Fork oil capacities after an oil change

Good afternoon, learned collective.

Are there any recommendations for fork oil viscosity?

The Gospel According to Honda says 5W, but I’ve read that 10W makes the front end a bit firmer, especially with Bibendum (ie me) on it.

Also, for various reasons I’m convinced that there’s next to no oil in them currently, so is there a figure for the oil volume required if it’s a drain and refil rather than a complete refill after a strip down?

I’m asking because I’ve seen conflicting answers on other sites, so I’d prefer the opinions of you experts on this site.


Undo the drain plugs,take the fork caps off and pump the forks up and down until no more oil comes out.
I use 10wt oil 455cc in the right fork and 475cc in the left

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Thanks, Bill. As always, you’re a Gentleman and a Scholar.

Stupid question no1 of many:

Where is the drain plug on the LH fork leg? The right hand’s been done, but I can find no reference to the LH drain.

Stupid Q no2:

With 6 psi in the forks, and oil in both, (the amount that came out of the rh fork suggests that the lh has oil in it) the forks bottom out under braking. Any ideas?


The left drain is at the base of the antidive unit on the rear of the fork.
10wt oil will certainly help with the bottoming out problem,as you have done your static sag already I would try the heavier oil first before changing anything else

If the forks are bottoming out I would strip them and make sure the valving is assembled correctly. On 3 of 3 sets of R forks ive stripped, the valving was assembled wrong. Felt like there was no oil in the fork legs.


I’ll attack this the lazy man’s way and do the easy things first.

If the 10W oil makes no difference, and considering that all was fine in Oz before the Australian Eejit got his hands on it, it may well come down to a strip and rebuild.

I’m not convinced the forks were stripped for painting. The TRAC body certainly wasn’t removed, but that in and of itself is no guarantee that he hasn’t buggered something up.

The rebound adjuster operates in detents as it should, as does the TRAC selector, but again, that’s no guarantee that the internals are right.

Is it possible to get the sliders off without pulling the legs out of the headstock yokes?

I think you can get the sliders off with the tubes still clamped up but I strip mine on the bench.
Probably damage fork seals that way and then you need to pull the tubes anyway.

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Good point well made.


Having drained the forks, I pulled the springs out just to be sure that they were the right way round. All good.

The amount of oil that came out of the lh fork leg was about 200cc, so even allowing for some residual oil in crevices miscellaneous there was less than half the requisite amount in it.

Having topped them up to the correct level with 10W oil, and put 12 PSI in them, the bottoming out issue has vanished.

I test rode it afterwards, and it’s much more positive, with no bottoming at all.

Thanks for the input, all.