Let’s assume you have the complete fork unit of the bike, if
you are transporting the fork you will need to re-fit the bolts that held the
fork to the upper crown as the top nuts have holes in them!
First I wanted to get the lower legs back in a presentable
condition, rather than attack them with wet and dry (which is very aggressive
and will end up with a highly polished finish) I decided to remove the corrosion
with wire wool and
Autoglym metal polish. I spent about half an hour on each
lower leg to get them looking kind of how I wanted them – almost a brushed
alloy finish, to get close to the original. I have to say I am fairly happy,
but I am sure I will probably spend some more time on each leg to get them ware
I want them.
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| before and after |
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| Before and after... |
Both stanchions were pitted so I have sourced two NOS
genuine Honda stanchions (one from ebay, one from
Honda M shop) plus a new pair
of oil seals (pattern,
wemoto). The dust seals are in good condition so I decided
not to replace these.
Next was to pull the legs apart, just remove the top plug
unit from the stanchion (this can be tight), remove the spring and drain the
oil.
At the base of the leg is a 6mm hex socket, one of mine was
rounded off so had to be drilled off. Once these are undone the stanchion will
come out, keep a look out for the oil lock piece (often called a foot buffer) at the base of the damper rod.
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| a complete fork leg disassembled |
Remove the dust seal, oil seal cir-clip and price the oil
seal out with a big flat bladed screw driver, now clean, degrease and inspect
everything and note the ‘back up ring’ that sits under the oil seal.
To install the new oil seal I grease the internal and
external part of the seal and seat
(don’t forget to fit the back-up ring) and drive the seal in with a
large socket as close to the outside diameter of the oil seal as possible,
re-install the cir-clip and re-fit the dust seal.
Drop the damper rod through the stanchion making sure the
top out spring is retained on the rod, then add a dab of grease on the end of
the damper rod and fit the oil lock piece – the grease just keeps it in place.
Guide the stanchion through the oil seal making sure not to damage it.
Re-torque the bottom foot screw to torque to 20NM – this
value is not clearly stated in the owner’s manual, but working of the thread
size torque guide (8mm) of 18-25NM. As mentioned before I had to drill mine
off, spares are easy to get, Honda part number 90116-383-721 so it might be
worth replacing these as a matter of course? For speed I ordered form
David Silver spares.
Re-fill with oil, the manual says 150cc of ATF fluid
(automatic transmission fluid), however using this type oil is very old
fashioned. ATF fluid has a very low viscosity so for a modern improvement I
used SAE7.5w synthetic suspension fork oil.
Check your main spring to see if it is still within the
manufacturing tolerance, it should measure a minimum of 482.5mm. Re-fit the
spring with the tight coils to the top and refit the top plugs, these need to
be torqued to 15-30NM.
