The only difference between the two motorcycles was the damping controls in the front forks. This will make the action much firmer when hitting the brakes, thereby controlling dive the front end compressing during braking. On his suggestion I also fitted a fork brace. The greater the resistance to flow is at the compression orifices smaller holes or thicker oil , the greater the potential for cavitation. It looks like I can do this over a weekend. They mimic the action of cartridge forks, which replace the holes in damper rods with valves that provide damping at low fork speeds, and open up to let oil through at high speeds, preventing hydraulic lock.
Notice that as the speed builds, the force builds. About a month ago I noticed I had a leaking left fork seal after a ride thru Joshua Tree nation park. The lap times were virtually identical between the two setups. Local mechanic reckons my front end was one of the best he had felt for some time. Just like on the compression stroke, rebound resistance on a damping rod fork is created through orifice damping. Pretty easy stuff and no special tools required. At the opposite extreme, the oil flows easily through the holes over small bumps, providing little or no damping.
When braking, the front end dives rather slowly in comparison to the high velocities created on an abrupt hit of a square-edged hole or rock at high vehicle speed. Unfortunately, not all bumps are rounded and small in size—when a square-edged or large bump is encountered, orifice damping can create a very harsh ride. Orifice-style damping increases very rapidly as velocity increases. In the past all that could be done to improve these forks was change spring rate, oil viscosity, or damping hole size until now. By increasing the valve spring preload, more pressure is required for valve opening. I had emulators placed in the front and gold valved the standard rear.
Rebound damping, however, is a much simpler job than compression damping. With the Emulator installed on top of the damping rod, low-speed damping is controlled by low-speed bleed hole s in the valve piston see figure 3. It can also travel out through the rebound hole s in chamber B, but this is a much smaller volume. Cartridge Emulators make damping rod style forks perform like well-tuned cartridge forks. Damping rod forks are notorious for being both too harsh and too easy to bottom. Simply put, damping is accomplished by fork oil flowing through holes as the fork compresses and extends.
I have ordered some new Race Tech springs and cartridge emulators from the states. The larger damping hole will be mushier, though it will be better at high speed. The oil pressure builds in chamber A and beneath the Emulator to a point that lifts the Emulator piston off its seat, allowing the oil to flow into chamber C see figure 3. Its no enduro bike, but damn you can push it! If motorcycles could be ordered like cars, with a long list of options and trim packages to choose from, odds are some current equipment would all but disappear from the motorcycling scene. At this point it looks like they need replaced.
This pressure in chamber C is dependent on the initial pressure, the compression ratio oil level , and the travel. Simply put; Emulators make damping rod forks perform like well-tuned cartridge forks. Rebound only has to control the force of the fork spring, whereas compression damping has to deal with whatever forces the road or track dish out. Once you understand cartridges, it will be easier to understand shocks. The fact that you have a cartridge system doesn't necessarily mean that it works well. I was planning to do it myself until I talk to the vendor that will be doing the work. If you understand damping rods and their limitations and solutions, it will be easier to understand cartridges.
I decided to take the Lee Park total control class. Cavitation is the formation of vapor bubbles in a flowing liquid caused by a decrease in pressure. In fact, when going through long duration dips or gullies—even if they are not very deep—the forks can bottom. They have to do all the suspension challenges of both road and off-road work by holes used to regulate the flow of fork oil. This means the wall thickness, not the outer diameter or inner diameter. However, the directions were amazingly logical.
This is not absolutely true, of course, but because the damping force becomes very high the maximum velocity the fork reaches, in practice, becomes limited. I'm duboius about many dealers giving me expert advice. Thus the limitations of orifice damping are less critical for rebound than for compression. This occurs specifically in areas where the pressure of the liquid falls below its vapor pressure. Damping rod forks are notorious for being both too harsh yet too easy to bottom.
The main spring supports the sprung mass of the front of the motorcycle and rider. Front and rear done by Terry Hayes out in western Sydney. For additional information, see the Global Shipping Program This amount includes applicable customs duties, taxes, brokerage and other fees. These forks were very inconsistent and wear became a big factor in how much rebound damping was created. I have replaced the rear mono with a fancy one from Elka Suspension in Canada.
I'm about to send my 650 forks out for emulators and tuning. Do Race Tech Gold Valve Cartridge Emulators work? Had Terry Hay from shock treatment do mine. Damping Rod style forks are notorious for being both too harsh, too mushy and too easy to bottom. These tunable valves sit on top of the damping rods and are held in place by the main springs. The emulators are adjustable so be prepared to fiddle around.