Slipper Clutches

The z-Start Clutch is a centrifugal clutch that uses ball bearings to engage the clutch. The clutch provides a pressure plate with ball ramps. At idle the balls are at the bottom of the ramps and the pressure plate is disengaged. As the rider increases RPM, the balls move out the ramps, push on the Rekluse top plate and force the pressure plate into the clutch pack engaging the clutch. As RPM’s build, the balls continue to move out fully engaging the clutch. When engine RPM’s are reduced the balls drop back down the ramps and the clutch disengages. The take-off is smooth–as if you had perfectly feathered the clutch every time. The disengagement is quick eliminating any stalls.

At what RPM does the z-Start Clutch engage?
The z-Start is fully adjustable so the rider can set the RPM engagement point. Springs are used to provide back pressure to the clutch and disengage it at idle. It takes a certain amount of force to overcome the spring and engage the clutch. By changing springs and spring compression rates, the rider can easily set the RPM engagement point.

For example, a light spring can be easily overcome at a low RPM so the balls generate enough force to compress the spring and engage the clutch. This provides a hard engagement at a low RPM which is ideal for enduro riding. A heavy spring requires more force to compress so it takes higher RPM to compress the spring and engage the clutch. This provides a soft engagement with some clutch slip which is ideal for track riding, allowing riders to brake slide into corners and accelerate out of them faster with better traction control.

Does the z-Start require me to modify my existing clutch parts?
No. The z-Start Clutch simply replaces your stock pressure plate. No need to take apart the right side of your engine to get the whole clutch out. No need to send your parts away for permanent modification or to modify your existing clutch parts. With the Rekluse z-Start Clutch, you can always return any bike to a stock configuration.

Can the clutch lever still be used?
The z-Start Clutch is provided in a fully automatic mode. The z-Start Clutch on cable clutch bikes can be operated in a semi-automatic mode by adding the Rekluse Perch Adjuster. With the Rekluse Perch Adjuster, the clutch lever can be retained to override the auto-clutch just like the stock clutch lever does.

Hydraulic clutch bikes, like a KTM, do not need to add a Rekluse Perch Adjuster and can be configured in either fully automatic or semi-automatic mode.

What is the Rekluse Perch Adjuster?
The Rekluse Perch Adjuster is a device which mounts inline with the clutch cable and mounts into the stock clutch perch. The Rekluse Perch Adjuster provides two main benefits. Installing the Rekluse Perch Adjuster allows the rider to retain the clutch lever and provides the ability to override the z-Start Clutch. Additionally, the Rekluse Perch Adjuster allows the rider to adjust the engagement point of the z-Start Clutch. Two spring options are provided to allow for different engagement points. The Rekluse Perch Adjuster is also threaded to allow additional spring compression and therefore further engagement adjustment.

How difficult is the z-Start Clutch to install?
Riders who regularly perform maintenance on their clutch components can easily install a z-Start Clutch. Most people will spend 1 to 2 hours to read through the manual completely and carefully install the z-Start. After the first installation, subsequent installations after can be completed in 30 minutes to an hour.

Does the z-Start Clutch require me to modify my existing clutch parts?
No. The z-Start Clutch simply replaces your stock pressure plate. No need to take apart the right side of your engine to get the whole clutch out. No need to send your parts away for permanent modification or to modify your existing clutch parts. Rekluse always provides the ability to return any bike to a stock configuration.

Will the z-Start Clutch wear my clutch plates faster?
That depends on how you use or abuse the z-Start Clutch. With the z-Start Clutch, you will find that you are able to ride smoothly in one or even two gears higher than you normally ride. However, riding uphill, in 4th gear at 10mph for extended period of times will cause significant clutch slipping, accelerate clutch plate wear and possibly damage your engine. When riding with any automatic clutch, it is important to select the right gear for the situation. In general, it is safe to ride one gear higher than the riding conditions dictate for short periods of time. That being said, when used properly the z-Start Clutch should allow for clutch plate life equal to or better than a stock clutch.

What kind of maintenance does the z-Start Clutch require?
The z-Start Clutch is designed to work with a specific ‘installed gap”. The installed gap is the distance between the pressure plate and clutch pack when the bike is off. The installed gap is based on the distance that the balls rise in the ball ramps as the pressure plate is engaged. If the installed gap is too small, the pressure plate is too close and will cause the bike to drag at idle. If the installed gap is too large, the pressure plate cannot fully clamp the clutch pack and the clutch will slip excessively.

In order for proper operation and to maintain the life of the clutch pack, the installed gap must be kept in the prescribed range. Initially, the installed gap must be checked after breaking in the z-Start Clutch for twenty minutes. As clutch wear occurs, the installed gap needs to be checked at regular intervals. Rekluse ends riders check the installed gap after every 25 hours of riding.

How much weight does the z-Start Clutch add to my bike?
Installing the z-Start Clutch adds less than 6 ounces of rotating mass in the clutch. Keep in mind that the clutch spins at approximately 1/3 engine speed so flywheel effect of the z-Start is minimal.