Forks 1100r

[harri183]

I take on board what you say but if I went with he distance of 120mm not extended I would think I will go from 275cc to about 50cc. Cheers

[harri183]

So, drained all the oil out 295ml each side which again is the correct amount. The forks travel now as normal so too much oil or an air lock??.

[Al]

Basic calculation of volume of top leg without measuring it; Pi x r squared x height give approx. 285cc.
That is an estimated internal radius of 14mm and a height of 400mm (actual leg is probably nearer to 500mm+)
The space at the bottom of the outer leg when the forks are compressed is cancelled out by the damper rod which takes up volume in the inner leg when compressed. That leaves the tiny gap between the inner and outer leg which i am going to call 10cc to a total of 295cc when fully compressed if you dont measure the 120mm of air gap above the oil in the inner top leg as was suggested.
So they must have been airlocked if they are working perfectly now.
AL

[harri183]

Working perfectly because there is no oil in. Are we saying 295ml is the correct amount? Cheers

[Al]

No, 120mm from the top when compressed and the springs out is the correct amount.

AL

[harri183]

Cheers will give it a go.

[harri183]

So only managed to do one fork leg as I have now run out of oil but the manual must be wrong as I have put 350ml in to get to 110 air gap with the fork fully compressed and no spring. If I was to do it as per manual which I did first time then to get the 110mm air gap with the fork fully extended it takes a hell of a lot of oil. Will do the other leg tomorrow if I can find somewhere that sells fork oil on a Sunday and see what it feels like. Cheers everyone.

[Al]

Let us know how you get on. One reason why i dont use a volume measurement for oil is because for some mysterious reason; my top legs are 1/2 inch longer than they are supposed to be for my bike, i have no idea why. Another reason is because i have valves in the forks and also very short linear springs with a bit of plastic tube. The linear springs are thicker wire and take up more volume than standard wound springs. The plastic tube takes up hardly any room at all. If i had to calculate the effect of all those variations on oil volume i would have a mental breakdown. Thankfully i dont need to. I just set them by the air gap at the top and all's well.

AL

[harri183]

All fixed and riding as plush as my semi active ohlins. So the problem was too much oil as I measured the air gap with the forks fully extended not fully compressed. So set to air gap 110mm with the forks fully compressed and it rides spot on to the official manual is wrong. Thanks for all the help.

[Al]

That's good news well done.
AL