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KLR650 clutches seem rather robust, from experience of others. Assuming the clutch hasn't been abused (as in, slipped excessively), I'd expect service life beyond 25,000 miles.

Regarding adjustment, the clutch cable is adjustable at BOTH ends, at handlebar lever and also at actuator lever. Have you exhausted adjustment at both these points?

Service manuals have service limits: 2.60 mm/0.102 in. friction plate thickness; 36.4 mm/1.43 in. spring length ('96-'07); steel plate warp 0.3 mm/0.012 in.

Don't know of any tricks for clutch life-extension; with components complying with these service limits, should be adjustable to serviceable condition, IMHO. Not terribly hard to check out (can be disassembled without removing crankshaft nut); not terribly expensive to replace parts.
 

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Very robust.

A partial list of bikes that use the same friction plates, all of which are far more potent than the KLR650:

KLX650
KZ550
KZ750
KZ1000
ZX600
ZX750
ZR1200

Properly used, the KLR650 clutch usually lasts for the life of the bike.

Damocles has pointed you in the right direction; check the lower adjustment.

Tom
 

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Seems to me you're looking at a stretched cable. Rather than a worn clutch.
If the clutch isn't slipping I'd say it's OK.
 

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I use the KZ1000 clutch springs in my stock clutch and haven't had a single issue with it yet after 80,000kms....I replaced it the minute I did my first 685 and engine build to follow KLRCary's recomendation. I never slip the clutch either .......more than normal that is.
 

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KLR650 clutches seem rather robust, from experience of others. Assuming the clutch hasn't been abused (as in, slipped excessively), I'd expect service life beyond 25,000 miles.

Regarding adjustment, the clutch cable is adjustable at BOTH ends, at handlebar lever and also at actuator lever. Have you exhausted adjustment at both these points?

Service manuals have service limits: 2.60 mm/0.102 in. friction plate thickness; 36.4 mm/1.43 in. spring length ('96-'07); steel plate warp 0.3 mm/0.012 in.

Don't know of any tricks for clutch life-extension; with components complying with these service limits, should be adjustable to serviceable condition, IMHO. Not terribly hard to check out (can be disassembled without removing crankshaft nut); not terribly expensive to replace parts.
I've checked the service manual myself, and it shows 2.60mm as the service limit for the Clutch Friction plates. Reading this, and seeing that my friction plates were in the 2.22-2.25 range, I ordered brand new friction plates - EBC brand. I get them, and measure them and the brand new plates are 2.25mm thick. Is the Clymer service manual wrong? Any other sources for the minimum thickness on the friction plates. I'm just not believing the 2.60MM.
 

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According to the Kawasaki service manual, the service limit is 2.75mm. New would be 3ish mm.

2.25mm! HFS!
 

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What year and model are you working on rgmr250? What # of EBC plate kit did you receive?

OEM Base manual for KL650 A's 1987-2007 is the KL600 A manual.

It reads,
Standard---- 2.75-3.05mm ---- Service Limit--- 2.65mm

My 2014 Edition of Gen 2 manual for 2008 & up models reads,
Standard--- 2.90-3.10mm (0.114-0.122inch) --- Service Limit--- 2.7mm ((0.106inch)

Other than 2 or 3 replacement clutch cables, I've got over 80,000 trouble free miles on all my 1987 -A1 clutch parts.
 

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As to the aftermarket clutch plate thickness . . . we do not know what clutch springs were assumed . . . possibly clutch springs of higher rate . . .

Then . . . if the clutch slips, you can always shim the clutch spring bolts with washers! :)

CAVEAT: An expedient advisable only if proper springs and/or clutch plates are unavailable.
 

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The snippet I provided is from the Kawasaki supplement through 2002, Part. No. 99924-1080-58.

Paul correctly points out that the spec is different in the base manual ( Part. No. 99924-1050-01). See attached.

That is interesting, because I believe that the clutch plates were unchanged in the KLR (600 and 650) from '84 to '011.



The latest manual I have, through 2015 (Part No. 99924-1384-09) says 2.9mm - 3.1mm, service limit 2.7mm.

I'm tempted to drag a clutch out of the shed and see what the thickness of the steel plate for the fibers is. I know that every fiber I've got (~30 pcs) is right at about .118"/.122" (3.0-3.1mm).
 

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I'll give some more background on the story.

I have a 2005 with 13,000KM (about 8,000 miles). I bought it earlier this year with about 12,000KM on it. My son has a 2004 with about 22,000KM on it. My clutch pull is 'odd' - I thought it was just a standard KLR clutch pull, until I tried my son's. His is a lighter pull, but smooth and linear. Mine is a little harder pull, but not linear, the pull resistance increases until about the midway point, then seems to lessen. Also, releasing my clutch tends to be a little grabby - makes off-road riding harder (I'm used to riding my Husqvarna on hard-enduro style terrain - it has a hydraulic clutch and has very precise control) when the clutch release isn't smooth. My son's is totally smooth in comparison. So, is it the friction plates contaminated, worn clutch basket, some other internals not working as they should, or something else. All seems odd given the low mileage of the bike.

I put a new (motion pro) clutch cable in - well lubed and it made no difference. I tried the clutch release rod (end of clutch cable attaches to it, it goes into the clutch cover) from his bike on mine, no difference. So, I'm thinking maybe the previous owner used 'friction modifier' automotive oil, which has contaminated the friction plates' material.

So, I purchased a used complete clutch off ebay ($35, so not much $ wasted if it didn't help) - it came with the basket (thinking maybe my basket was notched or something), and all the parts, including the metal and friction plates, washers, nuts etc. I have NOT installed this clutch assembly in my bike yet. So, I decided to measure the friction plates and they were, as mentioned about 2.24mm thickness. So, I figured the clutch assembly I got had worn out friction plates. So, I ordered brand new EBC friction plates (I'll get the part # off the box when I'm home), and figured I'd measure them, and they are 2.25mm thick. So, I'm thinking that the Clymer manual must have a typo in it (I've seen it before), but it sounds like, if anything, the Clymer is listing the service limit as lower than the factory manual does.

Here's a thought - how much will the plates 'swell' after soaking in oil (if at all)? The ones I got off ebay, in the clutch assembly, weren't entirely dry, they still had some oil on them, but the EBC ones I measured completely dry.

I'm planning on doing the doohickey (once the parts arrive), putting in a low-profile oil drain plug, and swapping clutch assemblies (with the new friction plates) all at once. I'll measure my friction plates when I take them out and see what thickness they are.
 

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I'll double-check tonight, but it looks like I got the standard CK series clutch plates (CK4435). I haven't measure the spring length yet - I'll measure the ones I got from eBay, then measure the ones that come out of my bike.
 

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Measurements aside, how does the clutch PERFORM?

Does the clutch release fully when the clutch lever is pulled?

Does the clutch SLIP when the clutch lever is released fully?

Does the clutch transfer power smoothly from the engine to the drivetrain when starting off?

Unnecessary to fix something that ain't broke, IMHO. Operational deficiencies can be addressed. Wouldn't worry greatly over clutch disk thicknesses, unless related to some operational deficiency.

(Will leave discussion of the dread, "friction modifier" pox, to others with direct personal experience/observation of the heartbreaking phenomenon . . . :) )
 

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That kit comes back to all the right bikes.

Something is really wrong, though. Or at least odd.

I just measured the ears on a handful of friction plates. This is a measurement of the thickness of the steel plate to which the friction material is bonded.

The ears range in thickness, which may be a sheared-edge thing, but the thinnest one was 2.7mm. This was on two Gen 1 clutches and two Gen 2 clutches. This was a quick measurement with a caliper. If any more detailed, and precise, information is needed just let me know.

If the EBC are truly 2.25mm as measured on the friction material, the steel plate has to be 2mm or less in thickness.

I don't mean to disparage any aftermarket company but, with regard to clutches and brake pads, I have found nothing that is really better than OEM.

Clutch springs are another matter. I'm using Barnett.
 

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Measurements aside, how does the clutch PERFORM?

Does the clutch release fully when the clutch lever is pulled?

Does the clutch SLIP when the clutch lever is released fully?

Does the clutch transfer power smoothly from the engine to the drivetrain when starting off?

Unnecessary to fix something that ain't broke, IMHO. Operational deficiencies can be addressed. Wouldn't worry greatly over clutch disk thicknesses, unless related to some operational deficiency.

(Will leave discussion of the dread, "friction modifier" pox, to others with direct personal experience/observation of the heartbreaking phenomenon . . . :) )
Clutch releases fully when lever is pulled (no 'drag').

Clutch does not Slip (5th gear, full throttle, no slip)

Clutch does not transfer power smoothly from the engine to the drivetrain when starting off - at least not consistently - it tends to 'grab' when releasing the clutch. A lot like a new rider often gets - they let the clutch out 80% of the way smoothly, then let it go the last 20% and it 'jerks'. I have found that slipping the clutch for a longer than typical period when starting off solves the problem. If it weren't for having my son's 2004 to ride back to back with mine, I'd say it's user error and I'm dropping the clutch too quickly, like a new rider, but I'll hop on his bike and ride the same and not have the same issues. Also, the 'feel' of the clutch pull isn't quite 'right'. Engine off, pulling the clutch of each of the bikes, his is noticeably smoother and linear in the pull. Mine 'feels' like the plates are hanging on the clutch basket slightly, which would be very unusual for a bike with such low mileage. And, yes, the best solution at this point is to open it up and take a look at the basket etc., which I'll be doing this week, just waiting for the doohickey parts to arrive (they tried to deliver today while I was at work), which should be soon.
 

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That kit comes back to all the right bikes.

Something is really wrong, though. Or at least odd.

I just measured the ears on a handful of friction plates. This is a measurement of the thickness of the steel plate to which the friction material is bonded.

The ears range in thickness, which may be a sheared-edge thing, but the thinnest one was 2.7mm. This was on two Gen 1 clutches and two Gen 2 clutches. This was a quick measurement with a caliper. If any more detailed, and precise, information is needed just let me know.

If the EBC are truly 2.25mm as measured on the friction material, the steel plate has to be 2mm or less in thickness.

I don't mean to disparage any aftermarket company but, with regard to clutches and brake pads, I have found nothing that is really better than OEM.

Clutch springs are another matter. I'm using Barnett.
I'm measuring the friction plate thickness at the thickest part - which is measuring the friction material on both sides, plus the metal plate the friction material is mounted to. Measuring at the friction 'tabs', not the valleys between them. Using a digital micrometer and resetting to 0 before starting - moving the micrometer out and back in to ensure when they bottom that the reading is still at 0. I haven't yet measured the steel place that the friction material is mounted to yet.
 

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Uneven clutch engagement?

Checked flatness of metal clutch plates?

I think flatness specs are in service manuals; a pane of plate glass is useful in measuring flatness.
 

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I decided to test my micrometer - I measured a .88mm feeler gauge, and the micrometer read .98mm. Reset it to zero, re-checked, read .95mm, slid it back and forth, zero'd again, and now it reads .88mm. I re-measured the EBC friction plates and now I get 3.05mm thickness. Time for a new (more consistent) micrometer. I'd reset and tested several times when I read the thickness, but it somehow seems to keep getting odd readings. Every time I checked yesterday (I checked about 10 times, between the new EBC plates and the old plates) it read consistently in the 2.25mm range, and was zero when closed. I measured the springs and they were all in the 37.35-37.4mm range - which appears to be within the service range. When I take my existing clutch out, I'll measure them. In the meantime, I'll look for a new digital micrometer...

I'll check the metal plates that are in the bike once I get it all apart and out.
 

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Got it all back together, did the Doohickey while I was at it (spring was broken, but doohickey was intact - did my son's 2004 the next day, and same thing - broken spring). Clutch was a little better, but still had a harder pull than my son's 2004. So, I added one of those easy-pull clutch gadgets (I'd had a similar one on the KLX250S I had) and it makes my clutch pull lighter than his. Took it for a test ride and all was good. Clutch pull is lighter, and the friction zone is a little larger, so easier to modulate the clutch.
 
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