All right. With just a little bit of stuff from the plumbing section and a little bit of work with a drill, my air assist forks are finished and holding air on my 04 Road King. Yippee!

I took a spare set of fork caps, drilled and tapped them for the 1/8" pipe thread the air shocks use. Screwed in an elbow, screwed in the airline fitting, and that's all it took.

Haven't decided yet about where to put the fitting. I'd like it up front, but I don't see a particularly good spot, yet. So I may go to the rear like the old design. Then again, it just occurred to me, one of the nascel mounts should work well.

 

Pardon my ignorance, what is the benefit?

 

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Maybe nothing. But I'm hoping for two main things.

One, the ability to adjust the air pressure and therefore the progressive rate of the springs. Especially in dive or other near bottoming events. The air column above the oil is compressed as the forks are compressed, giving a progressively increasing spring rate as the fork collapses. Increasing the pressure (or decreasing the volume by increasing oil level) will increase the compressed pressure and compressed spring rate.

Two, the ability to quickly and easily change fork oil through the lines going into the fork tubes. I know I can do it via the bottom drain, but I don't care for adding fluid this way. I'm a bit messy and never terribly confident of exactly how much is left in by the time I get the plug in. Will I actually spend much time tuning the suspension via repeatedly changing fork oil viscosity and volume? Probably not. But the geek in me likes having the ability.

 

Interesting.....how much pressure you pumping in? I would fear for seal failure long term....

 

At the moment, I simply put 15 psi in there to let it sit and see if it holds.

As for tuning for ride, I figure I'll play in 5 psi steps to see if it changes things in ways I like. That'll be a bit, as I really cannot ride again yet.

 

Nice! I'll follow this one. Back in the day (1974 and 1975) we were racing Suzukis and Bultacos. We took all the internals out of the forks and had custom air caps machined. We adjusted the oil level and played with the air pressure. It worked well for us.

As for fork seal life, we would go an entire season without any leaks (we always had leaks running stock). The air pressure forced the seals against the fork tubes.

I've wondered if this would work for my UC. We didn't tie the forks together, simply had fittings machined in each fork leg - but we were running much higher pressures. Keep us posted....