Anti dive?

[ian tomo]

Hi all
Could some kind person please explain the operation of the anti dive mechanism on the ST1100? My 2000, st1100ABS/CBS dives under braking alot. I tried clamping the AD piston against the fork leg, to simulate conditions under hard braking ie. piston closing off opening in fork, and when rocking forks they still dive alot. I thought that would block oil passage to stop , or restrict fork movement. Any info would be wonderful
ian

 

[ST1100Y]

I thought that would block oil passage to stop , or restrict fork movement.

Nah! Blocking the damping would seriously compromise stopping ability, just narrowing the orifice (actually blocking off the mains oil way, leaving a narrow bypass but still providing a pressure relieve in case of hitting a bump, audible by a significant 'uiiiet!' ;-) ) to 'stiffen' the suspension to cope with the load shift... Possible that the control mechanism needs an overhaul. How frequent did you change the fork oil? How 'well maintained' have its parts been in the past (replacing fork oil, flushing goo out the fork bottoms, etc...)? Remove the LHS caliper and check if the small piston is still fully moving.

 

[Don-STOC237]

Start by giving the forks a good flush, then fill with the proper amount, to the proper level with a medium weight fork oil. That should improve things a lot. If you need still more, a new, stiffer set of fork springs may be in order.

 

[John OoSTerhuis]

Your anti-dive may have failed, BTDT. See my post here:
https://www.st-owners.com/forums/showthread.php?131740-ST1100-abs11-anti-dive-valve-rebuild&p=1664711&viewfull=1#post1664711
HTH

John

 

[Brant]

Your anti-dive may have failed, BTDT. See my post here:
https://www.st-owners.com/forums/showthread.php?131740-ST1100-abs11-anti-dive-valve-rebuild&p=1664711&viewfull=1#post1664711
HTH

John

+1.......since I don't care to remove,(still do the remove part) clean and assemble forks anymore(had enough practice doing my own Moto-X bikes over the yrs.) the tech that does mine said that is commonly over-looked piece as far as servicing.