Clutch Wear - Mystery and confusion

[David Allaband]

I started a new thread for this, the subject is different now.

I measured my clutch parts and got some confusing numbers. Sorry about not using metrics, I have no metric measuring tools.

Spring free height - .260"
Spring warpage - .004"

Friction plate thickness (three plates) .119", .117", .117"

Steel warpage (three steels) .008", .009", .006"
Steel thickness (three steels) .078", .078", .078"

The only numbers I see that are out of spec are the steel warpage limits. There is some discoloration on the steels but not like big splotches of blue or rainbow or anything like that.

History. I finally tuned the engine (got it done right) and put in a new clutch slave. Rode the bike from NYC to DC (test ride) and the clutch slipped whenever the engine warmed up. Slipped a lot the hotter it got. No slipping on the highway even after hours of riding. Folks on the list told me it was my clutch spring, but as you can see the spring is within the wear limit. So what gives? Is it the warped steels? How did they get so freakin' warped without any other problems? Did they get warped from the slipping? I got this bike at 40,000 miles, did someone put substandard or warped steels in there?

I won't rule out some miscalculation in my measurements but I have used these measuring tools before and I measured everything ten times. I don't want to just jam a new or second spring in there without understanding what's really going on.

Also, that wire people keep telling me to throw out, is it the wire holding in the last steel and friction disc? I didn't take it off or those out because I figured I had enough junk to measure without them.

I have spent more then a hundred hours working on this bike for every hour I have ridden it. I have been working on this bike for a year (just renewed registration) and I have only ridden it less then 15 hours. I'm not even contemplating giving up on the bike anymore, I'm simply enthralled by it's god like power to devour time and attention without giving reward. If there is a black hole in this universe that consumes work, sweat, good will and hope, it's name is FJ and it's sitting in my back yard.

[Pat Conlon]

David, it's the spring.....

It might be within the wear limit but that does not mean that the spring tension is ok.  It's not.

Listen to us.

[SlowOldGuy]

Did you eliminate everything else?

Since it happens hot, I'm thinking the fluid is getting hot and building pressure (lever possibly blocking the master return hole) which is trying to release the clutch.

Next time it gets hot enough to slip, try quickly cracking the slave bleeder valve and see if that relieves any pressure in the line.

DavidR.

[racerrad8]

Also, that wire people keep telling me to throw out, is it the wire holding in the last steel and friction disc? I didn't take it off or those out because I figured I had enough junk to measure without them.

If you did not remove the last steel & friction, then you really do not know if you are going to be good to go. If the center hub is worn at the friction surface then that might be the issue. The friction could be worn out as well as that is the "cushioning" spring and id the first clutch to slip.

I have flat, reconditioned steels in stock, I am waiting on the boat to dock before my next Yamaha order and I have frictions and springs in stock.

Another 1/2 an hour putting it back together and you might well be on your way.

Randy - RPM

[Steve_in_Florida]

If there is a black hole in this universe that consumes work, sweat, good will and hope, it's name is FJ and it's sitting in my back yard.

I assume that you haven't owned a British car (MG, Triumph, Jaguar, etc.). They're *KNOWN* black holes, too!

[terryk]

David, it's the spring.....

It might be within the wear limit but that does not mean that the spring tension is ok.  It's not.

Listen to us.

+1 on the spring. I doubled up on the spring (reused the old on top of the new) after using a single, new spring, and buring up an entire new clutch set in less than 200 miles on a ride.........

[RichBaker]

It's the spring..... Yamaha, and most of the Jap makers, use parts/pieces that feel "good" on the showroom floor, after a few heat cycles, the spring gets soft and starts to allow slippage. Just get an FJR spring and put it on top of the original and you'll be happier than a pig in shit.   

[andyb]

Needs more clamping pressure on the clutch pack.  Either a new spring, two springs, red spring, blue spring...  The stock setup is pretty marginal.  It works when everything's absolutely perfect and you don't ask too much of it, and slips the rest of the time.

And replace those warped steels. 

[David Allaband]

Thanks for all the info everyone!

Can someone tell me if that wire holding in the last steel plate and friction disk is the wire I'm supposed to throw away? I'm having a hard time getting it off and don't want to break it if I need it, but if I don't need it I'll just snap it.

So barring any strange revelations behind the wire it looks like I need a second spring and new steels. Randy has used (reconditioned) ones and I think I'll go with those. I've read that I should replace them all as a set, right? What do you think about my friction plates? The numbers again were .119", .117", .117". Is that good or should I replace them while I'm in there? Should I replace the friction plates "as a set" because I am replacing the steels? Or does "as a set" only mean like parts?

One more thing, there is some wear where the frictions and steels contact the housings. Is this a problem? The book says to inspect for it but does not say what the wear limit is or what I'm really looking for.

I'll wait for Randy to get the clutch spring in. He's patiently helped me so many times in the past he deserves any business I can give him.

I owned a triumph motorcycle, triumph car, and two MG Midgets. I never got any of them to work. I owned a 40 year old Chevy delivery truck, drove it back and fourth from coast to coast and never had to put much more then a wheel bearing into it. Similar story with an AMC Rambler and an International Harvester school bus. My experience with Japanese machines is limited. Lots of experience with BMW bikes, they run like sewing machines (for better or worse).

[bugboy]

Lots of experience with BMW bikes, they run like sewing machines (for better or worse).


I had a BMW R100GS. About as fast and with as much appeal as a sewing machine.  Damn reliable, just no "soul" to it.

[racerrad8]

David,

If you haven't, you need read this, it will answer all of your questions and give you many examples; http://www.fjowners.com/index.php?topic=1808.0

The a stock frictions are new at .119/.120" so I think you are going to be fine. Unless they are black, they should be a dark brown with lighter signs of cork in them.

No, the wear at the drive tabs is not a problem. If they are excessively grooved you can use a file to remove them, but I have never had to do that.

Randy - RPM

P.S., I hope you are not waiting on me, I have plenty of everything is stock...

[Signaller]

Good evening folks,
       What about the oil you are using? I have seen many times in the archives that you have to be careful about not using "energy conserving" motor oils. Specifically ones used in cars because they can contaminate the clutch fibers and cause things to slip. Once again what oil are you using?


Signaller

[Pat Conlon]

Short answer: Anything.... other than car oil that makes your clutch slip.......

[David Allaband]

Thanks for all the help on this one guys. Randy at RPM is an angel or a saint or something like that. I got all the parts fast and it's all back together! Riding up a storm now!

Oddly enough, this is the first new clutch I ever had in my entire life! Feels good!

I put in the double spring, used the old spring and a new one. All new steels, new frictions, did the inner plate mod to add one more friction, did the FJR Master mod, and already put a rebuilt slave cylinder in there. Everything about the clutch is new now except for the hose!

[racerman_27410]

Thanks for all the help on this one guys. Randy at RPM is an angel or a saint or something like that. I got all the parts fast and it's all back together! Riding up a storm now!

Oddly enough, this is the first new clutch I ever had in my entire life! Feels good!

I put in the double spring, used the old spring and a new one. All new steels, new frictions, did the inner plate mod to add one more friction, did the FJR Master mod, and already put a rebuilt slave cylinder in there. Everything about the clutch is new now except for the hose!

nicely done .... enjoy getting all her power to the ground now


KOokaloo!