Home arrow Product Reviews arrow Engine & Exhaust Upgrades arrow Rekluse Z-Start Pro KLR650 Clutch

The Rekluse Motor Sports Z-Start Pro Automatic Clutch
for the KLR650 Review

Reviewed by The Patman
April 3, 2008


Information is available HERE from Rekluse Motor Sports.

The direct price from Rekluse Motorsports is $729.00 as of April 3, 2008


How many times have you seen a really neat product, maybe in a magazine, or even on the tellie, and think to yourself  “What a great idea”!  And of those great ideas, how many have you seen that actually work?  If your experiences are at all like mine, the really good products, the stuff that actually makes your heart beat a little faster, are sadly, few and far between. But every once in a while, something really cool comes along that actually works as advertised…read on.

For the past month or two I’ve been living with the latest offering from Rekluse Motor Sports company up in Boise Idaho. The Z-Start Pro Automatic Clutch for the KLR 650.
Some of you may know Rekluse for their past work in the field of automatic clutches. These fancy auto-clutches have proven very useful in the off road motorcycling world especially in Cross Country, Enduro and Desert events. So having a background in Cross Country racing myself, I’m certainly familiar with this type of unit, it’s competitors, and the benefits it offers to a competitive racer.   The question to us is:  Will something like this show the same usefulness in the Dual Sport and Adventure touring world?  The only way to answer this question of course is to install one of these things and giver ‘er a whirl.

The Rekluse Z-Start Pro Automatic clutch is a centrifugal pressure plate and center hub assembly that mounts inside your existing clutch basket, replacing your existing pressure plate, springs, and metal plates while retaining your existing friction plates and clutch release mechanism. It allows you to use your clutch as you would normally ( for the most part ), or as an automatic clutch like the one on your little sister’s 50cc scooter.


The kit comes packaged neatly in a nice box and includes everything you need from excellent instructions and diagrams, to installation and measuring tools, adjustment plates, and even a little tube of Lock-tite to keep everything where it’s supposed to be once installed. Oh and of course, the cool looking Rekluse stickers…if that’s your thing.



The installation is detailed, but fairly straight forward, and (due in no small part to the great instruction set), if ya have the tools ya need, you can start the project first thing in the morning and be riding by lunchtime.

Other than your basic tools and what’s included in the kit, you’ll need a torque wrench or two ( inch pounds and foot pounds ) a 30mm socket, and a corresponding breaker bar,  a screwdriver with interchangeable tips, and an air impact gun is useful as well. ( you might also take the opportunity to get a water pump seal kit, or at least the center impeller o-ring, and a new oil filter wouldn’t hurt either.)

The first thing ya do is read the instructions, and check out the pieces and parts. Then when you’re done, do it again. You’ll wanna spend an extra minute marveling at the superb workmanship that went into the parts in your kit. The hardware, component materials, and their coatings ( hard anodized ) are flawless, as is the machining. You won’t find anything cheap or ill fitting here. Very nice.  (Note: Though everything is packaged in plastic bags, I did find one steel washer that had a bit of surface rust on one side, it was handled quickly with some Scotch-brite. Perhaps just a little dab of oil or grease from the manufacturer will prevent this tiny anomaly in the future. Also a few of the parts are assembled for shipping only like the top plate, the pressure plate, and some small stuff like the retaining ring, at first I thought I was missing parts as the documentation doesn’t mention this. You’ll have to remove (and save) two screws to “unpack” these few parts).


This isn’t a difficult installation, but ya do have to pay attention, ‘cause the inside of your clutch housing is not a place to make a mistake, So make sure you read and understand the instructions again.

Once you understand how it all works and what goes where, the fun begins.
They suggest just laying the bike on it’s left side (on a stand of course) to ease installation and certainly you can save your oil this way as well. You may want to save your oil as you must change it after the quick break-in period. Laying the bike on it’s side makes it a bit easier to install the various parts and assemblies as gravity will lend you a hand.


