How to change a motorcycle’s oil and air filter

Warm her up

First thing to do when changing the oil is to start the bike up and get some heat into the oil. This will make it runnier, so that it empties more efficiently – beware though, if you are starting the bike inside a garage or workshop, make sure it is well ventilated, because if the carbon monoxide kills you, who will change your oil? Whilst the engine is warming up, it’s a good idea to remove some of the bodywork so that you can access the sump plug and oil filter easily.

Drain the oil

Once the engine is nice and toasty, it’s time to drop the oil. Make sure you have a big enough receptacle beneath the bike to catch the waste oil, remove the sump plug (being very careful not to drop it into the oil, and you get extra points for removing it without getting any oil on your fingers) and leave it draining for a good five to ten minutes. It might look like it has just about stopped after a minute or two, but it is always worth leaving it so that as much of the used oil gets a chance to drain out of the sump. It’s best to drain the oil on to a clean catch tray, so that once the oil has drained you stand a better chance of spotting anything in the oil that ought not to be there. Most sump plugs have a magnet on the end of them, so you can see instantly the filings of metal that have worn away inside your engine. Don’t worry about a few little bits of ‘fluff’, but if there are any big lumps of metal in there then you may have a serious problem, needing further investigation.

Remove the filter

Whilst the oil is draining, it is worth getting the filter off. If you are going to the bother (and expense) of changing the oil, it’s always worth changing the filter, too. There are numerous special tools to help you remove the oil filter, such as the big socket type (some filters come attached with a nut on the back so they can be removed with a normal socket) or the sling type, but if you don’t have one of them, a big set of gland pliers will usually do the trick. Failing that, there is always the redneck approach, which is hammering a screwdriver through the body of the filter and using it as a lever to help you unscrew it. Make sure the oil catch tray is underneath, as you may lose a little bit of oil when you remove the filter.

Replace the sump washer

Something many people neglect when doing an oil change is the sump washer. These are made of really soft metal, often copper or aluminium, and are designed to squash into the surface of the sump to form a really good seal (like an O-ring). These ‘crush washers’ are designed to be used only once, so make sure you replace them. If the filter you buy doesn’t come with one, you can buy a box of them for not much cash. You will hear of people trying to warm them up and all sorts to soften back up, but it doesn’t really work and for the price of them, it’s always worth putting a new one on.

Replace the sump plug

With a fresh washer on the sump plug, it’s time to replace it, so give the sump a wipe down and screw the plug back in. It’s best to screw the plug back in with your fingers as much as you can, as it’s unlikely you’ll damage the threads by going in crossed up, if you only go in finger tight. Once it’s started, set your torque wrench to the specified torque and tighten the plug up until you get a click (or a beep, if you have got one of those fancy electronic ones). Don’t be alarmed if it doesn’t seem tight enough and don’t try to over-tighten it, as it’s really easy to strip the threads in your sump. You can buy drilled sump plugs, which allows you to lock-wire them for extra security, something you must do if you want to go racing.

Choosing the correct filter

Once the plug is in and the sump sealed up, it’s time to fit the new filter. There are different options to go for when it comes to oil filters. You can go down the genuine parts route, but expect to pay through the nose for that, or you can go down the cheaper aftermarket route. You can pick up an aftermarket filter for most bikes off the internet.In our experience, the cheaper alternatives, such as Hiflo, are just as good as anything else out there.

Fitting the new filter

When you take the filter out of its packaging, it should have a plastic film on the bottom, to protect the rubber O-ring. Remove the film and grease the O-ring. A touch of grease (or even oil) on the O-ring will help form a seal and it’ll make the filter easier to remove next time. It’s a good idea to fill the oil filter up with oil before you fit it to the bike, as it will take a good few spins of the crank to fill the lubrication system up, so the more bits you can pre-fill, the better it is for the engine when you fire it up for the first time after a change. Take your time when filling the filter up, as it will take a little while for the oil to seep through the filter material. Make sure the filter mating surface on the engine is clean and free from any debris that could affect the seal, and then whiz the filter on, trying not to spill any oil out of it. Like the sump plug, the oil filter will have a torque setting, so it’s always best to tighten it to the correct torque. Again, don’t be alarmed if it doesn’t seem very tight (it won’t be much tighter than you can get with your hand), as all you are doing is tightening on to an O-ring.

