oil ends up at the bottom of the crankcase and the process starts again.
The specifications.
The oil in your four-stroke motocross bike must at least meet the API SG or JASO MA standards. Your local motocross dealer now sells oil with a higher classification and you will mainly encounter the API SJ/SL and the JASO MA-2 standard. It goes without saying that it is an evolution of the API and JASO standard, so you can use this oil in your machine with complete confidence. In other words, you don't have to think about it in the shop. You can see how to change the oil in the two videos below. The first video applies to all brands, the second video is specific to Honda models up to and including year 2016 with a separate oil system.
Also to read
MXGP Lugo: live timing
This weekend the MXGP caravan arrived in the Spanish province of Galicia and more specifically in Lugo for the sixth confrontation of the year. You don't have to miss anything from the…Tomac will not be in action for the time being due to a thumb injury
This weekend, Eli Tomac will not be in action at the Monster Energy AMA Supercross Championship finals in Salt Lake City. During the race in… the Yamaha rider…An update on Camden McLellan's injury
South African Triumph factory rider Camden McLellan broke his fibula in Agueda and has to sit out a number of races. However, his start to the season went well and he was even able to ...Langenfelder is going to try it this weekend
Last weekend during the mud festival, Simon Langenfelder was injured. The GasGas rider crashed in the early stages of the second moto and broke his collarbone. The German is finished…
Your reactions