DIY! How to Tighten the Drain Bolt when Changing the Engine Oil!

How to

Many users enjoy practicing engine oil change because it makes the engine quieter, increases the torque, and makes a difference in the way the engine runs depending on the brand and viscosity. However, changing the engine oil can lead to unexpected mistakes if the work will be complicated as you get used to it. Are you tightening the drain bolt with a wrench from the beginning just because it is difficult to see underneath the engine?

There is no doubt if you choose the manufacturer's OEM engine oil!

The side cowl has a blue/silver 2-piece configuration to give a three-dimensional appearance. The silver wrap around the front of the engine cleverly covers the exhaust pipe, engine oil drain bolt, and oil filter.

Changing the engine oil is the most typical daily maintenance task that users can easily perform. The engine oil for a 4-stroke engine is the lifeblood for maintaining the engine condition, and regular replacement is essential for both small motorcycles and mega sports models such as lubricating pistons and transmissions, cooling the heat generated by combustion, sealing the compression pressure, etc.

Depending on the period of use and mileage, the time to change the engine oil when it undergoes oxidation or shearing within the engine varies depending on the model and operating conditions. Or perhaps it depends on the mindset of each owner. Changing expensive engine oil at short intervals is a blessing for the engine, but it can be a burden on your wallet. If you change inexpensive engine oil frequently, you'll get a good cosmetic result, but depending on the quality of the engine oil may affect the durability and wear of the engine itself.

The OEM engine oil with the motorcycle manufacturer's name on it is the safest and most reliable. OEM manufacturer's engine oil may seem like a "no-brainer, no-frills", but there shouldn't be a problem with the quality or performance of the engine oil you put on the manufacturer's crown. Naturally, the necessary abilities such as lubrication, cooling, and sealing are ensured, and on top of that, the strength of OEM engine oil is the durability based on rigorous tests and reasonable price.

When in doubt about which oil to choose, it is best to choose the OEM manufacturer's engine oil.


  • Engine oil requires to be changed regularly regardless of engine displacement and usage.
  • Performance and quality are guaranteed with OEM engine oil from motorcycle manufacturers

Changing engine oil every 5,000km of travel or every year

The side cowl is fixed with one upper and two lower hexagon socket head bolts, so remove the lower two first and then the upper. There is a possibility of stripping the hexagon socket head bolt if you use a wrench while the splashed gravel and dirt from riding in the rain are clogged in the hexagonal hole, so loosen the hexagon socket head bolt after removing the dirt.

The engine oil change for the 250cc class popular model, YAMAHA YZF-R25, is specified as 1 month or 1000km for the 1st time of changing the engine oil in a brand new motorcycle, 5000km for the 2nd time, and 5000km for the 3rd time or every year. The amount of engine oil required for this is 1.8 liters without oil filter replacement and 2.1 liters with oil filter replacement.

Whether you find this replacement period short or long depends on how you use the motorcycle. For riders who frequently go touring, the 5000km may be a bit too much. Conversely, a weekend rider who only rides a few times a month might have less than 5,000 miles per year.

Either way, you will need to change the engine oil when the time comes, but the number of DIY replacement has been increasing with the increased number of users who purchase parts and supplies online. Indeed, it is one of the simplest categories of the maintenance process because all you have to do is prepare a waste oil receiver, remove the engine drain bolt, and tighten the drain bolt when the old engine oil flows out and put in new engine oil.

However, adding overconfidence to a simple task may lead to unexpected problems.


  • Changing the engine oil can be done every year at its maximum even if the mileage is short.
  • Changing the engine oil is a simple task that requires discretion.

Visually check the drain bolt when draining the engine oil.

Remove the silver cowl to avoid damaging the joints between the cowls by sliding the claws off to be able to see the drain bolt underneath the engine clearly. While most drain bolts face downward at the bottom of the oil pan, the YZF-R25 has the drain bolt facing forward on the left side.

The drain bolt for draining the engine oil is mounted at the lower engine position to drained out the engine oil as much as possible (so as not to leave any old engine oil). Some models are tightened from directly behind the bottom of the engine, while others, like the sample model YZF-R25, face forward.

