Z start gap - engagement point

19 replies to this topic
  • tool

Posted May 24, 2004 - 02:55 PM


i was wondering if you can change the engagement point on the z start by tightening up the installed gap? my gap is .96 mm. it doesnt fully engage fast enough, though it fully engages at about 4-5k rpm. the bike gets a little hot.
maybe i should try a gap thats tighter than .76 mm?

  • rbm33

Posted May 24, 2004 - 03:14 PM


im not sure about that. do you not have the adjustable perch? iv got the perch and it works great, iv got it dialed in to just about 100 rpm above idol.

  • tool

Posted May 25, 2004 - 01:50 PM


i dont have the adjustable perch. im using the light spring adjusted about half way out. but i was thinkin i should just get the perch, since its real easy to kill the engine with the brake. is that normal?
then maybe i could drop the engagment point and just pull the lever in when im on the brakes hard.
rbm, how does that overide perch work? if theres a cable on the arm... where does the spring go, on the lever?

  • rorhound

Posted May 25, 2004 - 02:25 PM


I'm not rbm, but I slept in at a Holiday Inn Express last night.

I have the perch and it is easy to install and adjust. The stock cable is used as is the stock cable adjuster on the bars. Added to the cable, between the end of the cable and the cable adjuster, is a housing for the spring (comes with a light and heavy spring, you make the choice), an adjuster for compressing the spring for differant engagement speeds, an insert that goes inside the spring and a rubber boot for the cable to keep the crud out.

I use the heavy spring in mine and just adjust it for trail or track. Stalling is a thing of the past.

When pulled, the bar lever still disengages the clutch for the starting gate if needed.

If you get it, just reassemble the cable assembly back to stock on the engine then install the perch adjuster on the bars.

  • lipskid

Posted May 25, 2004 - 03:34 PM


I think the install gap is like .028-.042inch. I don't remember exactly and I don't know how that converts to mm's. Your clutch should engage almost immediately above idle, especially with the light spring. The perch adjuster won't help with this problem. Maybe you should recheck the instructions and check the gap again. If it's still good , call Rekluse. They can help you troubleshoot.
Once you get your clutch working right, it shouldn't stall with the brake anymore. If it does, then your low speed jetting and/or idle speed needs some fiddling. I have to screw up pretty bad to get mine to stall. Good luck. Once you get it dialed you'll love it. :thumbsup:

  • tool

Posted May 25, 2004 - 03:53 PM


in my installation manual it says .76mm - 1.07mm. mine was at .96mm and i'll adjust it to .76mm when i put it all back together.
im just wondering if a tighter gap = more clamping pressure at lower rpms?
the thing is it begins to engage right above idle, but it takes a long time for it to fully engage. it floats a little too much. when i slam the rear brake, the rpm drops almost below idle or even dies.
the clutch doesnt drag. :thumbsup: but, i do have the idle set really low to avoid the dragging. perhaps it is just jetting... i'll fiddle. :awww:

  • Fastest1

Posted May 25, 2004 - 06:22 PM


Tighter gap would equal earlier engagement. :thumbsup:

  • renegade

Posted May 26, 2004 - 07:44 AM


in my installation manual it says .76mm - 1.07mm. mine was at .96mm and i'll adjust it to .76mm when i put it all back together.
im just wondering if a tighter gap = more clamping pressure at lower rpms?
the thing is it begins to engage right above idle, but it takes a long time for it to fully engage. it floats a little too much. when i slam the rear brake, the rpm drops almost below idle or even dies.
the clutch doesnt drag. :awww: but, i do have the idle set really low to avoid the dragging. perhaps it is just jetting... i'll fiddle. :thumbsup:

Tool, your installed gap is right in the middle of the range. If you make the gap tighter, you WILL have serious clutch dragging going on. Tighter gap does not equal greater clamping force at lower rpm. Allthough the installed gap has an influence on the engagement, I believe that is not your problem. If anything, increasing the gap so you can run a higher engine idle without getting clutch drag, and lowering your stall speed may help you out here.

  • rbm33

Posted May 26, 2004 - 03:09 PM


sounds like you need the perch adjuster. i have a works connectin hot start and adjust on the fly clutch and the perch adjuster bolted right up, took a few minutes to figure it out then a quick install and i was off.

i dont use the clutch lever except for motocross starts. i have never killed my bike in a turn and have crased it 2 times!! it hasnt died on me yet which is a big improvement!!

i dont think you can go wrong with the adjuster, i know its another expense but it really makes the z start a complete package. you wont regret it

  • tool

Posted May 26, 2004 - 03:52 PM


i think renegade is right about the higher idle/lower stall speed. thats probably whats killing the engine. but i would like to have the lever anyway. i love the clutch though, very smooth action for an '00. :thumbsup:
im totally spoiled. :awww:

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • RichBaker

Posted May 26, 2004 - 06:29 PM


If you aren't using 2 feeler guages 180 apart you'll never get the gap right....

