Changing the oil in your scooter

What I'm going to describe is how to change the engine oil in a 50cc chinese scooter with a 4 stroke engine. The procedure should be pretty similar on 150cc and 250cc models with 4 stroke engines. 2 stroke engines mix gas and oil and so have no engine oil to be changed.

If you just purchase a new chinese scooter if will come with cheap break-in chinese oil and should be changed after 1 week to 1 month tops. After this is changed I'd recommend changing the engine oil at least every 1000 miles, and the transmission oil at least every 2000 miles. Regular oil changes are the easiest and cheapest way to maximize the life of your engine. Scooters take so little oil that it should cost less than $5-$10 to do and once you know how to do it it should take you more than 10-15 minutes. It's time and money well spent.

The first thing to do is to warm up the engine. Run it for a few minutes so that the oil is warm. That way it will flow easier. If you run it until the engine is hot, or you change the oil after you come back from a trip, that's OK, but you run the risk of burning yourself on the exhaust or with the hot oil. Be careful.

Find some level ground and put the scooter on its center stand. If the ground isn't level you won't get an accurate reading of the oil level when you put the new oil in. To change the engine oil you'll need a wrench to remove the oil drain plus, a flat dish container with a capacity of about 1/2 gallon and a funnel. First remove the "dipstick" which you use to check your oil. I'd also recommend you wear rubber gloves, or at least on on the hand you use to remove the oil drain plus. On most scooters there is a spring which will push the plug out when you have fully unscrewed it and oil will pour out of the drain hole, all over your hand. It's just messy if the oil is cool or warm, but if the oil is really hot it will burn your hand. So wear a glove to be safe.

Put the container for the used oil below the drain plus, loosen it with a wrench and then slowly unscrew it by hand. As it comes lose, the spring will push it down, so be prepared for that. You may drop the spring and a small wire mesh filter into the draining oil, but that's OK, you can fish them out later! Give the oil a minute or two to drain out. Make sure the filter is clean and then put the filter, spring and drain plug back. The spring sits on the plug and the filter sits on top of the spring with the mesh basket inside the spring.

You'll have to compress the spring to start the drain plus screwing into the engine, but once it does start, tighten it up by hand to make sure it's not cross-threaded. If it screws in easily, it's OK. If it doesn't want to tighten, you've probably cross threaded it, so try again. Finally tighten it up with a wrench. It should be tight, but don't overtighten it. The seal is made with a rubber "O" ring. You just need to tighten it enough so that it doesn't vibrate lose (which would be a disaster since all your oil would drain and the engine would seize!). The recommended torque on the drain plug is 1.4 kg.m (about 10 ft.lb)

Now you can add the new oil. It goes into the same hole as the "dipstick" fits in. You'll almost certainly need a small funnel to get oil into the filler hole without spilling it. Check your user manual for the recommended oil type, but on most chinese 4 stroke scooters, regular 10-30W or 15-40W engine oil is used or Big Bore Upgraded engines 10-40W Synthetic Motorcycle Oil. I use Castrol Power RS Racing 4T 10W-40 Full Synthetic Motorcycle oil for my big bore kit scooter.  

You can get a 5 quart bottle for around $12 (try WalMart) which is good for at least 5 oil changes on a 50cc scooter. You can also use a synthetic oil blend if you wish, though pure synthetic oil isn't usually recommended. On a 50cc scooter you'll need about 0.8-0.9 liters which is just under 1qt. As you add the oil, check the level with the dipstick from time to time and fill to the recommended level. When you have the right level, screw the dipstick back in and you're done!