I am looking into seriously getting the Z-Strat clutch for the bike. I think this might make a big enough difference that I could do longer stretches or maybe even race. There was a story floating around that someone smoked there clutch running one of these in the mud for a long run. Can someone tell me the story behind that?

Was the ball weight to light? Does anyone run one and have the steup that works best? Does the cluch disingage going down hill? Is there still engine braking? I know you can't bump start it but, I heard both that it disangages with no engine braking and that there is engine braking.

This is the left wrist I have to work with: http://www.borynack.com/Bruce/Video/Finished1.JPG

I don't have a lot of use out of it but, if I didn't have to use the clutch I might be able to hold on to the bike a little longer.

Hey, I uh think yer missin some parts there...

Its stands to reason that you would have some engine braking until the engine rpm dropped low enough for the clutch to disengage, kinda like a CT90. As far as burning it up, its possible the person who did it was bogging down in the mud and the clutch wasnt grabbing. If it was a big thumper and/or geared tall, the healthy low-end would really aggravate the situation.

A while back there was a thread about how the Z-start was setup to not slip when lugged. I was hoping to stire that back up so I didn't have to reinvent the wheel. I read the thread back then and thought cool but, didn't think I would spend the money and get one. Well, my left wrist sucks. I will still have the cluch leaver, I got that doohickey so I can still have it. Now I have one and whish I would have listened.

This is the reason I need one this is my left wrist: The Ulna bone cut in the clear and the carpal bones fused.

PM Qadsan about this. I know he did an extensive write-up last year about these.

Hey man I own one and it is great. If the clutch is in good shape at the time of install and you get your tolerences correct there should be no problem. I also have the Baja Designs electric starter so the no bumpstarting is a non issue with me.

Some one else will have to help you concerning it's dependability in mud racing. I ride moutain trails mostly with mud here and there with no problem. I lug in lower gears most of the time. No problems.

I PM'd Qadsan about this. But, he is not around....I hope he is ok! He did a write-up about the ball weight and all kinds of stuff. I was hoping he would chime in so, I would not have to cover ground that he already mastered :cry:

I know he has some health issues and I hope he is ok, it is not like him to miss a post!

Hi Bruce,

I sent you a PM the other day, but it gave me an error saying the PM was too long. I shortened it and sent it again without errors, but perhaps, it got lost in cyberspace (or user error on my part :cry: ).

It's one of the koolest products I've used in the last 30+ years. With the clutch perch option, the clutch lever pull is wayyy lighter than stock. You'll also find yourself shifting less often, which means less clutch work, so the combo of less clutch work and an easier clutch lever pull should make things much easier on the left wrist.

I have mine setup to lock up quick & hard, but my z-start is a gen 2. This is done by using the lightest spring in the clutch perch option and 18 tungsten carbide balls with the rest being steel. The gen 3's use fewer balls, but they are larger (more mass) and from what I understand, the stock config with steel balls is supposed to provide the same characteristics as a gen 2 with 18 tungsten carbide balls.

I have full engine braking down the steepest of hills as long as my rear tire is turning. If you fall near the top of a steep hill, be careful picking up your bike because if the engine is not running, it will act like it's in neutral and will want to roll down the hill as soon as you lift it (been there done it :cry: ). I really do miss the bump starting, but like anything, every product has its set of tradeoffs and I like the z-start too much to give it up. As for clutch slipping issues, the z-start actually provides more clamping pressure than the stock clutch at higher engine RPM, so there's less chance for slip, but this is a product that can be easily abused. For instance, taking off from a dead start in 3rd or 4th gear will drastically shorten the life of the clutch, but the z-start will allow you to do it pretty effortlessly. You just have to ride with common sense and it will last a very long time. I don't recall the exact numbers anymore, but I had worked out points in the RPM range where the z-start locked up so I knew how fast I should be going in each gear to minimize clutch slip. With the stock gearing, I recall 3rd gear being something like 18 MPH, so if you were going 18+ MPH with stock gearing, then the z-start was locked up with no slip.

When riding aggressively and when you’re between gears to where you want to feather the clutch to keep the power at or near peak without shifting down, the z-start will easily, elegantly & automatically handle this task for you so you can fully concentrate on riding without worrying about using the clutch lever. Some guys might say the xr650r pulls plenty well in all gears and they never have to shift, etc, but if you’re riding on the edge as I’m sure you do, then you know the bike is more exciting & pulls harder at certain points in the RPM range based on your gearing, engine load / terrain, etc. If I was racing friends through a narrow twisty sand wash with short straights, I’d be shifting down in the sharper turns to keep my engine RPM up and shifting back up in the straights. If the turn was a bit of a sweeper, then I’d probably be feathering the clutch a bit to keep my RPM up if I was to loose any speed. If the wash was a few miles long with lots of sharp turns, I may be shifting quite a bit and my clutch lever may get a good workout along with my left arm getting pumped. With the z-start, I can keep my bike in 3rd through many of the turns even if they’re sharp because the z-start is managing the clutch for me and feathering it when necessary (lower engine RPM). All I have to do is mange the throttle, brakes, body position and hang on. I can sometimes go deeper into a turn with more speed by using the brakes harder without worrying about stalling the bike, because the z-start prevents your bike from stalling if its properly setup. Brake slides are more productive for me because I don’t have to worry about stalling the bike even if I keep the rear wheel locked from 3rd WOT to a complete sideways stop.

