fork damper types for airheads

[dougcusack]

Does anyone have any information on the differences for the damper rods that were used for the ATE style forks from 74 to 80?

I have searched the ETK manual but it just lists different part numbers but doesn't show the differences.

I have a couple of damper rods. One has the usual 4 holes at the bottom but has a hole 22mm up and then two holes 20mm up and then an additional two holes 10mm higher up.

I also have a damper rod that has the usual 4 holes at the bottom and then has only two holes 42mm up. There is a partially drilled hole 10mm above these two holes.

So I am setting up a new fork and want to know which of the dampers I should use if I am setting up a sport style suspension. Bike is a '77 75/7

Any comments?

Thanks Doug

[20774]

I found this comment by Tom Cutter on the Airhead list:

"Not counting the four holes at the very bottom around the ball check valve,
there are either four (standard) or two (sport) holes. The ones with two
holes actually have the other two holes half-drilled, so you could finish
drilling them if you wanted. (I assume that BMW used those holes for some reason during the assembly process, maybe to mount in some fixture.)

Less holes means stiffer compression damping."

So if you want a sportier ride, go with less holes.

[lostboy]

As you might expect, three holes makes a nice compromise. I have brazed shut the fourth hole in some damper rods and drilled a third in others.