75 900ss fork rebuild

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Macdesmo
750 GT
Posts: 165
Joined: Tue Oct 07, 2008 2:35 pm
Location: Wide Bay Australia

75 900ss fork rebuild

Post by Macdesmo »

I have just looked in Steve's Data for the volume of fork oil for my 1975 900ss and it is less than what is stated in the owners handbook. Do I run with the 280cc per leg as stated in the manual or is there a different volume that works better. The forks are standard.
Ian
Lumpy
SD900 Darmah
Posts: 329
Joined: Sun Mar 25, 2007 5:49 am

FWIW

Post by Lumpy »

FWIW I suffered the same dilema after I put new seals in the forks of my 82 SS. I went with the higher figure. I mean, more is better right????
All jokes aside I can`t remeber if the figure off this site was the higher figure than the mannual or visa versa. Sadly I drained the forks without taking any notice of the volume. The good news is it`s still in there to this day some 3 years down the track and working well. I could`nt really tell you if there was any difference in performance as I also put a set of progresive fork springs in there at the same time so I put the better feel down to those rather than the oil volume.
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abmartin
SD900 Darmah
Posts: 323
Joined: Tue Apr 10, 2007 5:08 pm
Location: New Brunswick, Canada

Post by abmartin »

My source (Mick Walker) says to disregard the handbook and use 230cc for an SS/MHR/S2. He also claims that the racing program used ATF rather than 20 grade oil. The only forks to take 280cc are the original leading axle ones.

Bruce
1979 900SS
Fredericton, NB
Canada
Lumpy
SD900 Darmah
Posts: 329
Joined: Sun Mar 25, 2007 5:49 am

Interesting

Post by Lumpy »

Thats interesting. Forgive my ignorance but I`m guessing that oil volume has no effect on dampening, the viscosity handles that. Is that right??So the fact my forks have 280ml, some 50ml too much oil on board does that mean if I hit a big enough pot hole and bottom out my forks my fork seals could shoot out and hit me in the visor due to the hydraulic effect??? At least I did go for ATF so I got that right.
One of the other reasons I went for the higher figure was that when I stopped at the lights and sat up after a minute or 2 the front end would pop up, although I suspect that could have been the springs which have been replaced with progressive units. Although I thought that a little strange as the original springs had only some 20,000k`s on them.
Macdesmo
750 GT
Posts: 165
Joined: Tue Oct 07, 2008 2:35 pm
Location: Wide Bay Australia

Post by Macdesmo »

The 230 figure is what Steve has listed I think. I was going to use a dedicated 10wt fork oil as apparently all ATFs aren't created equal.
Ian
Vince
750 Sport [BEVEL]
Posts: 203
Joined: Tue Nov 09, 2004 12:28 am

Post by Vince »

I have Cerianis on my Laverda and run 7 wt fork oil at 120mm from the top of the leg with the springs out and the fork bottomed,that a lot more than the factory spec and they work well with Emulators fitted.The higher level effecte bottoming under brakes,what you want is the tyre keeping contact with the road and still having some travel left to handle bumps with the forks down under brakes,the oil level controls the last bit of travel,if your not using enough travel the level is to high and visa versa.Start with a cable tie on the leg with no oil and set it at full travel,add your oil and ride a bumpy road and use your brakes and check how much travel you use and adjust to suit,that is if you actualy ride them,sorry a little Laverda humor.I weigh 125kg,I like a soft ride to handle OZ bummpy roads,heavy wt oil does not work well in the real world,maybe race tracks but not around me
Macdesmo
750 GT
Posts: 165
Joined: Tue Oct 07, 2008 2:35 pm
Location: Wide Bay Australia

Post by Macdesmo »

Vince,
The desmo is going on the road. I have got to get the road worthy certificate first. I have had plenty of triples and am waiting to get an SFC as well.
Ian
Vince
750 Sport [BEVEL]
Posts: 203
Joined: Tue Nov 09, 2004 12:28 am

Post by Vince »

Good to hear,I like to see them ridden as they were make for
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