Casual trail riding with the z-start is a blast, especially in the tighter single track stuff. If the trails are pretty tight to where you’re riding mostly in 1st or 2nd gear, you won’t have to worry about shifting because the bike will handle most everything from a crawl to WOT in 2nd gear and you can start and stop quite often without ever using the clutch lever or shifting. If you’re riding lots of open places, you can pretty much leave your bike in 4th or 5th gear unless you’re slowing down quite a bit. The z-start doesn’t make your bike completely automatic, but it does make it kind of semi automatic in some circumstances and it really cut down on my shifting & clutch lever use.

Installation is also a piece of cake. After you’ve installed one, you can install it in less than 20 minutes on future bikes. The first time always take a while because of the learning curve, but they’re super easy to install, especially now with the gen 3’s because they don’t require all the precise shimming of the gen 1’s & 2’s that I’ve used in the past.

Here's one of my previous posts on the z-start. Don't forget it comes with a 30 day money back guarantee, so if you do get one, ring it out good within 30 days, but I'll bet you end up keeping it :cry:

The z-Start simply uses the stock clutch friction & drive plates, so nothing is changed there. The only thing different is the pressure plate, which engages or disengages the clutch. Instead of only using the left hand clutch lever to engage/disengage the clutch pack, the z-Start uses inertia from the spinning engine to engage/disengage the stock clutch plates via the z-Start pressure plate. At idle, the z-Start pressure plate is pulled away from the stock clutch plates so it won't drive them just as if you pulled your clutch lever in. As the engine spins up, the z-Start pressure plate clamps the stock clutch plates together just as if you let out the clutch. The z-Start pressure plate has steel and or tungsten carbide balls seated in their own ramped slots. At idle, a spring plate keeps these balls seated, but when the engine spins up, these balls are forced outward up their ramps and they overcome the spring plate pressure, which in turns clamps the friction discs & drive plates. The clamping pressure increases with engine RPM, but the z-Starts provides an engineered maximum amount of clamping pressure through its ball/ramp design where as some other autoclutch products have no limits on their clamping pressure. Having more clamping pressure is great up to a point, but more isn't always better. If the rear wheel happens to be spinning wildly due to a loss of traction and then all of a sudden hooks up, that force has to go somewhere (rear wheel >> clutch >> gearbox). If the clutch was clamped tight enough, then your gearbox will absorb that energy and I'd much rather have my clutch slip a bit, which is one of several reasons I like the z-Start over other similar products.

BWB, I sent you a long PM yesterday also but I'm not seeing it in my sent folder. Did you receive a PM from me?


I also sent you a P.M.

Hope you received it


I did not get Ricky Racers PM! but, the others I recieved and thanked and so forth. What a great write up!!!!!! :cry: I didn't know but, suspected that there must have been a change. Iremembered most of the ball thing and you changing them and doing tests and all that is left out of the info on the Z-start so, I had to get to the bottom of it. Sounds like you are saying they went with your recomendations for the newer Z-start and the rest is by clearance. This makes me "feel" alot better about setting it up. I was thinking messing with balls and clearance and didn't want to be messing with the balls if you had already been there done that. Now I know that I don't have to mess with my balls to get going. :cry:

They still use balls on ramps to actuate the pressure plate (very simple operation), but the gen 3 product uses drive plates of different thicknesses to set the correct clearances instead of placing small shims on the clutch lower assembly (gen 2). The gen 2's also have a friction disc riveted to the pressure plate and the gen 3's don't. Changing out the drive plates to get correct clearances is much more user friendly as opposed to dealing with the shims, which had a chance of falling into the engine if you weren't careful :cry:. I'm still running gen 2's, but someday I'll update to the gen 3 product.

Here's the z-start XR650R manual you can download so you can get a better idea of what it looks like, how its installed, etc.


Here's the manual for the clutch perch option.


There's now a seperate break in manual.


The reason I have been away is I have been messing with my new Z-clutch and the perch dohicky. Thanks for all the help! :cry: I have a lot of reading and wrenching to do. I have to get ready to do a few suspensions....it's strating to pile up :cry:

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