Pre Disabled Antidive?

[Christianncg]

Hello. Is there any way to check for a disabled anti dive? My 91 ST1100 when hard braking does a full nose dive, with about an inch to a half of an inch left of fork travel during hard braking. Where would I search for the patch? Do they fail on their own? Thanks.

 

[John OoSTerhuis]

Mine partially failed - the seal on the lip of the anti-dive piston had a piece come off (dunno how/why). Haven’t heard of the unit freezing but you can check for movement by applying the front brake and rocking the ST forward... should move. Otherwise disassemble and inspect.

John

 

[dwalby]

As John mentioned, you should be able to hear a click as the piston at the bottom of the fork moves in/out while rocking the bike with front brake applied. However, I've never been impressed with anti-dive systems in the past, and the ST1100 is no exception. Hard braking with a heavy bike is going to make the forks dive, so don't expect miracles from the anti-dive system, yours may be working normally after all.

 

[Christianncg]

So after a flush and inspection of the plunger I found the seals were all intact. Nothing appears tampered with... what gives? I don't see much movement from the piston though..maybe my brake linkages are not working correctly.

I know the anti dive won't be impressive, but it should at least show difference between braking and popping the shock and not braking, etc. Let me go peep at the caliper bracket. Maybe ziptie the bracket to the fork to emit a response.

 

[Christianncg]

No change with the zip ties, still diving either way. I get no lock up in either instance... Maybe it has been removed? The front fork springs are progressive spung. Not sure if that's how they were at factory or not. Not a real loss it seems because the bike handles fine, might have been removed by a PO. (Not the last one, he wouldn't do maintenance.)

 

[bdalameda]

If your bike has had Race Tech gold valves installed the anti-dive will be disabled due to the drilling of the damper tubes.

 

[Christianncg]

Ok. After changing the oil in right fork, I have stiffness. I added 10w so it makes sense, kinda odd that the right fork affects the left. But upping the old 5w stuff with 10w will do that.

 

[Christianncg]

I doubt it. I want to believe, because it handles like gold. But until it needs fork seals I won't know. I just did a drain and fill. Interestingly someone did a 12v socket (rather professionally I might add) and a k&n filter, so money was thrown at it at some point. No other modifications to my knowledge.


Edit: After riding around town I found that my bike runs pretty spiffy with the new carb sync. I can also hear the click that is mentioned, and as soon as I do, The forks lose travel. I guess they just needed an oil change... go figure. Now on to other issues, like my clutch grab being crap.