Marzocchi forks are famous for working for ages without fettling. However an oil change will make them run smoother and last longer. It's not difficult to do either. This service is being done on a Z150 fork but the Z1s are very similar as are some other Marzocchi forks.
- 21mm socket
- 12mm (deep and narrow) socket - check you have one that fits the bottom nuts before starting
- 10mm open ended spanner
- 2.5mm allen key
- Container for old oil
- 7.5wt oil (350cc or slightly less - see below)
- Teflon Grease
Remove the forks from the bike and give them a good external clean. Remove any air pre-load if you are using any.
2. Engage the ETA and compress the fork. Undo the small hex bolt and remove the rebound adjuster dial from the top of the right leg. Use a 21mm socket to undo the top cap on the right leg.
3. Hold the red lock nut under the top cap with a 10mm spanner and remove the top cap using the 21mm socket. Remove the washer that is under the top cap.
4. Remove the (yellow) spring.
5. Tip the fork over a suitable container and empty the oil from the right leg. Cycle the damper shaft to get the oil out of the damper.
6. Release the ETA and then remove the ETA knob. Repeat the above process for the left leg removing a shorter red spring and plastic spacer above it.
7. Undo the bottom nuts. You will need a socket that is thin enough to fit in the recess and deep enough to go over the dome on the nut. I had to get this hexagonal socket drilled out slightly to go over the dome. Hold the damper assemblies with your fingers to prevent them turning while you undo the nuts. Remove the damper assemblies and clean them.
8. You can't get the ETA assembly apart so stand it upright to allow any remaining oil to drain out. Gently unscrew the rebound adjuster rod from the rebound assembly. It has a fine thread and should unscrew by hand. Clean and stand the rebound assembly upright to drain too.
9. Seperate the stanchions from the lowers. They should slide apart easily. Give everything a good clean. Something to poke rags into the forks that won't scratch them is handy e.g. a bit of dowel. Either remove the springs from the seals (there's another hidden one on the internal oil seal too) or be careful not to dislodge them.
10. You should now have all these bits clean and ready for re-assembly. Start by applying some grease imbetween the inner oil seals and outer dust seals. Don't forget to replace the seal springs if you have removed them and then carefully slide the stanchions back into the lowers taking care not to damage the seals.
11. Slide the stanchions right down and then replace the damping assemblies. Tighten the bottom nuts to hold them in place. Don't over tighten them! 11Nm is the recommended torque if you have a torque wrench.
12. Fill both legs with the same amount of oil. The recommended volumes are listed below in cc.
|Z1 Free Ride
Put about a third of the oil in then cycle the damper to remove any air. Add the rest of the oil. Carefully re-insert the rebound adjuster rod and screw it in by hand.
13. Insert the springs, washers and spacer and re-attach the top caps. Use the 10mm spanner to hold the lock nuts and the 21mm socket on the top caps to do this.
14. Extend the fork and screw the top caps back into the stanchions. Replace the rebound and ETA dials. Put the forks back on the bike. Add any preload air. Adjust the rebound and try them out!