The installation calls for the removal of your water pump, the clutch side cover, your clutch pressure plate, and your center hub. You’ll reuse the fiber plates and use the new Rekluse center hub, metal plates, springs and pressure plate assembly. Then reassemble it all with fresh coolant and oil. I’ve made a more detailed account including more photos, of the installation for the KLRWorld forms in the “how to” section. But I’m sure you’ll find, as I did, that the instructions are excellent.  Do pay special attention to the measurement of the pressure plate gap, they give you special tools to do this, and a proper gap and a proper idle setting is necessary to proper operation. Also I should mention that unlike some other automatic clutches, this unit requires no modifications that would keep you from putting the old unit back in if the need ever arises.

After you’ve finished up with the installation, which will take a couple of hours if you’re careful, comes the break-in and try out period…it will make you smile whether you want to or not.

Ride Prep & Clutch Theory

Before I talk about what this baby’s like in action, let me discuss briefly how a clutch works.
Basically you have two rotating parts, an smaller inner hub and a larger outer basket, one connected to the transmission and the other connected to the engine, but not to each other. The hub sits inside the basket with about ¾ of an inch separating the two. They do both spin on the same axis, one on a shaft and the other around the shaft, but just on a bearing.  The space between the two is where a stack of alternating plates, some metal, some fiber, will rest. There are metal plates generally 6-9 of them that are toothed on the inside to mesh with the teeth on the center hub. These metal plates are smooth on the outside and can’t contact the outer basket. They turn when the hub turns. There are also 6-9 fiber plates that are toothed on the outside to mesh with the outer rotating unit, the basket. These fiber plates are smooth on the inside edge so as not to contact the inner hub. They turn when the basket turns. So the alternating stack of metal and fiber “friction plates” are each locked to their own hub (inner or outer) but not to each other. The springs in the clutch are used to force the outermost pressure plate into the metal and fiber friction plates, and squeeze them to the point that the plates connected to the outer basket, and the plates connected to the center hub, lock up, and both hubs start turning together. Since one is geared to the engine, and the other to the transmission the bike moves forward.  When you release pressure from the pressure plate (by pulling the clutch cable) the metal and fiber plates once again slip, and once again neither hub is connected to the other and the bike stops moving.


On your manual clutch, the springs hold the pressure plate against the friction plates all the time, until you pull the cable, pulling the pressure plate away from the friction plates and causing them to “slip”.  So it’s always engaged, until you pull the clutch lever.
On the centrifugal or automatic clutch, spring pressure hold the pressure plate assembly away from the friction plates all the time so it’s always free or disengaged, until the engine is revved and the pressure plate is forced inward onto the friction plates, squeezing them tight and making the bike roll.

So what makes the centrifugal pressure plate work you ask? Well I’m gonna tell ya.
Ya got two plates that as an assembly makes up the new pressure plate. The inner plate has radial slots around it’s perimeter that heavy tungsten balls sit in. Each slot is deeper toward the middle or inside of the plate and shallower toward the outside edge. This plate is the one that contacts the friction plates, and has holes in it to allow it to move in and out freely on the ten center hub posts. It sits atop of a spring to keep it away from the plates when the clutch is disengaged.
Another plate sits on top of this one and unlike the inner plate is not free to move, and is bolted solid to the same ten posts that stick through the inner plate. With me so far?
OK, so the heavy balls are sandwiched between these two plates, the outer plate, which can’t move, and the inner plate with the grooves (deeper in the middle shallower toward the edge). 
When the clutch isn’t spinning (engine at idle), the balls tend to roll down to the deeper center section of their grooves, and as the groove is deeper there the balls don’t take up as much space between the plates (they sit down in the grove), and the spring that this plate sits on, tends to push the inner (movable) plate outwards, away from the friction plates, and the clutch disengages.

As engine speed picks up, the balls are thrown outward into the part of the groove or slot that isn’t as deep. As they roll outward, they rise up out of the slot as it gets shallower.  In doing so the balls now force the plates apart. Since the outer plate can’t move, the inner plate is then forced against the friction plates and the clutch engages, and the bike goes.