In either case, the most important is to "visually check exactly the location of the drain bolt". Depending on the working environment, you may want to avoid lying directly on the ground. However, if you groped for the bolt and applied force to the tool without making sure that the box end wrench or socket wrench was firmly seated on the head of the bolt, you could damage the hex of the bolt or the tool may come off, resulting in personal injury.

Removing the cowl makes it easier to work with either a box end wrench or a socket wrench, as it can be set from the right side. In the case of the R25, it would be better to take the cowl off without any hassle as you only have to remove the 3 hexagon socket bolts. When loosening the drain bolt from the left side of the motorcycle, use box end wrench or a socket that won't come off even if you pull hard, and don't use a spanner because you will have to pull the tool toward you.

The YZF-R25 has a side cowl where the drain bolt is hidden, and the drain bolt can be loosened if the tool is plunged into the back of the cowl even in this condition. However, if you take a few extra steps and remove this cowl beforehand, you can clearly grasp where the drain bolts are located and set easily with a socket wrench or a box end wrench to avoid any unnecessary accidents.

You can also know the timing when a bolt is about to come off by watching it while loosening, so you do not have to drop the bolt into the waste oil receiver.


  • Visually check the mounting position before loosening the drain bolt.
  • Sparing no "hassle" to improve accessibility to the bolts

Isn't bolt reluctant? Be sure to tighten the first few screw thread of the bolt with your fingertips

Once the old engine oil is drained, clean the drain bolt with parts cleaner, replace the old gasket, and tighten with your fingertips to the base of the bolt. Here's another reason why visual checking is so important. Even if the old gasket is sticking to the engine side, it can be detected by checking before tightening.

New gaskets prevent oil leaks by crushing itself after the bolts make contact with the oil pan. If you screw in the bolt with your fingertips and retighten with the tool from the point where it stops, you will feel the gasket crush, and see that there's no need to tighten it further when it's fully crushed.

The biggest advantage of being able to see the drain bolt during an engine oil change is when bolt tightening. Whatever the screw, the first 2-3 threads that hang on the other side when tightening are important. If you tighten the bolt with a tool while tilting, it will enter the mating female thread screw at an angle, causing the female thread screw to stripped as you tighten as it is.

It is important to tighten the bolt with your fingertips instead of a tool at first in order to avoid such mistakes. If you're using the force of your fingertips, you can feel that something abnormal has occurred when the bolt that entered diagonally stops moving.

However, if you use a tool such as a box end wrench or socket wrench that applies force away from the bolt, the torque applied to the bolt will be greater than if you carry it by hand, and you will not notice the tightness of the bolt since the torque applied to the bolts is larger than turning with your fingertips. You will be turned pale, saying "oh noh" when the bolt finally got in.

Since many models have an aluminum alloy engine side in combination with steel drain bolt, the female thread screw of the engine will be damaged, requiring tedious and costly repairs such as oil pan replacement and female thread screw regeneration.

Be sure to turn the drain bolt with your fingertips for a few piles of drain bolts, then set the tool and tighten it down to avoid such painful experience.

Before anything else, it is important to replace the drain bolt gasket with a new one before tightening and clean the bolt threads with parts cleaner.

If you do not replace the oil filter, the required amount of engine oil is 1.8 liters, so prepare two of 1-liter cans. The Yamalube Premium Synthetic of YAMAHA's OEM engine oil is a high-quality synthetic motorcycle oil blended specifically for motorcycles, which evaporates less even under high temperature and high load conditions such as a heavy traffic jam in the summer. The packaging has been redesigned from April 2019 and the image shows the old design product.

After putting in about 1.6 liters of engine oil, stand the motorcycle upright and check the oil level with the oil level gauge at the bottom of the engine. It is good as long as it fits between the upper and lower tick lines and does not necessary to fill to the upper limit. Let the engine idle for a couple of minutes and then recheck, and add engine if the oil level is lower than the lower limit.


  • Do not use tools at the beginning of tightening the drain bolt.
  • Turn the bolt with your fingertips and remove the bolt and check one if you feel stuck.

See YAMAHA Moto Index Page
See Accessories for YAMAHA YZF-R25 (R25)

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