My bike is from 1975. It sat around for years, then the last owner never rode her. So, needless to say, Georgia needed some work. To pass inspection, the tires and fork seals were replaced, carburetors and fuel lines cleaned, and she got a new horn. What didn’t happen at the shop was an oil change.
For some bikes, changing the oil properly is time intensive. Georgia is a CL360 with a 4 stroke engine, 2 cylinders, 2 carburetors, and 6 gears. It’s hard to tell from a dipstick how dirty oil is, and since we know the bike sat around for years, I decided to give her a proper oil change. Jason and I downloaded the manual and got to work.
What we didn’t know before we started was what exactly was involved in properly maintaining the engine oil. On cars and newer bikes, changing the oil is pretty simple: drain the oil, change the filter, fill the oil pan with fresh oil. Not so with this and similar old bikes.
It’s very easy to overburn oil and destroy the cylinders in an engine. Proper lubrication is essential for an engine’s long life, fuel efficiency, and smooth running condition. A couple days ago, I thought I could smell burning oil from Georgia’s engine. Plus, she seemed to be running a bit rough. Hence, the urgent decision to change the oil.
I looked all over the internet to make sure we did it correctly but couldn’t find anything aside from the manual, which doesn’t give too many images to help. So, I decided to write it down here, and add some pictures.
On a Honda CL360 (and CB360), the oil is contained within the crankcase, which is where all the gears are. To filter the oil, it runs through a centrifugal oil filter, which spins forcing sediment to stick to the sides of a rotor assembly. The filtered oil then spits out of the rotor to recirculate into the engine. Larger particles sink to the bottom of the crankcase and are filtered by a metal screen. When the oil is changed on this kind of bike, both the rotary filter (centrifugal filter) and the metal screen should be clean. Otherwise, dirt in the crankcase will be recirculated and will bog down the engine.
First, you should warm up the engine to warm the oil to loosen it so it drains easier, but not too hot that parts cannot be handled. Then remove the oil drain plug with a 17mm socket wrench with a pan underneath to catch the old oil. Make sure you have the metal gasket (looks like a washer) with the plug. If the drain plug is too tight, try putting an iron pipe around the socket wrench handle for more leverage.
While the oil is draining, you can remove the parts that need to come off in order to get to the oil filter and screen. Since these parts are inside the crankcase, the crankcase cover must come off. To get the cover off, the rear brake lever, foot peg, and kick start lever must also be removed. (On a CB360, the exhaust pipe must be removed. Now are you starting to understand why motorcycle oil changes can get expensive at a shop?)
While removing these parts, it can help to take pictures of what you are removing to make sure you replace all the parts properly. Particularly, remember how the brake pedal is angled, since it can go on at a number of different angles. Also be careful that the brake light spring is not overstretched when you disconnect it.
When you remove the cover, you might have to loosen it by carefully striking the cover with a mallet. (We used a hammer and bunch of newspaper folded up to keep the case from getting scratched or dented.) Also make sure that you take the cover off at an angle, starting at the left edge. The gasket, which might be stuck to the cover can pull off the gear below the centrifugal filter. If the gear becomes loose, make sure when you put the cover back on to realign it with the filter gear. Also, make sure the gasket is in good shape. If it’s torn or shredded, replace it.
The screen filter at the bottom is held by a metal assembly with 3 bolts. To clean the screen, the entire assembly must be removed. Then the rubber housing framing the screen can be removed.
This is what the filter screen looked like:
Since there was sludge and metal shards from the engine in the screen, it needed to be cleaned off. We used turpentine to loosen the sludge, then rinsed it with water and let it dry. (Remove the screen from the metal assembly before using solvents to clean the screen. When replacing the screen, make sure that the rubber housing wraps around the metal frame all the way. I used a flathead screwdriver to ease the edges around the frame.)
Cleaning the oil filter requires dealing with several parts: the rotor cylinder, the rotor cap, a rubber gasket, and a metal clip holding in the cover. First, the metal cover clip must be removed by pinching together the two ends with needlenose pliers and pulling it out.
Then, the cap must come off. Some say to use pliers to remove the cap, but this did not work for us. Instead, we got it off by inserting a flathead screwdriver into the holes in the center of the cap, gently leveraging it off by rocking the screwdriver little by little around the circumference. Be careful not to shred the gasket, which is just behind the cap.
Sediment from used oil collects onto the inside surface of the rotor, which should still be attached to the bike. This must be cleaned out, or else the sediment can continue to build up and cause the rotor to stick. I used a thin flathead screwdriver to scrape out the sludge, then used a rag with some oil on it to wipe it clean. (Don’t use WD40 inside the crankcase. Use clean motor oil.)
After the sludge is removed from the rotor, put some clean oil in it so that when the engine is started, it will lubricate immediately. Also, wipe down the rest of the crankcase, removing any sludge. Replace the rotor cap with a good gasket pushing it in until you can see the ridge where the metal clip goes. Make sure the tab on the cap lines up with the line on the outside edge of the rotor. Then pinch the metal clip ends together to fit it against the cap to hold the cap in place.
Once the sludge is wiped off and the filter and screen are replaced, the crankcase is ready for fresh oil. Carefully attach the crankcase cover. Be careful not to dislocate that gear beneath the rotor assembly, as mentioned above. If the cover doesn’t seem to go back on, that gear might be out of place.
Once all the screws are back in the crankcase, the oil drain plug is replaced with its metal gasket, and the kickstart lever, foot peg, and brake lever are replaced, fill her up! We used 2 quarts of oil for “older engines.” The manual says to use an oil with detergent, and another vintage Honda owner recommended synthetic oil. I use synthetic oil in my CRX, so it makes sense to use it in these old classic bikes.
Oh, yeah. Be environmentally kind and put the old oil in the empty oil containers and take them to a service station where it can be safely disposed or recycled (we hope).
After the oil change, Georgia seems to run smoother. No more burning oil smell. Yay.