In manual use, you pull the clutch lever, and the entire center hub, the ten posts, the pressure plate and everything is pulled away from the friction plates, and once again the clutch is disengaged.


Anyway, on to the break-in and test rides.

Ride Report 

Starting the bike is done in the normal fashion, (make sure its in neutral) with the normal warm-up period. Check your idle speed, too high and the bike will creep forward, too low…and it will be…uh…too low.
This is also when you'll make the clutch cable adjustment. Ya see, your manual clutch was adjusted to about 1/8th of an inch free play when it was engaged...which was all the time, the Z-Start Pro also needs about 1/8 th of an inch free play when it's engaged...but that's not until the engine is reved. So after ya get it warmed up the final adjustment is to rev the engine to about 4000 rpm so the auto clutch is engaged, and at that point adjust the cable in the normal fashion. It'll feel loose at idle, and it will tighten up to feel pretty normal as the engine revs up. It's all in the instructions.

Then, following the directions simply put your bike in gear (with or without clutch use) then slowly accelerate (without the use of the clutch of course).

Certainly we all hold our breath during the first start-up after a project like this one, but I assure you, if you completed the installation and set-up properly you’ll soon be amazed at how smoothly and effortlessly the bike pulls away from a stop.  The clutch uses exactly the right amount of “slip” for the load and the speed of the engine to give you perfect engagement every time. No lugging, no over revving. The Z Start pro seems to start pulling the bike at about 1400 rpm in my case, and seems to disengage at about 1150- 1250 rpm. This is not in any way dependent on ground speed but instead on engine rpm.

The break-in instructions will tell you exactly how to accelerate and decelerate several times to polish up the ball-grooves, and thus complete the break-in.

I’ll admit that normal around town riding took a bit of getting used to at first, and there are just a couple of things to keep in mind while using the Rekluse Z-Start Pro.
First, remember that the bike will now start while in gear, and if you, like so many of us, has disabled your clutch safety switch, it will not only start while in gear, but do so without you even touching the bike ( other than the starter of course ).  So, make sure you’re in neutral, if you’re the type to start the bike and walk away to let it warm up.
If you’re not in neutral, and reach over to “rev it up”…it will roll away, and you’ll look like a squid.
 It does however allow you to do some stuff you couldn’t do before, at least not as easily.
For instance, when in first gear at a stop, of course you can just drive away with the throttle, it seems to start moving at about 1400 rpm. When you hit the brakes and the engine slows to around idle speed, the clutch disengages. This means that no matter how ham fisted you may be, you just about cannot stall the motorcycle.
This also means that even if you come to  a stop in second or even third gear, not only will the bike not stall, but when you hit the gas to take off, the bike will go. The clutch will feed the right amount of power to the back wheel to start off in third gear. Now of course this isn’t good for the clutch any more than it was with the stock unit, but the point is, the Z-Start pro can handle it, and pretty smoothly at that.

In heavy traffic the unit is a joy, pop it in first gear and just drive with the throttle.

Out on the road you wont notice much difference from your stock clutch unit. If you’re the type who shifts without using the clutch lever, then you may not notice anything at all. No weird noises, no lurches… in road use, it’s kinda transparent.  Certainly you have to keep it in the right gear for your circumstance, but the clutch part is handled. Remember, you can use it if ya want ( to smoke your tires for instance ) or not. I still use it for the first to second gear change ( my KLR has a rough 1st to 2nd shift anyway ).

Dual sporting and adventure touring is all about being versatile, and going anywhere, so I had to get some trail time in on this test as well.  The trails are where this baby can really shine. We all know things can get complicated pretty quickly when you try to get a 450 pound bike through the sand and mud, up and down the hills and through the tight trails. Having one less thing to worry about, and having that thing work better on it’s own than you could work it anyway is a blessing.

In sand and mud it seems to take off without the digging of trenches that is often the case with lots of clutch slippage and a heavy throttle hand. Traction with a big fourstroke and an automatic clutch like the Z-Start Pro especially in slippery off camber stuff is just excellent.

