Front fork oil

[Gonemad]

My owners handbook indicates that I should use SAE 20 in the front forks but I seem to be having a problem finding SAE 20, or even 20W - 50, oil here in Norfolk. 
Halfords sell a 5L can of SAE 20 for £18+ but that seems a bit ott for the half litre total that I require. Wilco has a 1L SAE 30 available.
Would that be OK for the forks ?

[chaterlea25]

Hi,
Go to your local bikeshop or off road shop and buy a bottle of medium or heavy fork oil, It works better than engine oil and has been developed specially for forks
It wasn't around when BSA were 

HTH
John O R

[wilko]

I've always found modern thin fork oil useless in ol' timy forks. What's the thickest fork oil you can get these days anyway?Just shove some multi grade in it.

[chaterlea25]

Hi Wilko,
Fork oil is available up to 20w
If the forks are in good condition (which they should be!!) I find 10 or 15 to be fine

John O R

[Gonemad]

Finally, albeit by answering my own question, I can put something back into the forum.

Today I found a distributer in Norwich that had SAE 20 fork oil, Putoline HPX 20 Special Racing Suspension Fluid would you believe.  At the bottom right of the label is does say SAE 20W.
For the benefit of those local to Norwich the shop is Moonraker Motorcycles Ltd, Oak Street  NR3 3BP and the owner is Paul, who is in to ?old? bikes like BSA?s.
The price was £10.13 / L.
When I filled each leg today with the 213cc of oil I was surprised at how little that seemed.  Still, that was what my ridiculously expensive but original E-Bay RGS Owner?s Manual told me.

I hope that this is of value to others.

Angus.

[wilko]

I've used it in the past and it's useless with the tolerances in these style forks. Especially shuttlevalve style.

[Gonemad]

I will let you know next spring, err..that's a pun I know.  If the oil does not perform I will simply drain it out and put in the Wilco SAE 30 instead.

[1959superocket]

Query on quantity if 2 way dampers fitted.

With regard to fork oil quantities whilst it says 213cc per leg does this need to be reduced when using the 2 way damping rods to say 190cc or do you still use 213cc?

Cheers

Stuart

[chaterlea25]

HI Stuart,
To be effective the damper rod valves must be submerged in the fork oil at full fork extension
I find that thinner fork oil than the SAE 20 is needed or the forks wind up too stiff
I add or drain fork oil till I'm happy with the fork action,
HTH
John

[1959superocket]

Cheers I will be using SAE 10 which is medium rather than heavy grade SAE20

Stuart

[KeithJ]

Infinity stocks fork oil, a cheaper one and a more expensive one for super modern bikes.  Harley shops are also likely to.  ATF is also used as, from what have understood, it is close to the viscosity of fork oil and is anti frothing.  If ATF is use, make sure it is changed regular as it is hydroscopic.  Used both ATF and Fork oil and worked find on my forks with dampers.  Would not use multigrade, just looks to be the wrong application.
Keith