This is what is in an air shock.
damper found in these types of suspension is nothing more than a piston, a cylinder, shaft, and eye to mount it.
*Look at the bottom (cylinder) of the cut-away damper and you will see an orifice. The diameter of the hole controls the slowing action. Thicker oil = smaller "hole" + more stiction (parasitic drag).
*Push the oil out and it resists due to the size of the hole for the volume being pushed out. Pull it apart and the damper resists the action because the oil is sucking through the orifice.
* In a stock air shock there are 2 springs, an inner and an outer. The white inverted cup is pushed down through air pressure. The cup in turn pushes down on the outer spring and puts more tension on it. This is called adding pre-load on an externally adjustable gas shock. A very small piston inside of a hollow cylinder and an air bag on top sucking the oil in and out a fixed hole is not an acceptable ride for the road for me.

Do not confuse a for real shock and the ride you get to a Progressive 440. Like a Lexus to a Yugo except the Ohlins is $150 cheaper than the Progressive 440 to HDF members. Different planets in contrast.

 

I added 5 lbs to my shock and it leaked all over at 2500 miles. luckily covered under warrenty. no prob since

 

Steve,
Some here (including me) would assume that changing the oil on the stock HD touring shocks
requires more than just draining the old oil out and refilling with the proper amount??
That's why we have never done it....or is it really that simple??
Bill

 

That's the key phrase in your statment, '...leaks OUT of a shock...'

Not ctiticizing, just asking... Isn't wobble a side to side motion? Shocks are there to dampen the up and down motion. How would bad shocks cause wobble?

BTW, my RK has over 67k on it now. I am fairly sure the shocks are original. I may be fooled from never having ridden on new shocks, but they seem to be working properly.

 

The Original Shocks were on this 2001 Sporty when bought it .. They worked fine but sold them for 40.00 and went with New Progressives...

 

Not that we were talking about Sporty shocks, but I got some old ones. My '77 still has the originals and they work just fine.

 

Great thread with some good advice, I will hit 40K on mine the next time it's out of the garage, right now I don't think I have any issues, but this winter I will check the shocks out.

 

I'd like to thank FastHarley for the 'exploded' view, and the great description. I've often been tempted to tear apart a shock even though I had a decent idea how they work.

I once saw a Yamahahahahaha! with what the owner said were cut-down shocks. I actually liked it's stance. He also stated that HE cut them down himself, but he couldn't be specific about his method. I took it into mind that he had just come out of a bar was a little wobbly before he got on his yammie.

 

By having uneven damping on each side, the shocks fight each other and could cause the swing arm to twist. Not a problem on a single shock set up. That's why it's so important to make sure you put the same amount of oil in each front fork. Put a board across 2 different springs and press down on it. it will sag lower on the weaker spring. Harley suspension isn't all that stable anyway. Why aggravate the situation. If oil isn't leaking out of the shock, then why would you replace it? I would think a worn out spring or air leak would be the problem in that case. You don't change car shock oil do you?

 

The problem with my shocks was that they didn't want to return after being compressed. They were holding the air pressure OK. And I didn't have any oil leaks. So even though the air pressure holds and you don't see oil leaking, you may still have bad shocks.

The biggest difference I noticed after putting mine on was when I ran over a slightly raised seam across the road. I now don't notice them much when before I felt like I needed to raise my butt off the seat as I crossed the seams in the road.