Hello everyone, I'm going to change the oil in my forks at the weekend, this has not been done on the bike for years and I'm not even sure how much is in them, was just wondering what the recommended amount is, I know it all varies etc, I'm using it for trials and its a bultaco 159, cheers

Depends on model according to the Bultaco spec charts. 250 = 150cc 350=180cc

of SAE 20 (or ISO VG 68) both models 6.1" of travel.

This viscosity is by preference, a lighter grade will give faster compression and rebound than a heavier grade. I use a 10W30 motor oil.

I have also seen 30mm dia forks = 100cc of SAE 40 (ISO VG150), 35mm dia forks = 230cc of SAE 30 (ISO VG100) and 38mm dia forks = 250cc of SAE 20 (ISO VG68)

Edited November 27, 201411 yr by 1973tr6

180ml regardless off model 15W FOR HEAVY rider 10W for lighter rider.

For what its worth; for me 180 cc dexron ATF. We have helped my friend who has the longer

Pursang springs with 30 weight in one leg & atf in the other @ 180 cc, each, this amount has always worked for me.

This is only my thoughts.

Be sure to have the caps breathing well & turned so they don't accidently get any oil on your person.

Larry

Edited November 27, 201411 yr by lbhbul

Ok, thanks for your help everyone, I shall get some oil at the weekend and drain the old and refill, thanks again