Most of us are very familiar with engine oil. We know that the engine oil level is on our regular maintenance checklist, and that engine oil needs to be changed come service time. But what about gearbox oil, or transmission oil?
The first point to note, is that gearbox oil is generally only used in 2 stroke engines. Because of the way in which a 2 stroke works, the oil required for the gearbox is of a significantly different make up than that of the head. Four stroke engine will normally only have one oil for both parts of the engine. There are a couple of 4 stroke engines that have separate oil chambers for head and transmission, the CRF450 and CRF250 for example. As with all critical components, check your bikes manual before making changes.
Gear oil is made with the sole intention to protect transmissions and transfer cases. The oils have a higher viscosity and other unique qualities that not only lubricate and cool but also keep your gearbox free from contaminates collecting on the hard surfaces inside. Dirt bike transmission oil protects against corrosion, rubbing, scoring, and pitting. Overall gearbox oil should result in smooth, quiet shifting, and a long-lasting gearbox.
General Oil tips for motocross bikes
Before changing your transmission oil, ascertain the correct type and quantity to use. Your bikes manual will give you this information. Gear box oil changes on dirt bikes are carried out after a certain amount of hours have been ridden.
- Always change your transmission after you have reached the hours ridden.
- Always wear protective gloves, and have plenty of rags ready to clean up any spills.
- Drain the transmission oil into a suitable container and dispose of properly.
- Fill your transmission using a funnel, to the correct level. Don’t forget to replace the filler cap!
Motocross Oil Frequently Asked Questions
How long does dirt bike oil last? Answer: Most good Dirt Bike oils lasts usually 5-6 hours. 3-5 hours for a two-stroke.
Can I use standard car oil? Answer: Absolutely not! This is very important. You need to use the correct oil for your machine as the viscosity and make up gear box oil are entirely different. Using car engine oil could well damage your gearbox as car engines do not operate at such high temperatures.
How much oil does a dirt bike need?: This will depend on the model you have. Always consult your manual.
Will putting to much oil in harm my engine? Answer: Yes, overfilling can be very harmful. It can put too much pressure on seals and other components leading to failure.
Best 2-stroke gearbox oils available
1. Honda Transmission Oil
Honda lovers will be pleased to see this HP transmission oil on our recommendation list. It should also come as no surprise that Honda branded oil should be your go-to dirt bike transmission oil if you ride a Honda dirt bike. Honda oil will work great on any motorcycle.
The HP transmission oil is designed to have shear stability and extremely high film strength. Together these qualities help to reduce wear inside your gearbox. During intense use, gearboxes like any moving parts, get hot. The HP oil has been created for thermal stability meaning that the viscosity of the oil should stay consistent as the conditions in your gearbox intensify. This oil technology will also slow the breakdown of the oil making for a much longer lasting, non foaming product.
HP oil does its job incredibly well when shifting, even under heavy engine load, through minimizing the effects of drag between gears. Special additives in the oil further lower the friction of moving parts. All in all, this means smooth shifting and consistent performance. No one needs a missed gear on that critical last lap!
Further additives have been included with anti-sheer properties to increase the life of your clutch and stop it from slipping.
- Honda OE
- Stable in every riding condition
- Attains extremely low friction between moving parts
- Helps ensure a long clutch life
2. Maxima 80W90 Premium Gearbox Oil
Maxima’s premium gear oil nears perfection as with most of their other oils. This petroleum blend gear oil is specifically for high-performance shaft-driven motorcycles but works very well in all motorcycles that have separate areas for transmission or clutch fluid. It is even suitable for use with hypoid gear applications. Hypoid gears are spiral bevel gears where the axis does not intersect with the other axis of the meshing gear.
Inside the unique formula is high shear strength polymers which prevent the oil from breaking down. Ultimately the design leaves you with a long-lasting oil that protects your transmission from wear and tear.
Must be sourced outside of the UK.
- Designed for high-performance bikes
- Tough oil that does not break down quickly
- Good for use in any motorcycle application with a separate transmission fluid
3. Silkolene Comp Gearbox Oil
Comp Gear Oil by Silkolene is the real deal when it comes to off-road performance gearbox oil. Comp Gear Oil is an ester-based racing oil that is semi-synthetic and ready to tackle anything the serious motocross rider can throw at it.
Silkolene oil is developed to work well with both aluminium and steel clutch plates making it a great choice. Expect smooth gear changes and outstanding clutch action.
Gear drag is reduced by the low friction formula, which ensures a low wearing gearbox and less power loss through shifts.
This 2-stroke gear oil makes use of Silkolene’s Electrosynte Power Technology. Silkolens formula causes friction molecules to attach to high stressed metal components. During a race, when you are pushing hard, the oil bonds to highly stressed components. Ensure your gearbox stays consistent and in excellent shape with Silkolene.
Available in the UK.
- Silkolene’s Electrosynte Power Technology
- Low friction between moving components
- Long-lasting oil
- Designed for off-road racing
4. Bel-Ray Gear Saver Transmission Oil
Gear Saver by Bel-Ray is a high-quality two-stroke gear oil that ensures your transmission works as efficiently as it can.
Gear Saver has been manufactured specifically for motorcycles that make use of wet clutches. It provides superior clutch engagement which could equate to better starts for you out on the track.
The formula makes up a free-flowing, high viscosity oil that fully coats the inside of your gearbox to assure everything is well lubricated. Gear Saver oil gives silky-smooth shifts by keeping gear friction low. It also helps prevent clutch and gear rub leading to a long-lasting, and quiet transmission.
Available in the UK.
- Positive clutch engagement
- Coats gears fully to prevent wear and encourage long life.
Now we are all covered with the transmission oils. Next make sure that you know how to maintain your air filter and you clean it with the best possible air filter oil!