removing GPz1100 antidive units....

I've bypassed the antidive units with braided brake lines and have progressive springs installed as per the GPz750 mods link here. I would like to completely remove the antidive units but apparently removing them will result in too high compression damping. The info says they can be replaced with a machined block of aluminum to act as an oil reservoir. Has anyone done this? I don't quite follow just what is required, size, capacity etc. Did anyone manufacture these at any time?

Post edited by: Fossil, at: 2006/10/14 19:57

I'll try and explain how they work.

When you remove the antidive unit, you will see two holes in the fork leg. When the forks compress, oil travels out one hole, though the antidive, and back into the fork through the other hole. The antidive works by using brake pressure to push in a plunger, to restrict the amount of oil that can flow, by increasing the compression damping.

So, you can see that blocking those two holes is a "Really Bad" thing

I think I have a drawing that gives the dimensions for the block off plate, e-mail me and I'll send you a copy (assuming I can find it on my computer).

Even better, I found it and resized it so I could post it here




If you want the actual size, you'll still have to e-mail me so I can send it to you.


Is that answer satisfactory? :evil: :evil: :evil:

Post edited by: steell, at: 2006/10/14 20:17

That makes perfect sense. Thanks. I've emailed you.

Full sized pic is probably there now

If anyone else needs it, just ask.

I have considered drilling and tapping a hole in the plate extending into the passage, then putting a needle valve in the hole and using it to manually adjust compression damping.

Still thinking about it, since I have not made the block off plates yet

steell wrote:

I have considered drilling and tapping a hole in the plate extending into the passage, then putting a needle valve in the hole and using it to manually adjust compression damping.

Would you be able to get both sides the exact same that way though?
An alternate solution might be to use main jets or similar instead of a needle valve and then just put a plug in the end. I know a guy with a blown alcohol car at the local drag strip, and he has to do this type of procedue due to differences in the air. they check the air before each run and "change the pill(jet)" accordingly. it would make both forks equal, and to change the damping, just get bigger or smaller jets. (you must have lots of spares you could play with, and drill out larger if need be)
Scott

They would have to be awful large jets, those holes are about 10-12mm in diameter. A lot of oil flows through there.

I'll probably never get a "rountuit" however, to much other stuff to do