Clutch upgrade

[Sarge]

Good day, all.

I’ve had my Z900 since 2017 and it has 15,000 miles on the clock.  I have experienced clutch slippage here and there with hard riding in north Georgia, the Dragon, Cherohala, Moonshiner, etc. under hard acceleration, mostly in 3-5, and high speed in 6th.  It has recently become more frequent.  I corrected the lack of clutch cable free play the day I purchased the bike.  I’ve always felt like the actuator arm return spring is not strong enough, but I’ve manually pushed the clutch lever out to the stop while riding hard and it had no affect when slipping was occurring.  I might fabricate a small piece of aluminum to JB weld to the actuator arm to preload the spring about 3mm to correct that.  I’ve recently been considering selling the bike, but honestly, the Zed has been one of my favorite bikes in 32 years, even next to my RZ350.  So, I’ve decided to keep her and installing an SC Project full Ti system, PAIR block off, filter, ECU flash by 2WheelDynoWorks (they told me they have a flash specifically for this setup), and I have the Brock’s HD clutch springs.  I’m sure that will breed more excitement out of her.

I’m going to inspect the clutch and evaluate the condition of the friction/drive plates and refurbish the clutch (if required) and installl the springs for now and perform the rest of the upgrades and check sync of the throttle bodies once winter sets in, as I’m currently restoring an 85 Yamaha Maxim 700 and want to get it completed.

That having been said, I want some feedback on which friction and/or drive plates I should use if they are worn out of spec (drive plates blued, etc,)?  If I’m using the Brock’s springs, are 2017 OEM clutch components sufficient?

Thanks in advance.

Sarge
Craig

[RobZ900]

Recently fitted the heavier springs from Barnett to my 2017 in anticipation of having the ECU flashed (done now). The feel at the lever is marginally heavier, but only to the extent that you can feel there’s a difference but without making the clutch pull any harder work. I only wish I’d done the clutch springs sooner as it feels like the gears are engaging better since the spring change. As for the actuator, recently saw a kit for a different bike where they fitted a spring between the actuator and the casting where the adjustment nuts go to help with the return. Perhaps something to consider if you feel the need, but honestly I’d just try the clutch springs first and see what you think.

[Sarge]

Originally Posted by RobZ900

Recently fitted the heavier springs from Barnett to my 2017 in anticipation of having the ECU flashed (done now). The feel at the lever is marginally heavier, but only to the extent that you can feel there’s a difference but without making the clutch pull any harder work. I only wish I’d done the clutch springs sooner as it feels like the gears are engaging better since the spring change. As for the actuator, recently saw a kit for a different bike where they fitted a spring between the actuator and the casting where the adjustment nuts go to help with the return. Perhaps something to consider if you feel the need, but honestly I’d just try the clutch springs first and see what you think.

Thanks, Rob.

Indeed, the return spring is likely just a very minor annoyance and not the real problem with the earlier models as you (and I) both seem to allude to.

Hope everything is going well for you across the pond…cheers!  Thanks for the feedback.

Craig

[RobZ900]

All good thanks. Definitely give the clutch springs a go. I knew I was going to have the ECU flashed and had read that a few people started having problems with clutch slip after tuning the bike, so thought I’d avoid the problem altogether and fit the clutch springs first. Didn’t really know what to expect, but it’s great and no clutch slip since.

[Cazzy_R]

Originally Posted by Sarge

...... I want some feedback on which friction and/or drive plates I should use if they are worn out of spec (drive plates blued, etc,)?  If I’m using the Brock’s springs, are 2017 OEM clutch components sufficient?

Thanks in advance.

Sarge
Craig

 One of the friction plate part numbers used on the 2017MY is now NLA. Suspiciously it was only ever used on the 2017 Z900 and nothing else prior or since.
 So if you order a fresh set of OEM frictions they will all be the same part number and the clutch will be better for it.

[Sarge]

Thanks for the info, Cazzy_R; I’ll look into that.

[Sarge]

Well, I pulled the clutch pack and everything looks good.  The friction plates are all in the middle of the standard thickness range, and the drive plates (once wiped clean) look good with no bluing.  The stacked clutch pack is within the thickness range specified in the manual as well. There is a little wear on the pressure plate ramps, but seems normal for the mileage, with no ridges/burrs, and no bits/shavings present.  The drive plates, pressure plate face, and clutch basket are cleaned, and I have the clutch pack soaking in oil and ready for reassembly, so in will go the Brock’s springs!

Sarge

[Sarge]

Took my Zed out for a test ride with the Brock’s springs…seems like a different bike…and no more slippage.  The clutch lever pull is still nice and light also.

Sarge

[RobZ900]

Originally Posted by Sarge

Took my Zed out for a test ride with the Brock’s springs…seems like a different bike…and no more slippage.  The clutch lever pull is still nice and light also.

Sarge

See what I mean, you can tell it’s different but without being heavy. Hard to describe, but better isn’t it. As it should have been to begin with I think

[zed9]

I had good results with Brock’s springs. I’d heard the stories of slipping so when my clutch slipped just once under heavy acceleration I ordered Brock’s springs and installed them. No slipping any more.
I’d describe the pull as still very light only you can actually feel the lever resistance with a gloved hand.