Installing a ZX600 shock

1986 ZX600 Rear Shock Installation on a 2004 Ninja 250

This shock was $5 on eBay. (This was a while ago. As of April/May, 2006, not-too-rusty ones were going for $50-80 shipped.) Here are illustrated instructions on the installation. It shouldn't take more than an hour. (More notes at bottom of page).

Here's the shock. You'll need to take off all that bracketry surrounding the air valve. You should also check to see if it holds pressure before beginning the install. Be sure to see the instructions for checking air pressure at the bottom. Most ZX600 models need little or no air.

1. Put your bike on the centerstand. Take off the seat and remove the left side panel with a phillips screwdriver. Set the plastic away from your work area to avoid damage to it.

2. Optional: Remove the coolant reservoir using a 10mm socket on the two bolts. Zip-tie the reservoir out of the way (the frame towards the front works). Here's what you're looking at now...

3. With a 17mm socket, begin removing the upper shock mounting bolt. It threads into the frame, so there isn't a nut on the other side.

4. Now, remove the lower shock mounting bolt. The bolt head is 17mm but you'll need another socket/wrench to stop the nut from spinning with the bolt (nut = 19mm). An impact wrench (if you have one) will work wonders for this step.

5. The shock will now drop out (with a little persuasion). Put the nut back on the bolt and set it aside. Now you will need to remove the bolt to the left of lower shock mount. Again, use the impact wrench and set aside. This will aid in the positioning of the larger ZX600 shock.

With both shocks out, you can compare the two. The ZX is much wider and heavier, but slightly shorter.

6. Now you need to slide the ZX shock into position. This can be tricky. There is only one way the shock will sit correctly - the adjusting screw up top should be on the right - closer to the rear brake pedal. If it is reversed the screw will hit the frame and the shock will not align. Be careful not to harm the air line/connections. Insert the bolt (remember, there's no nut) and tighten it down.

7. Before attaching to lower shock mounting bolt, assemble the arms.

8. To mount the bottom end of the shock, first you need some 1/2" washers to act as spacers for the bolt. Without these, the shock will have too much side-to-side play. You may also find that the lower mounting bolt from the stock shock is too short. You can replace it with one from the ZX600 shock, part # 92002-1464 (BOLT,12X60). It is 5mm longer. (available from the usual OEM suppliers).

For the assembly to line up, you need to raise the rear wheel because the new shock is shorter than the old. A piece of 3/4" plywood and a 2x4 will help lift it. Once you work the bolt through, tighten down the nut.

9. Now, about that air hose: It can be zip-tied along the top of the swingarm, or anywhere else that the valve can be accessed. You will want and need to check pressure and adjust as necessary. View from below:

The view from above:

10. Now, double check the upper mount, lower mount, and rod assembly bolts, throw the coolant reservoir back on, reattach the side panel, pop on the seat, and you have a MUCH better rear suspension than stock.

Checking the pressure in the shock

Don't use an air compressor, and don't use a gauge. Get a shock pump from a bicycle store (this one is from Performance Bike, $20.)

The air reservoir can burst if you put too much pressure in it, and then you get to start all over again. Likewise, if you put a tire gauge on the air hose, some of the shock oil may leak out. It's better to get a good shock pump, like the one above, and use that to check and adjust your pressure.

Max psi is 28, so be careful. It doesn't take much to get that high. Make sure your bicycle shock pump is accurate at that low pressure. Several ~140-pound riders reported on their pressure settings. One on the "A" series ('85-'87) used about 15-20 psi. A different member with an "A" series said he uses about 5 psi around town, and increases it to 20 for sporting weekend rides. The member who had a newer "C" series ('88-'97) shock said that he usually found the shock to be stiff enough without any air in it. You'll have to test for yourself, and see what works for you. Be careful when adding air, though.

Notes:

• You can tell the difference the moment you sit on the saddle. It's much more stiff, with quicker rebound.
• Experiment with the settings. Customize it to your weight/riding style.
• 2-up riding is amazing compared to stock.
• The bike sits lower now, but there isn't as much sag while riding, so it ends up being about the same as the stock ride height.
• The centerstand is harder to use because the wheel is higher than before.

What you're looking for

You want a shock from a ZX600 A, B, or C (1985-1997). You don't want one from a ZX-6 (ZX600E) or a ZX-6R (ZX600F).
'85-'87 ZX600A and '87 ZX600B part # is 45014-1307. '88-'97 ZX600C is #45014-1367.

If it looks like this:

Or like this:

It won't fit.

It has to look like Fat Boy here: