10 points to consider if you change your motorcycle's oil: you shouldn't do it

You buy the oil, remove the old one from the engine, and pour in the new one. It's not difficult. What could go wrong? 

The truth is that you could even cause a serious breakdown.

We're not telling you this to scare you.  Our intention is to clear up doubts or problems that could arise. If you don't have experience, it's better to prevent mistakes that we've seen people make.

Many of them are just common sense. Others require you to know your bike a bit. But these mistakes do exist. 

We're going to tell you the 10 most important ones

1st Removing the transmission oil and refilling the engine oil

You may know that cars, unlike motorcycles,  keep the transmission oil separate from the engine oil. Well, no.

This fact has nothing to do with whether they're cars or motorcycles. It's true that almost all cars are like this and few motorcycles use this system, but there are some that do.

Off the top of my head, some Honda CRF cross models, the old Bultaco bikes used different oils in the transmission and the clutch. Also BMW Boxer,  which used transmission oil on one side, engine oil on another, and final drive oil at the end.

I've seen people remove the transmission oil and refill the engine oil, causing a double disaster. The transmission gets damaged from lack of lubrication and the engine from excess pressure.

2nd Tightening the filter with a wrench

It's not a serious mistake, but in the long run it's going to make your life harder.  Cartridge oil filters shouldn't be tightened with tools, only by hand.

We're referring to those standard ones that are "exposed," with their own metal housing, car style. Those shouldn't be tightened with the tool you use to remove the old one.

Once the old one is out, use your finger to moisten the rubber O-ring with used oil, put it on, and tighten it by hand as much as you can.

They tighten themselves with the engine's own vibrations. So, when you go to remove it, it's already very tight and you'll need tools.

If you tighten it with a wrench and overdo it, you could break its thread.  You could have a major oil leak if you don't notice, or you could simply break the filter.

3rd Be careful with the rest of the threads

Let me remind you that the crankcases you're working with are usually made of aluminum alloys.  They have relative hardness and many of the nuts, plugs, and bolts you're handling are made of steel.

That means if you tighten "as hard as you can", it's very likely you'll strip the block's threads.  You'll cause a serious breakdown that will need to be fixed.

This requires filling with weld and rebuilding the thread. Or repairing it, at the very least, with a "helicoil" or thread insert. Of course, it's not as perfect as the original thread.

By the way, always use washers like the original ones (copper, aluminum, or whatever it uses), preferably new ones.

4th Using any oil

No, car, tractor, or outboard oil won't work. You shouldn't even use scooter oil for a cross bike or vice versa.

Nowadays, oil technology is so sophisticated that they're formulated for a very specific use.  There are additives that help the clutch do its job without interfering with the valves in the cylinder head. Logically, these should be used in bikes where the engine and clutch lubrication are combined, for example.

There are  others specifically for engines that don't lubricate the transmission with that oil. Car oil (especially diesel) is formulated to work at a certain engine speed. It's not much like motorcycle oil and doesn't lubricate clutches or other parts that motorcycle oil does.

It can be even worse if you  refill with any oil, without knowing what's already in the crankcase. It doesn't usually happen nowadays, but in the past there were incompatible oils. When mixed, they degraded.

Still, in extreme cases with very different oils, it can happen.

5th Pouring it down the drain, in the field, or anywhere

This seems like common sense. It's outrageous to get rid of used oil any old way. We all know what needs to be done:  take it to a recycling center in a closed container.

You should also take any rags, oil filters, and trays you've used and want to throw away.

6th Filling above the level

There's a maximum level marked on the crankcase, the sight glass, or the dipstick. It doesn't mean "as long as it reaches here, it's fine", but "don't go past here."

Exceeding that limit means "drowning" the engine in oil and you could cause it to get into places it shouldn't. That's synonymous with stress for the engine and its different components.

In some cases, it could even get "whipped" by excessively touching moving parts.  This means it mixes with air and moisture in the crankcase, forming foam. It could even degrade and lose its lubricating ability.

7th Starting the engine to drain all the oil

I've known of someone who figured that, to get all the oil out, the best thing was to start the engine. The oil pump itself and the circuit's rotation would get all the oil out of every nook and cranny. It's not a good idea.

In a healthy engine, nothing will happen if you do it once for a few seconds. But it's not good for the pump to run out of oil, nor for many of the engine's critical points. 

During that time, it'll be "burning up" the contact surfaces that require oil. Also the oil film that may have stayed there.

Another thing is to warm up the engine and the oil itself by starting the bike for five minutes  before draining the oil. Thanks to its properties, when heated, it'll flow better and come out of the engine more easily.

Refilling with gasoline or diesel "to clean" is, in the end, another version of the previous bad idea.

8th Stretching oil changes too much

This is another one of those points that should be obvious. The oil must be changed every "x" kilometers (miles), and you shouldn't exceed that mileage.

In fact, keep in mind that, nowadays, both motorcycle and oil manufacturers show as an advantage that it lasts a long time. They already tend to give you maintenance intervals at the very upper limit.

It's not a problem if you go over by a reasonable amount, like about 60 or 120 mi. (100 or 200 km). But try to make sure it doesn't happen often.

On the other hand, if you don't ride much,  the oil also degrades simply over time inside the crankcase. It's advisable to change it once a year. It's not that expensive and your engine will thank you.

9th Ignoring SAE ratings or other properties

We mentioned earlier that it's not good to change the type of oil and that you should use the one that's right for your bike. The same goes for ratings and qualities. If the manufacturer requires a certain SAE grade, stick to it.

The engine's design depends, to a large extent, on that SAE grade. For example, the distances between moving parts, the pump's pressure, or the thickness of the film the oil forms. All of these depend on that grade.

JASO anti-friction ratings or API, which classifies oils by how current they are, are also important. They determine how they behave inside the engine  and the oil has been designed for that behavior.

You can, within reason, vary the SAE a bit.  Usually, the owner's manual gives you SAE ranges depending on the temperature at which you'll use the bike. 

In winter, you can use a lower SAE so that when it's cold, it can reach the cylinder head more easily. But don't go outside the recommended ranges.

Varying the rest of the ratings should only be done in very special cases. I would always ask a specialist what the consequences will be.

10th Not checking it again

I've already changed the oil and I can forget about it until another 6,200 mi. (10,000 km). No.

First, there are "very tricky" engines that, when you change the oil, require a few miles of use for the oil to reach all parts of the engine.  When this has happened, you may find that you're a bit low on oil. Then you need to correct that imbalance.

In any case, just because manufacturers say the oil can be changed every 6,200 or 9,300 mi. (10,000 or 15,000 km) doesn't mean it's set in stone. It doesn't mean there will never be any consumption, a small leak, or any other issue

It's still a good idea to check the oil level and condition every so many miles.