A Guide to Dirt Bike Oils: 2-Stroke & 4-Stroke

Figuring out the right oil to use for optimum performance of your dirt bike need not be difficult.

Just like a car, different engines from different manufacturers use different oil. The key in finding the right oil is two-fold. First, do you ride a 2-stroke or 4-stroke dirt bike? There is a big difference here not only in oil but in what you do with the oil. (Check out our 2-Stroke and 4-Stroke exhaust guides.)

Two-stroke oil is used in crankcase compression two-stroke engines. The four-stroke engine utilizes a closed crankcase. The crankcase in the two-stroke engine is used as part of the induction tract. Therefore, in a two-stroke engine you mix your two-stroke oil with gasoline - the gasoline acting as lubrication throughout the engine.

Two-stroke oil is a bit different than 4-stroke oil in that 2-stroke engine oil does not have weight indications. Additionally, two main types of 2-stroke oil exist: injector safe and pre-mix. Most dirt bikes fall into the pre-mix category that is combined with gas.

Four-stroke oil is more like the oil used in cars but both 2-stroke and 4-stroke oil serve the same purpose - to keep the engine lubricated. Four-stroke dirt bike oil comes in a variety of weights like 10w-40, 20w-50 and so on. It is not mixed with gas.

So now what oil should you use? Easy. The second key to finding the right oil for your dirt bike is: Read your owner's manual to find what oil the manufacturer recommends for your bike.

If your manufacturer recommends 20w-50 for your 4-stroke then don't buy 10w-30 weight oil. The most common weight for dirt bikes is 10w-40. Your owner's manual also explains what ratio to mix your oil and gas for the 2-stroke engine in order to get the best performance. It can be anywhere from 1:100 to 1:8 and all in between.

Always check your owner's manual for the correct weight in oil that works best with your dirt bike. Once you know what weight oil to use, then we can recommend specific brands of oil in the manufacturer's suggested weight for your machine. We carry all the different oils your dirt bike requires to run smoothly and run efficiently without breaking down.

If you're running a 2-stroke make it easy on yourself and get a measuring cup device so you can accurately measure the oil-to-gas ratio recommended by the bike's manufacturer. Here are some recommendations for measuring cups.

Good Measuring Cup	Better Measuring Cup	Best Measuring Cup
BikeMaster Measuring Cup With Lid	Maxima Quick 2 Mix	Ratio Rite Measuring Cup
Price: $4.64	Price: $5.39	Price: $5.99
Features: More stable than the older designs when filled with oil Ratios from 8:1 all the way to 70:1 Shows as percentage of mix graduations in gallons, fluid ounces, liters and milliliters on it	Features: Accurately mix in ratios of 24:1 to 100:1 Convenient cap keeps inside clean Mixes ounces, CCs, gallons and liters Durable polypropylene	Features: Raised measurement marks Simple and convenient Easy to find the correct ratio

Now for the oil.

2-stroke Oil Recommendations

Good 2-Stroke Oil	Better 2-Stroke Oil	Best 2-Stroke Oil
Pro Honda GN2 2-Stroke Injection/Premix Oil	Bel-Ray H1R Synthetic 2-Stroke Oil	Maxima Castor 927 2-Stroke Oil - 64oz
Price: $6.64	Price: $8.99 - $20.99	Price: $9.99 - $31.99
Features: Tested and approved by Honda R&D Clean-burning formula reduces exhaust smoke, carbon buildup and varnish deposits helps prevent spark-plug fouling, ring sticking and exhaust plugging extends service life for piston rings and bearings	Features: Advanced 100% synthetic ester base oils cling to metal Clean burning to prevent carbon build-up Improved power and throttle response Anti-wear chemistry	Features: Reduces carbon and gum formation Exclusive additive that keeps power valves cleaner and working properly Biodegradable Extra protection on cylinder walls, bearing journals

