Emulators
by Dickbender (Darcy)
Firstly, I am in no way associated with Race Tech.
Secondly, this task is reasonably difficult if you are not an experienced DIY mechanic then get a professional to do the job.
Now a little bit of theory. What is a Gold Valve Emulator and how does it work? The best answer for this question is from Race Tech FAQs
Q: I have a bike with damping rod type forks. I have heard that Gold Valve® Cartridge Emulators® are the greatest thing since sliced bread. Why?
A: Old fashioned damping rods while inexpensive to manufacture have major limitations. To create compression damping, oil is shoved through a hole or holes. Shoving oil through holes creates very little resistance to flow at low vertical wheel velocities as when hitting a dip or gully or applying the front brakes. This allows the forks to shoot through the travel fairly easily, diving or bottoming in these situations. On the other hand when the wheel hits something square edge, especially at speed, it needs a lot of oil to pass through the damping holes very quickly. Unfortunately the nature of shoving oil through holes is that as the wheel velocity increases the damping force increases with the square of the velocity. In other words if you double the velocity you get four times the force. This means the hole basically "hydraulic locks" resulting in a harsh spike. Damping rods give the worst of both worlds, they are both too mushy and too harsh at the same time.
An Emulator® is a valve that sits on top of the damping rod and is held in place with the main spring. To install them we simply remove the damping rods and drill out the existing compression damping holes so they are so large they do not create any appreciable damping. Then during reassembly we simply drop the Emulator® on top of the damping rod. The Emulator® creates the compression damping of a state-of-the-art cartridge fork. The ride is both firmer and plusher than the damping rod and is completely tuneable. Sliced bread is good, Emulators® are better.
If you got through that then your ready to move on.
Tools and Equipment
1. Bike lifter I have is the ATV lifter. Maybe a centrestand would work I don’t know for sure.
2. Racetech cartridge emulators p/n FEGV S4101
3. You also need some spacers made to adapt the emulators to the damping tube I used aluminium 33 mm OD x 27 mm ID 6 mm long. (I also had a pair 12mm long made)
Spacers
4. 5/16” drill and a bench press (a power drill would do in a pinch).
5. Hand tools including torque wrench, Allen wrenches and a good set of sockets.
6. Fork oil. I used 10W Shell. After fitting emulators the viscosity of the fork oil controls rebound damping.
7. Kerosene.
8. Rags.
9. Springs (talk to Race Tech) or at the very least, some longer preload spacers, if you don’t buy new springs.
10. New washers for bottom bolt.
Procedure
1. After you have all your tools and equipment set up, get the bike up on the lifter and secure it with a tie down.
2. Remove front brake calliper (secure with a bungy or rope so it doesn’t hang on the hose) then remove the front wheel, mudguard (fender) and speedo cable from the drive
3. Loosen the top bolts that clamp the forks into the top yoke.
4. Loosen the fork caps.
5. Remove the fork assemblies.
6. Loosen the bottom bolt from the fork assembly with either a rattle gun or clamping the bottom fork leg into a vice with towel around it.
7. Remove the fork caps and springs/washers/spacer tubes and tip the old oil out into a container.
8. Remove the bottom bolt the damper tube and top out spring will come out now. There is no need to separate the inner and outer legs unless you need to replace the seals.
9. Wash it all with kerosene and let it dry.
10. Mark and drill 6 x 5/16” holes in the damper tubes as per enclosed instructions
Stock Damper Tubes
Drilled Damper Tubes
11. Install damper tube into bottom leg, don’t forget top out spring and new washer.
Assembly
12. Fit the forks onto the bike (you might need some WD40 on the headlamp bracket rubbers) and remove handle bars cover tank or remove as well. This makes it easier to fit the caps.
13. Pour a little oil in the forks about 50-100 ml (so things are not dry).
14. Install spacer, emulator and spring then the caps.
15. Check/adjust sag as per instructions.
16. Remove springs
17. Fill with oil to recommended level 120 mm from top with fork compressed and spacer and emulator installed but no spring. Pumping slowly up and down until all air is out you will hear it.
18. Refit spring and fork cap.
19. Bolt all the other bits on mudguard/wheel then brake.
20. Check all bolts for correct tension including the damper tube bolts
21. Check the brakes by pumping a few times.
22. Go for a ride look for bumps to run over not go around.
23. Come home and drink some beer.
Top: Stock Spring
Bottom: Ikon Spring
08-18-2007 01:47 PM
