Hi all,

Just been down to local garage with a list of oils for front forks - he had none of them so I came away with 10W jack oil.
Does anyone have any idea if this is suitable?? I am going to try it anyway and will let you know how it goes!
If nothing else it might raise the suspension !!

Ian

Ian, I think you might have good results with that oil.
The olny thing that might be a small issue is possibly the jack oil may not have an anti-foaming agent in the formula.

The 10 weight is what I used just 10 days ago when I did mine.
I used SPECTRO blue.
It was the ticket, I now have a better behaving front end

Let us know how the jack oil works out.

RL

Hi there, in my experience 10 is good as long as you dont have potholes (not my case) on your way. I´m using 5w.
Best regards
JAP

My progressive springs came with the recommendation to use 15W. Just experiment and see what you're comfortable with. You won't break anything by using a slightly lighter or heavier oil.

i used 10 weight also ...seems to be good for me ...

ReneZ wrote:My progressive springs came with the recommendation to use 15W. Just experiment and see what you're comfortable with. You won't break anything by using a slightly lighter or heavier oil.

Rene is right on the money with this as everyone has different preferences and conditions they ride in. I've currently got Amsoil #10 medium weight in mine.

OG

An emergency option if you want low cost is to get ATF, that is around the right viscosity and if for instance you wanted to flush the forks ATF would be a good choice and it has anti foaming characteristics too.
Regards,
K-BIKE

Great tip K! I didn't think of that and probably should have done just that as the brown goop that came out of mine was not a pretty thing!

OG

I v.recently used ATF, and found it to be a bit eye-ball rattling. Changed it to 360mL of Motul 10W and the difference was amazing. No wallowing, no too stiff feeling in the front end.

Just changed my fork oil tonight. Well, that was a bloody adventure!

Drain bolts removed and the left leg had about 100mls of festering goop and nothing came out of the right leg!

Started filling-up the left leg (360cc, Castrol 10w Fork Oil) and got as far as 200ml and the fork was full!

Better read the manual now...

Oh, I see. Jack the front of the bike up and loosen the top Allen bolts.
Yep, found the rest of the oil! Well, the shed floor did!

Filled the forks up properly after that and all is good.

Of for a ride tomorrow to see and feel if there is an improvement.

At least the shed floor will never rust...

It took overnight plus some for all the brown goop to drain out of mine Blakey.

OG

[quote="blakey
Oh, I see. Jack the front of the bike up and loosen the top Allen bolts.
Yep, found the rest of the oil! Well, the shed floor did!

...[/quote]



have a good ride tommorrow mate , just back from a run up nebo -glorious (first time on the new tyres)

cheers

The brown stuff is why I use the ATF as a flushing medium, it takes the brown stuff into suspension (no pun intended) and then removing the drain screw allows it all to drain away, then when empty a few pumps on the bars with the wheel touching the ground will ensure any other stuff is out of the fork legs. Replace the drain screw and the fork legs can be topped up with the new fork oil, either BMW fork oil or Bel Ray or even one of the exotic synthetics. The other point about ATF is in an emergency needing to top up the forks it is widely available whilst fork oil may not be, yes it may be too light (average is about 7.5 from memory) but it depends upon ones weight if it will be a problem. For a while BMW fork oil used to be 7.5.
Regards,
K-BIKE

With the 'S' forks fitted to my K100RS I prefer the 5W fork oil for its damping characteristics. 10W is too hard, but may be ideal for the longer travel, softer sprung RT/LT and normal RS forks, or for your extra body weight. 7.5W is still sold in No. America by BMWNA as the preferred weight for any bike without Telelever suspension, though the 10W
'Telelever' oil is a popular option too. I change mine yearly and it comes out only slightly dirty in that time.

Wow! thanks for all replies guys! sadly I am awaiting tax disc to start working before I can get out on the road to test it properly. But early indications seem promising (up and down the drive ahem!) If it doesn't work i think i'll need anti foam stuff in my coffee - cos i'll be livid!!

Thanks again for all replies I will advise after a decent run - unless i get foamed up!!

Cheers all

Well tax in post sticker went in the holder and tried her out with the jack oil in - seems to be a lot better than before but now i have a knock when the bike is being pushed back ( so the suspension legs are pushing the bike upward) mainly after a bump rather than just a smooth up and down, small pot hole type of thing. Preload?? not enough oil?? suggestions??

cheers Ian

I'm thinking not enough oil...

Also, here is some info from the Penrite Oil Co. (Oz oil company) web site, on what to use as a substitute for fork oil.

It states:
The below chart is a cross reference for Penrite oils where they are able to be used as motorcycle fork oils as we do not market specific oils for this purpose. Where ever possible, products that are available in retail pack sizes have been quoted.
The numbers are generally referred to as “SAE” grades.

Fork 2.5 No product
Fork 5 Penrite MB 15 Suspension Fluid
Fork 7.5 Penrite LHM Plus, Penrite PAS Fluid
Fork 10 Penrite ATF DX3/BMV/SIN ATF/MHP/FM5
Fork 15 Penrite ATF DX2/95LE, Penrite Shocker 1
Fork 20 Penrite Shocker 2, Penrite HPSO
Fork 30 Penrite Indus HV 100

For your information.