2011-06-17 15:39:21+0000
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Changing your oil sounds simple enough, but even the so called "Experts" can goof it up. I was working in a Honda shop in Salt Lake City, Utah around 1970, when this happened. A new shop opened and we were not too happy. There already were two Honda shops in the city. But, they paid Honda a bunch of money, or so we thought, and there they were. They sold an SL125 Honda single, supposedly serviced it, and out the door it went. Only trouble was they didn't put any oil in it ! So it ran a few miles and seized up. The customer brought it back to them and got another bike. So what did they do with the bike ? They put some penetrating oil down the spark plug hole and got it started again. They then SOLD IT AGAIN, WITH NO OIL IN THE CRANKCASE ! Back it came, but at least now the engine was so trashed that they couldn't sell it again. Truly amazing, huh ?

Change your oil often. If you want to keep your engine going, change your oil often. This is a real simple thing to do, but you must do it right.


  • If your engine uses a wet sump design, the first step is to place a container to catch the oil under the oil drain plug of your engine. Make sure the container is big enough to hold all the oil. Look in your owners or shop manual for the amount of oil your engine holds. The oil drain plug will be on the bottom or side of your engine. Some engines, like the old Yamaha 650cc twins, have two drain bolts.

One thing watch out for. Some engines that have side oil drain bolts, like 1985 and on Honda XR/XL250 engines, also have a gearshift return spring bolt near the oil drain bolt. DO NOT remove this gearshift return spring bolt! If you do, you will have to remove the engine from the frame and do a lot of work to reposition the spring. As I remember, back in the dim dark 1960s there were some two stroke engines that had the same problem. Unfortunately, I can't remember which ones. I went back and checked all my old shop manuals, but I could not find the engine. Oh well, just be aware of this little trap the manufacturer has set for you!

It's best to drain the oil when the engine is good and hot, however, I usually wait till the engine cools down a bit or I just run it enough to warm the oil a bit and get it mixed up good. So call me a wimp, I simply don't like getting burned by hot oil.

Look at the oil drain plug, once you have it out. Some of them have small magnets in them to catch any steel metal particles from the engine. These plugs can be special bolts with a flange head or an allen head bolt with a flange head. Depending on how they are made, the allen head ones can be quite strong or very weak. I took this one out of a 1996 Triumph three cylinder. It's design is very weak. This one is from a BMW twin and it is quite strong. Almost all oil drain bolts will be found to be in there really tight. This is because there is a lot of heat down there and just about everybody torque those puppies down really hard. When you reinstall the oil drain bolts, look up the tightening torque in the shop manual and use a torque wrench to put them in. If you can't find a torque for the oil filter drain bolt, measure the bolt size and use Standard Bolt Torques. This will save a bit of headache in the future.

Using the right torque on both the oil drain bolt and the oil filter bolt can be a lot more important then you might think. On a lot of bikes, there simply is not enough metal around the hole to allow the use of a thread repair kit. Sometimes you can use a bolt that is just a bit bigger or you can use an expanding plug, but the best thing is to not strip it out in the first place. You will find many drain plugs over torqued and absolutely locked in. For these, you may have to make a special Reinforced Socket Wrench.

On dry sump engines, you must find the oil tank and then the drain plug on that tank. There really only two types of tanks. The oil is carried in the frame of the motorcycle. A small, separate tank mounted somewhere on the frame. There are two types of frame oil tanks. The Japanese use the upper part of the top frame backbone and the front downtube to hold the oil. The Oil Drain Bolt is on the lower part of the front downtube.

The British use the top frametube, which bends down forming the rear frametube. The oil is drained at the bottom of this rear frametube.

I'm sure there are others, but you get the idea.

  • After draining the hot, or warm, oil you will want to give a thought to the oil filter. I always like to change the filter because it usually holds a quarter pint or so of old oil. You don't have to and there's not a lot of old oil in there, but...!

Oil filters come in a number of styles.

  1. Screw on Cartridge

    • Internal or
    • External
  2. Paper or Cloth Element

    • Internal or
    • External
  3. Metal Screen

    • Coarse Screen or
    • Fine Screen
  4. Centrifugal

    • Clutch Center or
    • Cup

Cartridge types are just like automotive spin on oil filters. The best way to remove and replace this type is with a special wrench. You can also use a small strapwrench, but they tend to crush in the side of the oil filter during instillation. If the housing is only crushed in a bit, it usually will not hurt anything. If it is badly crushed in, you will need to replace the filter.

