Learn how easy it is to do the most satisfyingly straightforward and money-saving maintenance job there is.
This procedure covers typical and popular four stroke wet sump machines. It does not cover dry sump bikes (popular in some off-road styled machines like the Yamaha XT600, Rotax engined BMW F650 etc) or two strokes, though the principles are broadly the same.
Low to medium
Tools and stuff:
Your bike’s manual for torque specs & capacities
Spanner, hex key or socket to loosen sump plug
Torque wrench with socket or hex key to tighten sump plug
Oil filter removal tool
4L motorcycle engine oil & funnel
Sump plug sealing washer
Gloves or plastic sandwich bags
Old water bottles/sealable containers
1. Get bike’s engine warm but not red hot. A brisk 15-minute trip is all it’ll take. If you’re new to this you might not realise that warm oil is less viscous and so drains from your engine quicker and more completely. Here’s a scientific gravity race to prove the point:
2. If you have a naked bike or one with a well-designed belly pan (the plastic fairing part that fits under your engine) and you can see both the sump plug and filter as you squint beneath then it’s happy days. If not, or you have a protective sump guard in the way, remove it. Guards and belly pans are usually held on with four hex-headed screws and once removed will expose the bottom of the engine.
3. Locate the sump plug – an obvious looking bolt or hex headed bolt on the bottom of the engine – then clean around it. An old toothbrush or some rags and kitchen spray will come in handy here. Cleanliness is next to godliness with oil changes for no outside crap must find its way in. Inspect your good work with a torch.
4. Find the correct spanner, socket or hex key and hold it in place. Then using the palm of your hand as a makeshift hammer, knock the other end of the spanner to crack open the plug a touch so you are able to remove it with your fingers but leave it in situ for now.
Top Tip. Not sure which way to turn the sump plug because you’re working upside down? Imagine you’re lying under the motor looking up at the sump plug. Always remember you undo the plug anticlockwise as you look at it.
5. Find a convenient drain pan and place it centrally beneath the bike. A small pound shop washing up bowl will do, or even better cut the side out of an old 5L oil can and use that forever more. Make sure it’ll hold at least 4 litres.
6. Don some latex gloves or put your hand in a sandwich bag as protection, then undo and remove the sump plug by hand.
Try not to lose the sump plug or sealing washer into the oil or you’ll need to go fishing with a magnetic probe.
7. Leave it draining a good 15 minutes. Cup of tea is enough time. Make sure the oil is definitely going in the pan before you leave – once it drains down a bit the spout of oil tends to change direction.
NB: Ignore claims you must crack open the oil filler cap to let the oil out without it glugging. The engine crankcase is always vented (usually via the airbox) making this unnecessary.
8. Inspect the sump plug. Some are magnetic, so be the mechanic and look at any metal particles the plug has attracted. A fine swarf or paste that can be squished between the fingers is A-OK.
Occasional metallic stubble may also be evident – especially if your engine shares the oil with the gearbox like most modern bikes. Nothing to worry about here either.
But like chunks or identifiable engine parts? Not so good.
9. Clean up the sump plug and set aside.
All manuals will tell you at this point that you must change the sump plug sealing washer to avoid leaks. It’s a good idea and vital if the washer is a hollow deformable crush washer or has a rubber seal bonded to it. If it’s a plain one though and in good condition use your nous and decide for yourself. I’ve used the same washer on my BMW for the last six oil changes and in doing so have saved somewhere in the region of £1.20 in the process – the kind of savings that pay for the hosting of this blog. I’ll leave it for you to decide if it was worth it.
10. Next remove the oil filter. Unless your bike is pre ‘80s it will have a convenient car type spin-on disposable oil filter like this one.
Before you start, clean around the old filter base just like you did with the sump plug. You’ll now need a removal tool to get the thing off. A universal strap or chain wrench will do easily accessible externally mounted filters like this one:
Or this one (my personal preference):
It fits around the filter body like so:
Hidden internally recessed filters that you can’t get to with universal tools like in the BMW oilhead require a tool like this made for the specific size of filter:
Just make sure you have the right one. Untighten a turn or two then simply spin the filter off by hand. Oil will come out so be careful of mess.