Securing the oil filter

It’s not essential (for a road bike anyway), but it’s a good idea to secure the oil filter with a big jubilee clip. If you ever decide to go racing, the scrutineers will want to see a jubilee clip on your filter and they’ll want to see it lock-wired, too. If you like the idea of having some extra security on your filter, fix your jubilee clip on to the filter, as near to the engine as possible. When you tighten the band up, make sure the back of the screw is pushed up to something solid, making it impossible for the filter to turn anti-clockwise, thus unscrewing itself.

Fresh oil

With the sump plug and filter sealing up all the exits, you are ready to refill the engine with oil. Trying to fill the engine up straight out of a bottle can be a messy affair, so if you have got a jug with a spout on it in the garage, then it’s worth using that. If you haven’t got a jug with a spout on it in the garage, there is probably one in the kitchen, but don’t let your Mum see you taking it outside. It will depend on your bike (and how long you have left the old oil to drain), but most motors will take between three and five litres so pour some oil into a CLEAN jug and use a funnel to help you pour it into the engine. Because you will, essentially, be putting oil on to the side of the engine, it helps if you attach a piece of hose to the thin end of the funnel, which can be poked into the oil filler. To help you set the oil level, there will usually be a window or a dipstick. If there is a widow, keep an eye on it and as soon oil is visible, slow down. Be aware that the oil will keep settling and the level will continue to rise after you have stopped pouring, so if you keep pouring until you reach the correct level, you might find you end up with too much oil in the engine. With a dipstick, it is a little more difficult as you have to stop pouring the oil in, wait for it to settle and then check the level. Whichever method you have for checking the level, keep topping up the engine with oil until it is towards the ‘full’ end of the range. This is important, as when you fire the bike up, the oil in the sump will be pumped round the engine, filling all the spaces (the oil pump, filter, galleries and cylinder head) that it had previously drained out of, causing the indicated level to drop.

Oil check

Once you are reasonably happy with the level, pop the oil filler cap back on, but don’t take your jug back to the kitchen just yet. Fire the bike up for a minute or two in order to fill the all the nooks and crannies that had emptied in the draining process. This also gets the oil moving around, which would highlight any leaks from a badly-seated oil filter or sump plug washer. Whilst the bike is running, have a really good look around the filter and the sump plug to ensure there is absolutely no evidence of oil leaking out of the engine. This is why it’s so important to make sure you wipe down any excess oil that’s made its way on to the surface of the engine when you refit the plug and filter. After a couple of minutes, knock the engine off and wait a few moments for the oil level to settle. Once the level has stabilised, hopefully it will be right in the middle of the marks, but there is a good chance that it will be slightly low (its better being too low than too high as this stage as it’s easier to top the oil up than remove it). If it is a bit low, as you did before using your jug and funnel, pop a bit more oil in, this time aiming to be right in the middle of the ‘high’ and ‘low’ marks. Oh, and don’t forget to put your oil filler cap back on (yes, we’ve known people to forget).

Waste oil disposal

There are a few really important rules to keep in waste oil. You mustn’t pour it down the sink or toilet; you mustn’t pour it on your neighbour’s (or your own) flowerbeds; and don’t, whatever you do, drink it – it tastes horrible and will mess up your tummy. Probably. Remember to always place your waste oil in a sealed container and take it to your local household recycling site for safe disposal.

Choosing the right oil.

When it comes to replacing the engine oil in your bike, choosing the right product is really important, but it can be a bit of a minefield. Do you go for a semi-synthetic or a fully synthetic, and what weight do you go for? Your best bet is to stick to the manufacturer’s guidelines, particularly when it comes down to getting the correct weight oil. Most modern bikes will take a 10w40, but always check.

Semi-synthetic oils are fine for most road bikes, but for higher performance engines and racing bikes, a fully synthetic engine oil would normally be more appropriate.

If you are going on the track and you’re dead keen on squeezing every last bhp out of your engine, then there are competition lubricants available that tend to have a much lower viscosity (are thinner), than what you might put into your standard road bike.

Oils like 0w30 and 0w40 tend to be used by those that need all the power that they can get, but they aren’t cheap and need to be changed a lot more frequently than cheaper oils.