CMS-Japanese Motorcycle Supply Parts

Changing the engine oil - Honda CX500, GL500

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This is a write-up of an oil change without a filter change; we will do one with a filter change soon. Click through to see the how-to.

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Oil Change requirements:

Tool Size Notes
Socket or Spanner 17mm Drain plug
12 or 14mm Oil filter bolt - varies between models
Fresh oil 3L
Paper towel For dipstick
Oil catch pan For used oil

What could go wrong:

Forget to put oil back in before starting motor Bearings starved of oil, catastrophic engine damage
Insufficiently torqued drain bolt Loss of engine oil while riding, engine seizes
Overtorqued drain bolt Cracked front engine cover, oil leak
Omission of oil filter O-ring Oil leak

First off, warm your engine up for a few minutes then let it stand for a few more to let the oil drain back down. Hotter oil is thinner, and will drain more readily - be careful working on a hot engine, though, as the left exhaust pipe is very close to where you will be working. This can be done cold if you prefer. Locate your engine oil drain bolt:


Front of the engine, on the bottom right as you're looking at it from the front. Closer:


Put your oil pan underneath and undo it with a 17mm socket:


Just loosen it slightly with the socket then undo it with a (gloved) hand, pressing in to keep it in place until you feel it has left the threads. Then pull it away quickly - this generally means there's less of an oil mess all over the place.


Undo the dipstick (same side of engine, further back) to let it drain more quickly, though leave it in place loosely to prevent debris from falling into your motor:


Leave the oil to drain - depending on whether it's a warm or cold engine it might be 5-15 minutes, until it's barely dripping:


Once it is done, measure how much came out:


In this case we got out about 1.8L, which is not surprising as the oil was reading low. The oil filter holds a certain amount of oil itself, so don't expect to see a full ~2.5L in the bucket even if it is reading normally. Grab your drain plug and a new crush washer - in this case we're changing over to a magnetic drain plug, so it comes with a new one:


Clean the area that the plug seats against:


Dry it off, screw it back in by hand:


Tighten with your socket. Don't over-do this - it's not uncommon to crack the front engine cover with too much torque here. The drain bolt doesn't require a great deal of force to stay put - there's not a lot of oil pressure in the oil that's sitting behind it.


Now, back around to your dipstick - this is where we add more oil:


Remove the dipstick and grab a funnel:


Hmm. Since the bike is on the side stand, the funnel angle isn't really convenient - it would let it drain onto the ground before it ran into the engine. Carefully chock up the side stand, or use a center stand if you have one:


The engine oil should be checked with the bike on the center stand (or level) anyhow, so this is a useful step if you don't have a center stand. Just be careful not to knock your delicately-balanced bike over. The funnel sits more usefully now:


Pour in your oil of choice. We like to start out by adding as much oil as we removed, checking the level after a minute and then topping it up - it's easier to add some than drain it again.


Let the oil settle for a minute or two, clean your dipstick:


With the bike level, insert it loosely into the hole - letting it rest on the threads, without screwing it in:


Give it a couple of seconds, remove it and check your level:


Bang on - 3/4 up the scale. We like to keep it at 1/2 to 3/4 of the marked section. Now dispose of your old oil appropriately, pack up and take it for a short test ride, then double check that nothing is leaking and that the oil level remains the same.

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