Top Tip. If your nifty filter tool keeps slipping or you’re wrenching in the shade of a tree without the benefit of such things, carefully pierce the filter with a hammer and flat bladed screwdriver, insert the shaft and use it as a makeshift lever. Filter defeated.
11. Wipe clean the mounting area at the base of the filter with a rag. Unbox your new filter and turn it upside down. Note the rubber sealing washer bonded to the base. With your fingertip apply a little oil to this washer to help you reinstall it correctly.
Top Tip: Old filters can stick to the engine through the action of heat and time, making them a real bear to get off. I’ve recently heard some mechanic’s lore that using old engine oil when you mount the new filter prevents ‘stiction’ better than new engine oil when you come to remove it. Not sure of the validity of this but might be worth a try.
12. Now wash your hands or don a new pair of gloves. You need clean hands because you’re going to screw the new filter on to hand tightness only and heavens to goodness you don’t want to be slipping around on it.
Start the new filter on its threads then tighten down until the filter stops against the engine block. Now tighten at least a further half to three quarters of a turn more – or as tight as you can reasonably go with your hands unless you’ve been taking steroids. That’s it.
13. By now no more oil should be dripping from the sump. Move the old oil somewhere children or white dogs can’t stand in it, wipe up the area around the sump plug so it’s clean and reinstall the plug with a new washer if you’re a super keener. Check your manual and tighten to factory torque specs – if you’re new to this game, double check your measurement on your torque wrench before you start. The tightness of sump plugs is generally pretty minimal, like 20 lbs-ft.
14. Now open the oil filler on your bike’s engine and yes you guessed it, wipe it clean. You are now going to refill the engine with oil. What oil? I won’t debate that here. In biking terms the motorcycle forum oil thread is a thing of legendary arguability, but for non oil nerds (ie normal people with healthy hobbies and good mental balance) I recommend you use a motorcycle specific engine oil of the viscosity and grade your manufacturer recommends (and in doing so I neatly avoid giving any specific recommendation). Oh, if you must, Rock Oil Guardian semi synthetic 10W/40 will suit most bikes from the ‘70s on in the UK climate.* Cost: about £27 for 4 litres.
*Note: There is a debate around backwards compatibility of modern oils for some machines, but that’s for another article…
15. Use a funnel or cut the top off a drinks bottle if you don’t have one and slowly fill with the correct quantity. Careful not to overfill! Most manuals give you an engine oil capacity with filter change and without. It is always the higher capacity when you have changed the filter, as the filter is empty at this point.
16. Let the oil settle a moment and check the level. If you have a dipstick, wipe it clean, make sure the bike is perfectly vertical then rest the stick on the threads of the filler hole. Don’t screw it all the way in unless your manual specifically tells you to. The level must be between the minimum and maximum marks and preferably three quarters of the way up to full. If you have an oil sight level glass instead, again make sure the bike is held vertically on the centrestand or you have an assistant to balance it while you check the level – again there will be minimum or maximum marks which your level must fall between. On the BMW there’s even a red dot to show the optimum level. Handy.
17. Happy? Screw in the filler cap and start the engine. If you have an oil light it may take a few seconds to go out as pressure builds up in the system, again. Equally if you have any oil pressure dependent tensioners in the engine you may hear a tapping or rattling which should go out in a few seconds as the pressure builds back up. All perfectly normal. After a brief run of the engine, shut it down and let it sit again for 5 minutes.
18. You’re now going to get a final oil level. As the new filter is now full of oil, the level will have dropped a little in the sump so top up a little at a time until you are happy you’re between the two marks and preferably in the range of at least three quarters to full.
AGAIN DO NOT OVERFILL! Over-filled engines can suffer crankcase pressurisation and shoot oil out of the breather into the airbox or even blow out seals (particularly sight level glasses which are a push fit). The oil can also get over-aerated as it’s thrashed about ,meaning pumps fail to pump as efficiently. Strange as it may seem, oil starvation can be a result.
19. Screw in your fill plug and do a final check around for leaks near the filter and drain plug. If you’re happy, put the belly pan or sump guard back on and pat yourself on the back (or if you’re old and stiff, get someone to do that for you). You just changed your oil and saved yourself a few quid in doing so. Enjoy the Zen-like peacefulness that this will bring to your life.
20. Oh yeah, take your old oil for recycling in sealed containers. I knew there was a 20.