clutch changes

[Tuned forks]

Has anyone tried replacing the used Yamaha clutch spring with just one new Yamaha clutch spring AND adding the seventh Yamaha wide clutch disc?  Did it solve the clutch slippage issue?  Because I live in a dense urban area, with the requisite heavy traffic, using one used spring and one new spring is not appealing to my left hand.  My FJ has about 34k miles and only slips above 5k rpm and kookaloo throttle.  I've read Pat's excellent clutch slipping file and am going to try a hybrid of his recommendations.  The seventh disc is taking an oil bath right now.

Joe

[Pat Conlon]

Thanks for the compliment Joe. Sure go ahead and try it, it's easy to change if it does not work out.
In any event, clutch pull aside, removing the wire retaining ring from the clutch pack is always a good idea.

The easiest clutch pull I've experienced on my different FJ's was a combo of the Barnett coil spring pressure plate using the light 75lb gold springs and a FJR clutch master cylinder (m/c)

No slip and the clutch pull was like butter.

I think using the FJR clutch m/c is the key, the difference between the larger 5/8" (16mm) dia. piston in the oem FJ m/c and the smaller 15mm piston in the FJR m/c with the smaller piston taking less effort in the pull.
The adjustable lever on the FJR m/c is also a nice feature.

[T Legg]

I did all the modifications including a double clutch spring.After I figured out my clutch wasn't slipping and my problem is second and third gear jumping out,I removed the second new ebc spring and left the original yamaha spring in.I accelerate hard often especially in fourth and fifth and I've never had the clutch slip.

[Tuned forks]

Pat, it was very well written and illustrated.  I knew just what I was doing when digging into the clutch basket because of your pictures.  For those that are interested, here is the link.
http://www.fjowners.com/index.php?topic=1808.msg14307#msg14307

For now Pat, I'm resisting changing the controls out.  There was information in your clutch file about changing to the FJR clutch master and also getting the adjustable lever.  I'd think that would look odd without changing the brake master as well and getting matching levers.

Travis, the most I can liken the slipping clutch on my machine is to hitting the "pipe" on a two stroke.  The revs climb dramatically in the kookaloo zone.

Joe

[aviationfred]

For me, the problem of clutch slippage was accomplished with a combination of mods.

1. Double OEM clutch springs.
2. The 7th wide fiber disc.
3. A Honda RC51 master cylinder. (I know that not everyone likes the look of the round cup design)

I don't know what the bore diameter of the RC51 master cylinder is, but, the lever pull effort with the double spring is no more than the OEM master cylinder with a single spring. I will be putting the RPM Roller detent shift kit in sometime soon.

Fred

[T Legg]

Travis, the most I can liken the slipping clutch on my machine is to hitting the "pipe" on a two stroke.  The revs climb dramatically in the kookaloo zone.

Joe
Quote.                    

 Joe my gear disengagement problem also happens above 5000rpm when you try to go w.o.t. in second or third but it jumps in and out untill you back off a little.if you don't back off it will jump in and out repeatedly.It sounds like the engine is racing.if the clutch is slipping it should be a steady slip until you back off the gas and be worse the higher the gear you are in.

[ribbert]

Joe, the simple fix is a new set of fibre plates, single spring, mineral oil. Full size plate at the back can't hurt and rough up the steels while you're there. There is nothing wrong with a standard FJ clutch but over time the fibre plates become glazed with contaminants from the oil and they get slippery. They don't wear thin like a dry clutch, they just lose friction. A clutch is a really simple component with only a couple of parts that determine how well it works, it's not complicated.


Like all rules, there are exceptions, but a new set of fibres will fix 99% of slipping clutch's.

Increased clamping force is a bandaid, new plates are the fix.

Noel

[Tuned forks]

interesting point Noel.

Joe

[X-Ray]

Joe, the simple fix is a new set of fibre plates, single spring, mineral oil.
Like all rules, there are exceptions, but a new set of fibres will fix 99% of slipping clutch's.

Noel

Thanks for that info Noel. I *still* have not touched the clutch assembly on my '93 (apart from the slave) and at 138000kms, the feel at the lever is getting very weak. I have no slippage to speak of, but I'm thinking a new set of fibres with a new spring plate will get the proper feel back, probably long overdue. I'm guessing that the spring is the weak link as the clutch doesn't disengage until the lever is nearly at the bars, and its a new slave bled propeley, completely different feel to my '94. Its a job I want to do before March next year anyway.

[T Legg]

Check your clutch lever also.One of mine had quite a bit of damage where the lever meets the master cylinder plunger.

[Millietant]

Joe, the simple fix is a new set of fibre plates, single spring, mineral oil.
Like all rules, there are exceptions, but a new set of fibres will fix 99% of slipping clutch's.

Noel

Thanks for that info Noel. I *still* have not touched the clutch assembly on my '93 (apart from the slave) and at 138000kms, the feel at the lever is getting very weak. I have no slippage to speak of, but I'm thinking a new set of fibres with a new spring plate will get the proper feel back, probably long overdue. I'm guessing that the spring is the weak link as the clutch doesn't disengage until the lever is nearly at the bars, and its a new slave bled propeley, completely different feel to my '94. Its a job I want to do before March next year anyway.

Ray, I'm not sure your symptoms describe weak clutch springs - if the clutch doesn't disengage until the lever is nearly at the bars, I'd guess that means the pushrod isn't pushing the plates far enough apart in the lever stroke.

That would make me think your issue is either air in the system, faulty slave seal (but you've already done these two), worn lever (as just mentioned above), or faulty/worn master cylinder/seal.

It sounds like pulling your clutch lever in isn't moving the correct volume of fluid against the slave piston - hence your clutch isn't disengaging.........but, I could be wrong....I'm not a professional.....

[ribbert]

....I'm not a professional.....

Maybe so, but you're on the money.

Ray, I agree with what Dean says, it is not indicative of a weak spring, I recently rode an FJ with 240k on the original spring and you couldn't make it slip if you tried (and I did).
What you describe is (as Dean said) not getting enough throw. The most common cause is hydraulic but it can also be mechanical. The mechanical advantage at the lever means it doesn't take much play on the other side of the pivot point to bring that take up point right back into the grip. (I hate a clutch that does that)
Another cause that is more common than you might imagine is a loose slave, bolts either not tight or stripped. Put you hand on it while you pull the clutch and feel for any movement as you operate the clutch.

As usual, be methodical in your diagnosis, eliminate the obvious and the easy first, for example, does it have enough fluid.  (yeees, it happens)...... FJ clutch's are largely self bleeding, if you can get enough dragging clutch to get it out the door, it will come good with a bit of riding, say 30 mins around the suburbs (or tie the lever back to the grip for a few days  ). Make absolutely sure it's not just bleeding before you delve any deeper.

Clutch's are really simple, there's only a few components and there just ain't that much to go wrong and the common fixes are well documented.

If you are absolutely satisfied the hydraulics are fine, I'd be checking out the lever next, that 15-20mm extra travel at the lever will likely be only a couple of mm at the M/C (the otherr side of the pivot point) The chance of it being something inside the clutch is possible but unlikely.

Let's know what you find.

Noel