4-stroke Oil Recommendations

Good 4-Stroke Oil	Better 4-Stroke Oil	Best 4-Stroke Oil
Yamalube 10W-40 All Purpose Oil - 1 Gallon	Pro Honda HP4M 4-Stroke Oil With Moly	Motul E-Tech 100 Synthetic Oil
Price: $5.08 - $18.68	Price: $8.98	Price: $13.99
Features: Ultra-clean additives High-quality general use oil Excellent protection and technologically superior additives Provides stable clutch performance and film strength	Features: Provides high thermal stability Eliminates oil consumption Ensures total cleanliness of engine parts Provides good friction on clutch discs	Features: Designed to work with performance engines, wet clutches, gear boxes, internal chains, high lift cams and heavy loads Combination of proprietary Esters and Polyalpaolifine (Pad) synthetic base stocks High performance and city stop and go applications

Dirt Bike Gear Oil

If you've perused the aisles of an auto parts store or scanned our Dirt Bike Oils, Fluids & Lubrication page you may notice some oil with a viscosity weight of something like 80w-85. You'd never put that in your engine but it's exactly what you'll use in your transmission. Gear oil or transmission oil requires a higher viscosity to protect those vital parts from break-down and to cool off your clutch. A word to the wise: Don't use car transmission oil - it causes clutch failure in your dirt bike.

Again, the best gear oil for your dirt bike is found in the owner's manual.

Gear Oil Recommendations

Good Gear Oil	Better Gear Oil	Best Gear Oil
Pro Honda HP Transmission Oil - 80W/85W	Maxima Hypoid Gear Oil	Silkolene Comp Gear Oil
Price: $7.11	Price: $9.99	Price: $16.99
Features: Works on any motorcycle Offers an ultra-high film strength and shear stability to minimize transmission wear Formulated with special anti-friction additives Anti-shear additives increase clutch life and reduce clutch slippage	Features: Special high shear strength polymers Provides long lasting protection Petroleum blend for high performance shaft driven motorcycle	Features: Semi-synthetic ester-technology-based Developed primarily for competition / racing off-road motorcycles Formulated for use with aluminum or steel clutch plates Reduced oil contamination

Dirt Bike Air Filter Oil

For those new to the world of dirt bikes adding oil to your air filter may be a head-scratcher. You don't use regular engine oil for your air filter (though in a pinch you can with mixed results) instead you use air filter oil. A coat of air filter oil applied to your air filter, which is then allowed to dry, traps more dirt, debris and other engine damaging contaminants than without it.

Air filter oil serves to preserve the life of your engine by keeping the engine oil cleaner. You may also save money in the long run by needing less frequent oil changes. Air filter oil is something typically not a recommendation by the manufacturer in the owner's manual so we can definitely weigh in on as far as which air filter oil historically produces the best results.

Air Filter Oil Recommendations

Good Air Filter Oil	Better Air Filter Oil	Best Air Filter Oil
Honda Air Filter Oil (No-Toil) - 16oz	Maxima FFT Air Filter Oil	Bel-Ray Foam Filter Oil
Price: $8.37	Price: $7.49 - $11.99	Price: $8.99 - $12.99
Features: Biodegradable Super-tacky Traps more dirt and allows more air than conventional air-filter oils Eliminates need for toxic chemicals	Features: Synthetic polymer formulation 4 - 12 percent more air 8 percent more contaminants Resists both water and gasoline "fogging" wash out	Features: Fast drying Ultra-viscous Waterproof Easy application

Remember to always consult with the owner's manual for your dirt bike to determine the best oil for optimum performance and durability. Some owners never sway from a specific brand but they use the weight recommended by the manufacturer.

Semi-synthetic and full synthetic oils protect today's modern engines that run harder. Synthenic oils are cleaner and last longer then conventional petroleum based oil. Newer engines may require only the use of semi-synthetic or full synthetic oil, again, your owner's manual provides direction on this.

For older engines synthetic oils work, however, engines fed on a 100 percent diet of petroleum-based oil for the last 15 years, you may start to see oil leaks after using synthetic oil. This occurs when the synthetic oil cleans the sludge off the engine seals thus exposing cracks in the seals.