Hitchcocks Forum

Hi All,

Can someone confirm, can I change fork oil in situ?
I have Pete Snidal’s guide, a workshop manual anddddd YouTube! One site shows just removal of bottom nut and top to change oil.
Others show fork removal.
To me, the nut at the bottom looks like other forks I’ve done where it holds the damper rod; not on RE bikes I hasten to add.

Can someone enlighten me.

Thanks


Oh... just a question as I have a litre of it. Do you think BMW Aeroshell 4 fork oil would be too thin? I think it might only be about 5 SAE.


John

Judging how hard the front suspension is on my 2004 350 is, using ATF, the thinner the better.

Should get most of it out by removing the bottom nut. You'll need to top cap off too so it doesn't hold a vacuum. You'll also need to pump them up and down a few times to evacuate the damper rods.

This is a situation where flushing with a thin oil of some sort may be a good plan when you see the state of what comes out.

Should be possible in situ. The big nut is both the damper rod fixing and also the oil seal. However, after many years of use the inside will be full of crap and these forks are really easy to remove to give them a proper clean. You just need a big hex to unscrew the fork leg from the upper clamp.

Ditto Wheater's comments on the oil weight - I have lighter springs and 5W for off-road work but there is still no pitching on the brakes or yoyo-ing after a bump. The oil is only there to damp out oscillations in the spring so my preference is as light as you can without this happening. This will also give the benefit of a better response over sharp bumps as it will take more to hydraulic lock the damper. As I said it's a quick job to change so give the 5W a try - you can always switch to heavier oil if you notice the front behaving badly after a bump.

Stuart

Interestingly, halfords do multigrade fork oil. I got onto it after overheating the forks on my sportsbike by a protracted bout of riding like an idiot up in the highlands. To the point they lost most of the damping, you couldn't hold onto the fork leg they got so hot.

Thanks all, nice to know I can do in situ.

I’ll judge the state when I drain them. If really crappy then I’ll plan a fork strip.

Nice to know I should be able to use the fork oil I have, I think I have more than a litre.


John