Usually the cartridge is located, externally, on the front or bottom of the engine. A few engines like the BMW K series (Brick) have the cartridge located internally, in the oil pan. You can remove a cover and get to it if you have the right tool. if not, you must remove the oil pan and use a strap wrench. Screw the filter in till the rubber gasket touches the base and then NO MORE then 1/2 turn more. Check your shop manual.

The drill is this. Clean the oil filter base on the engine. Dip your finger in some fresh oil and lubricate the rubber ring on the cartridge. Then thread it on until the rubber ring contacts the oil filter base on the engine. Now turn the cartridge 3/4 to one turn more or about 13 -15 Ft. Lbs. of torque, and you are done. DO NOT OVER TIGHTEN. If you over tighten the cartridge it will distort the rubber gasket and cause the filter to leak or even fail completely. Again, check your shop manual. The new Harley Davidsons want you to use your hand and turn it in 3/4 of a turn after the rubber gasket touches the base.

Paper Element oil filters can be inside an engine, under a cover. They can also be carried in a cast, finned, housing, outside the engine. Most of these use a special, large diameter, hollow bolt to hold the cover or housing to the engine. People just love to over torque these bolts. Always use a torque wrench to tighten the bolts. The torque can be as low as 11 Ft. Lbs. to as high as 23 Ft. Lbs. of torque. Check your shop manual. There is a large thin flat washer or Filter Spring Seat used on these bolts that everybody seems to loose. The filters seem to work fine without it, but I always make sure it's put on. These filters have two holes in them, letting the bolt pass through the filter. They are supposed to go on one way and sometimes are marked as to which way to go on. They seem to work both ways.

Another type of oil filter element fits into a chamber on the right side engine. It has one hole. An example would be Yamaha 250cc singles. It's cover is held on with three bolts. The newer ones can only be put on one way, the right way. On some older bikes, the oil filter element, can be put on backwards. If you put them in backwards you will cut off the supply of oil to your engine and it will, in short order, burn your engine down.

Interestingly enough, The same thing will happen to you if you reject Jesus and try another way for salvation. There is only one way this filter goes in, and there is only one way to salvation. Any other way will not work. Even if you really, really, sincerely believe another way will work, it will not. (John 14:6) OK, OK, enough preaching, just put the filter in the right way. If you are unsure, check the shop manual. Each engine is different. The Shop Manual will steer you right!

I had a customer who did this once. He changed his oil and filter and put the filter in backwards. He started the engine and let it idle for about five minutes. The engine then sized. He then brought it to me ! I got the head off and found the rocker arms were literally welded to their shafts. We had to cut the rocker arms and shafts out with a cutting torch. Very difficult. Almost ruined the head. Make sure you put it on the right way.

On some Yamaha four wheelers there is no paper element. Instead, there is a very fine screen that is called a filter. If you are careful you can clean and reuse these. It is in a chamber, and has a cover, just like the paper element. The chamber is located hi and to the rear of the engine on the right side.

On lots of different Yamahas and Hondas the Oil Drain bolt also has a very coarse Oil Filter Screen in it. Don't be fooled just because this is a coarse screen. This screen will catch stuff and can get plugged. If it does get plugged, it can cut off oil flow to the head.

The most primitive type of oil filter is the centrifugal type. It can be in the center of a clutch hub or a separate spinning cup through which the oil is pumped. If you thought that this sounds like it would not do a good job, you would be thinking wrong. At least judging from the amount of sludge, gook and metal filings I have cleaned out of them. On some of these engines, there is a cover you can remove to get at the filter and on others you have to remove the entire clutch cover. You don't see these anymore except on small single cylinder engines. They were used mostly on 50-200cc Honda singles and on early (1960s, 1970s) Honda 125-500cc twins.

  • Now we come to oil levels. Every engine needs a certain amount of air space inside the engine. If you put in too much oil, it cuts down on this air space and increases the engines internal pressure. This can cause an engine to smoke or blow out oil through the seals and/or engine breather.

If you put too little oil in, you blow up your engine, so you had best be accurate in the amount that goes in. One way is to look in the shop manual. It will normally give two amounts. One amount for if you have changed just the oil and another amount for when you change the oil AND oil filter. Sometimes there is a third amount for when you have rebuilt the engine and it is totally oil free. Most engines will have some way you can easily determine the right oil level without draining the oil and putting in an exact amount. This is usually done in one of three ways.

