Anti-dive. Why block off plates?

[glib]

After reading some threads on blocking off the anti-dive and reading the service manual, I can’t see why block off plates would work any better than simply removing the supply line since they are only activated by brake pressure. If you make a block off plate with a connecting channel to prevent blocking the flow of fork oil, you have to guess at how much flow to allow—or buy one and trust that it is designed for optimal flow.

Removing the supply line to the anti-dive units immediately firmed my brake lever. Haven’t ridden it yet.

I also wonder if anyone anyone can accurately describe why they don’t work (we’ll concede that they don’t by popular opinion—but why) because they seem to be well thought out, including internal emulators to provide for harsh bumps while braking.

[mmattockx]

I also wonder if anyone anyone can accurately describe why they don’t work (we’ll concede that they don’t by popular opinion—but why) because they seem to be well thought out, including internal emulators to provide for harsh bumps while braking.

Anti-dive systems that function by increasing compression damping don't work because:

1) They only slow the rate of dive, they don't actually reduce the overall amount of it.
2) They make the forks harsh over bumps while the brakes are being applied, exactly what you don't want when braking hard on choppy pavement.

FWIW, I did the same as you and simply removed the signal line from the anti-dive unit and then plugged it with a bolt. Works fine on my 1100E as well.


Mark

[Steve]

I have never had a bike with the anti-dive feature, but I think I have an idea why they are not liked.

It is my understanding that it takes pressure in the brake line to move a mechanism in the fork damping system. That system needs to move before you actually start to build enough pressure to brake. It's that delay and lack of initial feel that is not liked.

The block-off plates should have a channel to allow fluid flow between two areas, but I have only heard that, I have not examined it in detail. Yes, you could simply not install the line from the caliper to the anti-dive mechanism, but that leaves you with the lighter damping and no adjustment. This is all the more reason to not stop with damping, but install proper springs, as well.

.

[Sandy]

I had the anti dive on my 750EF and really couldn't tell much difference. Perhaps it didn't dive as much, kind of hard to really tell if it worked or not. I think most don't like it because it's sort of a pain to get bleed properly and I don't blame anyone for bypassing or removing the system. As for dampening, other than braking, it makes no difference to the regular dampening and there are no dampening adjustments on the anti dive units so simply removing the line will only defeat the anti dive. The block off plates are only for cosmetic reasons for those that don't want the units installed. They do need a bypass slot between the 2 ports to allow fluid to pass.

[glib]

Mark, Steve and Sandy

Thank you. Perfect. You confirmed my suspicions. I guess the anti-dive were good on the drawing table but not well engineered.

I am ordering Sonic Springs and Race Tech emulators. Not sure what weight fork oil to use yet so there’s that, but I have a good plan now.

[salty_monk]

In theory you could use the size of the bypass channel as a method of adding additional compression damping. In practice it's better to give it a big channel & use a cartridge emulator for that job as it's easily adjustable.
I guess a block off plate with an adjustable slot could be made, suspect there is not enough demand out there for it to be worth anyone taking it on.
When the system is working well it feels fine to me (in a wooden Suzuki GS brakes sort of fine)....

[glib]

In theory you could use the size of the bypass channel as a method of adding additional compression damping. In practice it's better to give it a big channel & use a cartridge emulator for that job as it's easily adjustable.
I guess a block off plate with an adjustable slot could be made, suspect there is not enough demand out there for it to be worth anyone taking it on.
When the system is working well it feels fine to me (in a wooden Suzuki GS brakes sort of fine)....

I would think that a bolt of the same diameter as the bypass channel with its depth secured by a locknut and sealed with an o-ring would work well as an adjuster of the compression dampening.

As for me, I’m anxious to feel the braking response of some nice tight single rate springs and emulators.

[limeex2]

I would think that a bolt of the same diameter as the bypass channel with its depth secured by a locknut and sealed with an o-ring would work well as an adjuster of the compression dampening.

As for me, I’m anxious to feel the braking response of some nice tight single rate springs and emulators.

It works fantastic!

[sharpy]

Mark, Steve and Sandy

Thank you. Perfect. You confirmed my suspicions. I guess the anti-dive were good on the drawing table but not well engineered.

I am ordering Sonic Springs and Race Tech emulators. Not sure what weight fork oil to use yet so there’s that, but I have a good plan now.

You better read up on race tech web site about installing there emulators before you pull things apart. All info is there.

[glib]

You better read up on race tech web site about installing there emulators before you pull things apart. All info is there.

Actually I did that just before starting this thread. Do you think I missed something?

[Nessism]

A few years back, when restoring a 1983 750ES, I made block off plates and ditched the anti-dive. Normal damping is not metered through the anti dive, so the only requirement for the plates is to make sure the channel in them flow enough oil to allow the damping rods inside the fork to do their job. In my opinion the plates look a lot more clean than a dead anti-dive device hanging on the front of the fork. To make the plates I used 1/4" thick aluminum and normal garage tools. To cut the channel a carbide burr in a die grinder/drill did the job. A very simple project.

[jsandidge]

Ed, by any chance do you have pictures of the plates you made? I'm working on an 83 750E right now. The PO had removed the lines and put a bolt in the hole.

[Nessism]

Ed, by any chance do you have pictures of the plates you made? I'm working on an 83 750E right now. The PO had removed the lines and put a bolt in the hole.

Found the old thread using the search function...http://www.thegsresources.com/_forum...lock-off-plate

Photos are visible using Chrome with the photobucket fix extension

[mmattockx]

I am ordering Sonic Springs and Race Tech emulators. Not sure what weight fork oil to use yet so there’s that, but I have a good plan now.

I have Sonic 1.0kg/mm springs and RT emulators in my 1100E with 10W fork oil. The emulators are set at 2.5 turns of preload. It works well, but I think in spring I am going to change to 12.5W (50/50 mix of 10W and 15W) oil for a bit more compression damping for more road feel. It isn't far off and I don't want it super stiff considering the weight and vintage of the bike, but just a bit firmer would be great for me. I weigh 187lb without gear. Unless you weigh enough to go to the 1.1kg/mm springs I wouldn't start with 15W oil, I think it would be too much for the lighter springs. If you are a lot bigger than I am and need the 1.1 springs then I would say go with the 15W.

Ed, by any chance do you have pictures of the plates you made?

I'm curious to see them myself, having thought about putting a set on once in a while.


Mark

[mmattockx]

Found the old thread using the search function...http://www.thegsresources.com/_forum...lock-off-plate

Photos are visible using Chrome with the photobucket fix extension

I just added the Chrome extension in and the pics are still showing as the photobucket graphic instead of the pic. What am I missing?


Mark