CX500 / GL500 / CX650 / GL650 Rear Hub Oil
Check / Change
This page shows you how to check the correct level, and optionally replace, the lubrication oil in the rear drive hub of your CX / GL motorcycle.
Skill : 1. Tools : 1. Personally dirty : 1. Work mess : 2. Space : 1. Time : 15 minutes.
All nut and bolt sizes are given for the spanner size required to fit them.
Skill levels explained.
Tools : 10mm, 17mm sockets; ratchet handle and extension bar; grease gun; replacement oil; torque wrench.
The capacity of the rear hub is 160 - 180 cc of Hypoid EP90 gear oil.
DO NOT USE AUTOMATIC TRANSMISSION FLUID (ATF) OR STANDARD ENGINE OIL.
All the tools, hands, and bike in the pictures are the author's. I am very receptive to comments and suggestions, but you use these pages entirely at your own risk.
The CX/GL family has a shaft drive which requires lubrication oil in the rear hub. Checking the level and doing an annual oil change are the only maintenance jobs you need to do. Compare this with chain drive bikes, which need regular drivechain lubrication and expensive replacement chains and sprockets.
Honda recommend that you check the oil level with every engine / filter oil change but they don't make any recommendation about changing it. I suggest that you change the oil every year, or at the beginning of the "summer bike season".
Take the bike for a short run, to warm the rear hub and its lubrication oil.
General view of rear hub (below).
Remove the 17mm head inspection cover (left) - this is exactly the same as the one you unfasten to check the engine timing for a tappets adjustment job.
Once the cover is off, the level of lubricant inside should be up to the lowermost level of the inspection port (right).
If you're not going to change the oil, simply top up the level, as necessary, from your bottle, until the oil is just starting to overflow. Then replace the port cover, tightening to 6 ft / lbs.
Dave French says "I
find that to save spillage when removing the cap, rotate the wheel gently backwards,
if the level is a bit high, it doesn't pour out over your tyre."
If you plan to drain the oil and replace it, put a small receptacle below the hub and remove the 10mm head drain bolt (left) and allow the old oil to drain out.
Then replace the drain bolt and washer, tightening to 6-9 ft / lbs. Fill the hub until oil is just starting to overflow, and then replace the inspection port cover, tightening to 6 ft / lbs. The capacity is 160-180 cc.
Look and see if your model has a grease nipple (ringed, right) on the forward part of the hub assembly. This is fitted to 500cc models but older bikes may have had some parts transposed from another variant.
If your bike has a grease nipple, give it four pumps on the grease gun (left) to lubricate the shaft drive mechanism.
Road test, check for oil level and leaks, and you're done.
You are welcome to comment on these pages.