On hills, you’ll find that traction is equally abundant on most grades, and once again if you come to a stop, the clutch won’t let the bike stall, or at least you can restart in gear. If the incline is such that you need lots of engine rpm and slow forward speed you can still use the clutch manually to rev the engine higher and slip the clutch slower.
There was some public concern about the loss of engine braking on descents when using an auto clutch of this type, but I’ve found that downhill engine braking still exists as long as the engine is turning at an rpm that is above idle or the disengagement range. For example, on a steep down hill in second gear the engine would slow the bike normally until one of three things happened, a) the bike slows to the point that the engine is at idle, or b) you apply the rear brake hard enough to lock up the wheel, which will allow the engine to drop to idle, or c) you manually pull the clutch lever and allow the engine rpm to drop to idle.   Remember, when the engine goes to idle rpm, the clutch is disengaged and you’re coasting. To recover from the situation, simply downshift to first and give the throttle a quick “blip” this will bring the engine above idle and the clutch will re-engage and start the engine braking all over again in first gear. And the same is true for any situation where you’re freewheeling and need the clutch to engage, just blip the throttle the slightest bit to bring the engine above idle and the clutch will take over from there.

On tight trails it’s really fun ( as much as a big dual sport can be anyway ) because of the ability to allow you to slam the brakes into a corner and not kill the engine, then blast the gas without the use of the clutch lever to get down the next straight section. And unlike some of it’s competitors the Z-Start pro allows use of the clutch to wheelie over a ditch or log as is necessary.

Here’s a short demo video that I did so you can see all this in action elsewhere on this page.

If you are having trouble viewing this video using Firefox, you'll need to download and install this Firefox Plugin located HERE.


I’ve had this unit for a couple of months now and have found no fault with it whatsoever…a couple of quirks perhaps but these are inherent to the design of an automatic clutch, and not a manufacturing or quality issue.

One quirk is the fact that you have to remember not to blip the throttle while in gear at a traffic light, another is getting used to applying a little throttle to re-engage the clutch for downhill engine braking, and the only other issue ( which I never experienced ) is that with this clutch installed, they’ll be no push starting. Since the clutch is installed on the engine side of the transmission all the pushing you can muster won’t engage it. Now this isn’t a problem for those of us who keep the battery and starting system in good shape, and in 4 years of ownership of the KLR is has never required a push start. I asked the manufacturer about this, and the fix ( for emergencies ) is to carry an extra clutch plate with you. If you have no alternative other than a push start, tilt the bike over, install the extra plate and the bike will act like it has a manual clutch again. Not the simplest thing, but certainly a rare occasion, but you wont be left “dead in the water”. This is no different than the automatic transmission in the family car though and we seem to get along with those just fine.

Rating the Rekluse Z-Start Pro Automatic clutch for this review is pretty simple. First thing a lot of us look at is cost. And this baby aint cheap. But it's not built cheap either, and this is a mod that will change everything about your power delivery and the way you use it. This is a big deal. It carries a price of a little over $700 from the Rekluse web site.  So, for that price is it worth it? Does it do what they say it will? The answer is yes. Is it well built with no gimmicks or BS? Is it reliable in a variety of riding situations? Again the answer is certainly “yes”. Straightforward install? Well-written instructions? Good support from the factory? All positive. Not to mention that this unit has been accepted and proven on the racing circuits world over. Not to mention the pounding my 705cc KLR has given it over the past few months.

My only concern, and I know it’s pretty farfetched in this day and age, is the inability to push start the bike when my battery dies in someplace like Peru. If you’re bike is equipped with a kickstart lever, then it’s a non issue, but something I have to mention in an honest review. 
I saved my old clutch parts and could reinstall them in a couple of hours, ( this isn’t anything you can’t undo )  but I think I’ll keep this baby right where it is and take my chances with the push start thing. I'll just carry jumper cables.


Normally I’d have to say 10 out of 10, the device does exactly what the manufacturer says it does, but because this device is marketed for a dual sport bike that can take you anywhere in the world, the loss of the push-start option decreases it’s score by a half a point.

Rating : 9.5  out  of  10


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