CMS-Japanese Motorcycle Supply Parts

Troubleshooting Oil Leaks - Honda CX500, GL500, CX650, GL650

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Oil leaks come in all shapes, sizes and locations... here's some tips for your leaking twisted twin. This list is incomplete and we will be adding photos and more info as they are processed!

If you can't find the oil leak, clean the engine with degreaser, let it dry and then apply a light dusting of flour to the suspect area. You should see a clear trail once the oil starts leaking.

Front of engine

Front engine cover gasket

This can leak at any point around it, and the oil can track back along the left or right side of the bike (or directly underneath). Doesn't require you to drop the engine to replace.

Tachometer/camshaft cover

This can track down and look like a clutch cover leak, or front cover gasket leak. It can be a little hard to see if it's only a tiny leak but there is usually a bit of a mess in that area if it's leaky as dirt will accumulate in the oil.

Clutch cover

This one can track back and get oil on your boot/brake lever.

Clutch actuator

There's an O-ring around the shaft that rotates in the clutch cover; this is another one that commonly tracks back along the engine while you're riding.

Rear of engine

Rear engine cover gasket

This one requires you to remove the motor from the frame to replace.

Pulser cover

Some people have replaced theirs without dropping the motor (unsure which models they were).

Pulser cover weep hole

There's a weep hole next to the pulser cover which can leak oil; if this is the case and the crankcase breather isn't blocked then it's likely that one of the stator wire grommets is misasligned.

Left side of engine

Hole in the side of the head

See here.

Shift shaft seal

This can leave a few drips here and there. See how to fix it here.

Right side of engine

Hole in the side of the head

See here.

Manual cam chain tension adjustment bolt

This one is a motor-out job to replace, unfortunately. It seems to be able to slowly leak a reasonable amount of oil, which will spread downward from the bolt.

Timing inspection cover

There's an O-ring under the cover - or under the breather, if you have a bottle-style crankcase breather. This can leak oil.

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