* Oil level dipstick
* Oil Level Plug
* Oil Level Sight Window

All checks are done with the bike straight up and down, usually on the centerstand.

The Oil Level Dip Stick is simply a stick that screws into the side of the engine. It has high and a low marks on one end. Take the Dip Stick out. Clean all the oil off it and insert it back in it's hole. Do not screw it in. Now remove it again and look at the lower end. The oil should be between the High and Low marks. If it is low, add some. If it is high, take some out. The majority of bikes out there have an Oil Dip Stick to check their oil.

An Oil Level Plug is simply a threaded hole, in the side of the crankcase, that is at the proper oil level. Remove the plug or bolt and add oil till it starts to come out the hole. Put the bolt back in and you are done. A lot of race bikes, and some small street bikes, use this method.

An Oil Sight Window has a clear plastic window cast into the side of the crankcase. There are high and low marks on or near the window. The oil level must be between these marks. Add or drain oil to make it so. A lot of street bikes have started using this method. It works good till the plastic starts to discolor, and you can't make out the level easily anymore. Another potential problem is, believe it or not, clean oil. If the oil is clean and the level a bit high, it may look like there is no oil in the window. You add more, still no level in the window, so you add still more. To prevent this, let the bike lean a bit from straight up and down. The real level should show up in the window. If it does not, add a bit more and lean it again till you find the real level. If worst comes to worst, drain ALL the oil and refill with the correct amount (It's given in both the owners and shop manuals) and check the window again.

If you have a small mini bike with a Briggs and Stratton or Tecumseh engine, without a dip stick, you usually fill up the oil to the threads on the oil fill hole. It is a good policy to put all the oil you can possibly get in to it, without it over flowing too much. This applies to both Horizontal and Vertical engines. If it has a dipstick, you usually screw it in to check the oil level. As always, CHECK YOUR SHOP MANUAL !

Adding oil can be a challenge. They never seem to make the fill hole big enough or in the right place. Lots of different funnels can really help here. You can Dribble oil down an Oil Dip Stick and into an oil fill hole. Sounds weird, but it works!

If you change the oil filter, fill the oil up to the right level and then start the engine. Run it for about a minute, and then turn it off. let it sit for several minutes, to let the oil drain from the head, and check the level again. It will have gone down some as it fills up the oil filter, so you will need to add some more oil.

Dry sump engines are a bit different from wet sump engines. On Dry Sump engines you will need to start and run the engine for five minutes or so BEFORE you check the oil level, if the engine has been sitting for any length of time. Even if you have just changed the oil, you will need to run the engine. This is because the oil tanks are all above the engine's oil pump. The oil is gravity feed to the pump. The oil will back feed through the pump gears and into the sump. The longer the engine sits, the more oil seeps back into the sump. You have to run the engine so the scavenging oil pump will pump all the excess oil out of the crankcase and into the oil tank. Once the crankcase is empty of oil and the oil tank full of oil, you can get an accurate oil level reading. Don't check the oil immediately after coming in from a hard run. Let it idle for a few minutes to stabilize the oil level in the tank. Remember to stand the bike upright to check the oil. Do not check it with it on the side stand.

Some engines, like the Honda XR400R, have an additional crankcase oil level check bolt located under the oil filter and oil lines on the right side of the engine. Start and idle the engine for a few minutes an then shut it off and, with the bike upright, remove this oil check bolt. Oil should be up to the threads in the bottom of the hole. Check your owners manual.

I always like to check and make sure that oil is pumping to the head on four strokes. If there is no oil light, there often is an Oil Check or Bleed bolt. Loosen it while the engine is running and oil should come out of it. If there is no check bolt or oil light, and you still want to check, simply take a tappet cover off and start the engine. A lot of oil should spray out, so keep your finger on the kill button. If very little or nothing comes out, you have BIG problems. Look into it !

You will notice that two stroke motors have no oil filters. That is because they have no oil pump. The oil is just in the transmission and all the gears are splash lubricated. The lubrication for the engine is handled by an oil injection pump or by pre-mixing the oil in the gasoline. The oil to the engine is always fresh, but you must change the oil in the transmission on a regular basis.

Engines can be funny critters about oil levels. My RV has a Chevy 454 engine. It will sit at 1/4 quart low and stay there for many miles. If I fill it up to the top of the dip stick it will use oil till I stop refilling it and let it go back to the level it wants. I've seen bikes do this too. Check your oil a lot and you will soon see if your engine is using oil a lot or just wants to find it's own level.

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