What is it?
The z-Start Clutch is a retrofit automatic clutch. It works
using centrifugal force to automatically and smoothly engage the clutch just by
using the throttle. The z-Start manages the clutch function so the rider can
focus on riding and having more fun.
What is included with the z-Start Clutch?
The main portion of the z-Start is the clutch assembly. The clutch assembly
consists of a lower assembly that bolts directly to the bike’s center
clutch. The ball-ramp pressure plate with balls and a top plate then mounts to
the lower assembly. The z-Start Clutch includes a throw-out assembly to allow
the auto-clutch to be disengaged. There also a set of steel drive plates to
enable adjustment of the clutch pack height. There is usually a thicker gasket
to provide some additional clearance for the z-Start. Everything except basic
tools and two sets of feeler gauges are provided in the kit to complete the
What is the z-Start made from?
The z-Start Clutch is made from the highest quality billet 6061-T6 aluminum and
billet 4140 steel, precision CNC machined to tolerances of .001" (that's one
one-thousandth of an inch).
How does it
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
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
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
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
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
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
Does the z-Start Clutch require me to modify my existing
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
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.
Is it for me?
I'm new to dirt bike riding. How can the z-Start Clutch
Riding with the z-Start Clutch removes the frustrations of clutch
control and stalling that many new riders face. Working the clutch smoothly,
especially at lower speeds or on hills is challenging for experienced riders.
The z-Start Clutch manages the clutch operation perfectly so you can just focus
on the fun of the ride!
I'm a pro-level motocross & supermoto racer. How can the
z-Start Clutch help me?
With proper tuning of the z-Start Clutch for track conditions, most
riders will be consistently faster off the starting line with a "roll-on" start
than by "feathering" the clutch off the line. The z-Start Clutch allows the
rider to forget about the clutch lever for most racing situations and focus on
the track in front of the rider. Without the need to reach for the clutch lever
during braking, over jumps and out of corners, fatigue is greatly reduced and
control is improved. With a high engagement point, corner exit speed is
typically better because the z-Start "feathers" the clutch perfectly every time.
The z-Start is virtually stall-proof and even after a crash, most bikes can be
picked up and ridden away quickly without fear of stalling.
I race cross-country events. How can the z-Start Clutch
In technical trail sections, the z-Start Clutch really shines. Forget
about the using the clutch lever to negotiate slow, technical sections and focus
completely on the trail in front of you without fear of stalling and precise
control of speed and power to the ground. For technical hill climbing, the
z-Start Clutch allows you to back off the throttle to negotiate obstacles and
then reaccelerate without fear of stalling the engine or "looping-out". Most
riders can attack corners more aggressively by brake sliding into the corner and
then accelerating without the need for delicate clutch work or a gear shift;
reducing physical and mental fatigue on the rider. The z-Start Clutch is
virtually stall proof and even after a crash, most bikes can be picked up and
ridden away quickly without fear of stalling.
I'm an experienced trail rider. How can the z-Start help
Riding with the z-Start Clutch makes every ride more enjoyable. Without
the need to manipulate the clutch lever, the rider has less fatigue and the bike
is considerably more forgiving in almost all situations. The z-Start Clutch can
reduce the stress and anxiety of traversing technical sections of trail or
difficult hill climbs. The z-Start Clutch adds trials-bike like control to
motocross bikes and trail bikes alike; allowing the rider to take a whole new
approach to sections of trail most riders struggle through.
What if I
What kind of warranty does the z-Start come with?
The z-Start Clutch is backed by a 1-year warranty from defects in material or
workmanship on all Rekluse manufactured parts. The z-Start Clutch also includes
a 30-day money back guarantee. If for any reason you are unhappy with how the
z-Start Clutch performs in the first 30 days of use, simply contact Rekluse or
our dealer for a return authorization and we will gladly refund your purchase.