Dirt Bike Oil – Get the right oil for the right bike!

dirt bike oil infographic

There are so many different types of dirt bike oil!

Like any machine, a dirt bike needs lubicration to last.  Fluids need to be changed regularly as part of your maintenance schedule, but there are so many different types of oils on the market.  How do you know you are getting the right kind?

Today we are going to look at the different types of dirt bike oils and what you should be looking for when you ultimately buy.

Any time you get a new or used dirt bike, changing the oils should be a top priority.  If it is a used dirt bike, you need to change the oils immediately, regardless of when the seller tells you they were last changed.  If it is a brand new dirt bike, ask the dealer what the typical break in period is and change them promptly after that has arrived.

Each manufacturer will generally have their own brand of oil for a particular category.  Whether or not you use their brand of oil is far less important than replacing the oil on a regular basis.  For instance, if your bike calls for Yamalube and you can find it, great, but don’t put off changing the oil until you find Yamalube.  Just change it with another oil that is the same weight and viscosity.

So lets take a look at some of the different types of oils that are out there.

Types of Dirt Bike Oil

dirt bike oil

On a dirt bike there are a ton of moving parts that need to be properly lubricated.  Some types of oils are going to be required on every dirt bike regardless of the type of engine, and others will be specific to the type of dirt bike you have (either 2 stroke or 4 stroke).

Oils that are on every dirt bike:

  • Air Filter Oil
  • Fork Oil

Oil just for 4 strokes:

  • Engine oil

Oil just for 2 strokes:

  • Gear oil or transmission oil
  • 2 stoke mix oil for the fuel

Dirt Bike Oil for your 4 Stroke

dirt bike oil 4 stroke

A 4 stroke engine has oil in the crank case that serves to lubricate the crank, the piston walls, AND the transmission.  In some cases you may find that your specific dirt bike has a separate area for both oil and transmission oil.  In that case you will need to change both.  However, for the most part, a 4 stroke dirt bike is going to use the motor oil to lubricate the transmission and the engine.

In general the weight of dirt bike oil is going to be 10W40.

How is Motorcycle Oil Different from Car Oil?

Oil that is specific for a dirt bike or motorcycle will have additives to it that make it safe to use with a wet clutch.  Since dirt bikes have a wet clutch, this is something that you need.  Often times they are formulated with a portion of mineral oil to be used safely with the wet clutch system.

What are some good 4 stroke dirt bike oil?

YamaLube and Maxima are a couple of great brands for 4 stroke oil.  Additionally, if you are in a jam and need some quickly, you can usually find motorcycle oil at your local auto parts store (think AutoZone, Advanced Auto, O’Reilly, Napa, etc).  They generally keep it in stock, but it might be located with the small engine parts.

If you are planning ahead and plan to order online, take a look at some of these options:

  • Maxima
  • YamaLube
  • Motul
  • Castrol

How much oil do I need?

A normal oil change is going to vary based on the type of dirt bike that you have.  Somewhere in the range of 1 quart per oil change is about right.  I typically change the oil filter every other time that I change the oil.  Since the oil filter soaks up some oil, I use 0.9 quarts on a normal oil swap and 1.1 quarts when I am changing the filter.  Your owners manual will have all of this information laid out for you.

Dirt Bike Oil For Your 2 Stroke

dirt bike oil 2 stroke

2 Stroke Engine Oil

For a two stroke you must mix oil in the gas in order for the engine to get lubricated.  Unlike a 4 stroke where the crank shaft is sitting in an oil bath, a 2 stroke crank is relatively dry, with the lubrication coming in the form of atomized oil/fuel mix coating the parts.  

You can’t just use normal motor oil to mix in with your fuel, you need to get 2 stroke (sometimes called 2 cycle) oil.

In a jam you can get this at most auto parts stores, and lots of gas stations will carry it as well.  This needs to be mixed into your fuel at the correct ratio.

Some 2 stroke oil is marketed as smokeless.  I haven’t found any of them to be truly smokeless, so don’t be disappointed if your 2 stroke oil still makes your 2 stroke smoke!

Take a look at a few of these options.  A gallon will last you a very long time.

  • Lucas
  • Amsoil
  • Maxima
  • Bel-Ray

2 Stroke Gear Oil

Since a 2 stroke engine doesn’t have an oil reservour, something has to keep your transmission and clutch in an oil bath.  This is handled with your gear oil.  Gear oil is a very heavy weight oil (in the 80W-90 weight range) with additives to it to make it useful for wet clutch systems.  Generally, most 2 strokes will have a sight glass on the bottom end of the motor that allows you to see the level of oil in the bottom end.

I have listed some good options for gear oil below.

  • Maxima Gear Oil
  • Bel-Ray Gear Saver
  • Lucas Oil Transmission Oil

Oil for All Dirt Bikes

There are a couple of types of oil that you are going to find on every dirt bike.  They are air filter oil and fork tube oil.  Since those aren’t common types of oils for cars, I feel like they are the least thought about.  As a result, they are also the least changed oil (although they should not be).

Fork Oil

dirt bike fork oil

The front forks of your dirt bike are more than likely filled with oil (unless you have a KTM or something with air forks).  Changing the oil in the front forks can be a daunting task when you first look at it, but in reality is not too bad. 

The main thing that you are going to need to know is how much oil to put in the front forks.  Most of the time this is either given in ounces or milimeters.  If it is measured in millimeters you will need to slowly fill the forks up until the level is the prescribed number of millimeters below the top of the fork tube.

So, this will seem like a lot the first time you do it.  After you do it though, you will look back on it and say it was not that bad.  The actual process for doing this varies based on the type of forks that you have. 

There are tons of great YouTube videos out there that can walk you through step by step on replacing the oil.  Look under “rebuild” videos. Watch them to get the basic steps for draining and refilling the oil, without going through the entire rebuild process.

Here are some fork oils that I recommend.  You need to make sure that you have the correct weight for your bike (5W, 10W, etc).  You should change your fork oil at least once a season.

  • Maxima 5WT
  • Maxima 10WT
  • Bel-Ray Fork Oil 10WT
  • Ravenol Fork Oil
  • Lucas Oil

If you are going to change the oil and need to get it to the millimeter depth, I also recommend getting this tool which allows you to fill the fork tube then draw out the oil until it reaches the exact depth.  For my suspension setup this is 100mm.  Motion Pro Fork Oil Level Tube.

Air Filter Oil

Most dirt bikes are going to use an oiled air filter.  The oil in the foam helps remove the particles from the air.  Take note of this: a dry foam air filter will not filter as well as an oiled one.  Foam filters are designed to be run with oil, so make sure you oil them.

Foam Filters can be cleaned and reused.  They should be replaced often, but since you can clean and reuse them, replacing them is not a huge financial burden.  The only time you will really need to buy a new filter is when the filter has holes or cracks in the foam.

Here are a couple of options for air filter oil.

  • K&N Air Filter Oil
  • UNI Foam Filter Oil
  • Maxima Air Filter Oil
  • PJ1 Foam Filter Care Kit

Wrap Up

There is a lot to keeping up with a dirt bike.  But, if you are able to use the correct fluids following the correct maintenance schedule you will help make your dirt bike have a long, reliable life.  Never, ever, run an engine without the appropriate lubricants, otherwise it will quickly die.  Hopefully you have learned the different kinds of oils and when to use them.  Stay safe out there!

Additional Reading

5 Dirt Bike Maintenance Items