  • renegade

Posted May 27, 2004 - 04:25 AM


Tool, I think you should try my recommendations. Do what you need to to get a larger installed gap. It's quite safe to operate at the high end of the range. Raise your idle speed, and lower your stall/engagement speed.
The perch adjuster does the same function as the spring sitting down there on your engine case, it is not some miracle fix for your woes. I do know what I'm talking about, I was the tester for the DRZ model z-start. I have had my clutch case open dozens of times to test different variables of set-up. I've also done installations on hondas and ktm's, and have troubleshooted many yz4xxf z-start problems.

  • tyzfryan

Posted May 27, 2004 - 07:36 AM


It took a fair amount dicking around on the install and adjusting-But was is worth it DAMN STRAIGHT it was. It took an o.k. woods bike and turned it into an awesome fun bike to ride even in the tightest stuff. A big plus is you got a couple extra fingers to hang onto the Brute!!!!!!! :thumbsup:

  • tool

Posted May 31, 2004 - 04:03 PM


ok, renegade... ive finally got my bike together and have had some time to mess with the clutch.
i put it together with an installed gap of about .96mm. it was slipping big time and i still couldnt raise the idle without it dragging. so i swapped another stock drive plate for a rekluse one. the gap was .76mm and the dragging didnt get any worse. this setup fully engages at around 6k rpms, which is great for mx because you only use 6k and up there.
however when i ride in tight woods, even for a short time, the clutch is always slipping and heats up bad. even with short gearing. :thumbsup:
im looking to gear it really tall and still be able to do the tight stuff occasionally. i need it to fully engage very quickly, so i can actually use the low end. shouldnt it fully engage by 1/8 throttle? mine slips until 1/2 throttle. im thinking i need to try those heavier ball bearings.
thanx for the help :awww:

  • OC768

Posted May 31, 2004 - 04:47 PM


is this with a new clutch pack per chance? could have some odd (read:warped) components in there? That would add a fair amount of slippage until there is a bit of clamping force..even some oddities thereafter :thumbsup:

  • renegade

Posted June 01, 2004 - 04:13 AM


Yea, something isn't quite right, and it could be your original drive plates. My suggestion now is to call rekluse [don't e-mail them, they're a bit slow to respond that way] and tell them what you're experiencing, and what you've tried. They should be able to help you quickly.

  • tool

Posted June 01, 2004 - 02:35 PM


well, i replaced the friction plates shortly after first installing the z start. just because. im still using the stock drive plates and im not replacing those. $ after $... im done.
i dont think anything is warped. it just feels like it doesnt have enough enertia to fully engage without lots of rpm. im convinced i need a tighter gap, like .56mm at the most, thats what ill try. but i will call rekluse and see what they think.

  • renegade

Posted June 02, 2004 - 04:01 AM


A call to rekluse is in order. A tight gap is going to give you more drag and creep. Before the gen 3 model came out, rekluse used a certain amount of tungsten carbide balls mixed in with the steel ones. The tungsten carbide balls are nearly double the mass of the steel. Different model bikes used different ratios of tungsten carbide to steel for the right set up. For most bike models, the gen 3 version did away with the need for tungsten carbide. Perhaps you could benefit from some.

  • tool

Posted June 02, 2004 - 10:14 AM


ok, i talked to sean at rekluse. he said he has never heard of this problem before on a 426, ever... he had me do a test to make sure the throwout wasnt getting hung up, it wasnt.
so i ordered 5 tungsten carbide balls (at $5 each) :awww:. and he said he cant see me needing any more than 5... which is fine cuz im not spending $60 on friggin ball bearings. it sounded like i was the first one to order these balls for a 426 :thumbsup:.
does everyone else using these clutches just ignore the flesh burning temp of the clutch cover? im suprised my boot hasnt melted to it :lol:.

  • renegade

Posted June 03, 2004 - 03:48 AM


yea, I'm a little mistified myself at what's going on in your clutch case.
Where in colorado do you live?

Related Content


Wilson the Blue Privateer by jetfuel

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  50 replies

Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On January 15, 2017

Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

Is it worth it? (Cam and High compression piston) by macgi77

Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 replies

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.