Re: Clutch question

[FJ_Hooligan]

You didn't get something aligned correctly during reassembly.  Others have reported the same symptom after putting the clutch back together.  A second disassembly/reassembly usually corrects the problem.

I think if you don't get the pressure plate aligned properly you can still tighten it down but it won't be putting any pressure on the disks, thus you get no drive.

[Temblor]

I was able to shift into gear, but would not move rim on center stand. So I thought I would change fluid bleed clutch, think I took some air in.. will not engage, now to buy mityvac? see if I can bleed? Hopefully slave master cylinder ate good, but that does not solve the problem why tire would not turn while running in gear? Maybe in the short push rod supposed to be sticking out?

[Temblor]

You didn't get something aligned correctly during reassembly.  Others have reported the same symptom after putting the clutch back together.  A second disassembly/reassembly usually corrects the problem.

I think if you don't get the pressure plate aligned properly you can still tighten it down but it won't be putting any pressure on the disks, thus you get no drive.

Still having problems understanding this.
Can someone answer this question: Is it possible my slipping clutch was caused from a faulty slave or master cylinder clutch problem in the first place? I had some slight slipping from last year, then this year I rode it once and at the beginning of ride it only slipped when I accelerated hard in 3rd gear. But by time I got home the bike would barely move, it was slipping so bad. It seems odd that it went to that degree that fast? Maybe I have some other problem?  
To start at the beginning, I removed #1 small friction plate (And 2 metal spring/retainer) replaced them with a wide friction disc, removed wire clip and installed new FJR1300 Clutch Spring, After re-assembly, I still do not know why my transmission would not engage back wheel on center stand when I shifted into gear?
SO I decided to try bleeding clutch system and I let some air into clutch lines. Now I cleaned system & have tried to bleed system with a mityvac for over an hour and I can not get my clutch to function.
At this point I guess I am going to order a slave and master rebuild kit and rebuild both. My reasoning is I do not want to rebuild one, bleed system, only to find out both needed to be rebuilt, then I have to wait to order parts again.  
But I still am wondering if something else was wrong in the first place?
Bike has 25k on it.
Thanks for any input

[racerrad8]

PS: RPM is currently out of Master Cylinder kits, anyone have a link for 2 kits I need?

Clutch rebuild kits arrived in today's UPS orders; Clutch Rebuild Kit

There are two choice on the slave rebuild kit. I offer both the O.E. kit and aftermarket.

Yamaha Slave Seal Set
Slave Cylinder Rebuild Kit

Randy - RPM

[FJ_Hooligan]

At 25K, you should have plenty of clutch left even if it was abused.  There are owners with many times that mileage on stock clutches.

Did you measure the friction and steels?  Were they in spec?

If so, then it's possible a master cylinder could be the cause.  If the m/c plunger moves enough to block flow back to the reservior the engine heat could potentially build pressure in the slave.  If enough pressure builds up then it might cause the clutch to slip progressively worse as you rode longer.  But it should return to normal after everything cools off. 

The chances of the above are remote.  I think I've read about a front brake dragging when air pressure against the lever blocked the master reservior, but I've never heard of this happening with the clutch system.  What you describe sounds like a totally worn out clutch or a misaligned pressure plate.  Either one of these would result in no pressure on the clutch pack and no transfer of drive.

Typically if/when a master or slave fail, there will be signs of leakage indicating a need for rebuild.  If you don't see leaking fluid, I'd go back into the clutch cover and retrace the assembly steps.  With the slave removed, the clutch should be locked up and transfer power to the rear wheel when placed in gear.  If it doesn't then it's not a fluid problem; something is not right with the clutch assembly.

[andyb]

At 25K, you should have plenty of clutch left even if it was abused.  There are owners with many times that mileage on stock clutches.

Correction:

I destroyed a clutch in well under 15k.

Pipe/pods/jetting and >100 dragstrip runs?  Launch the bike while laying on the tank, WOT off the line and 5500rpm right from the hit?  The FJ clutch is pretty pathetic from stock IMO, throwing a coil conversion at it makes it rather more usable, but even then it has limitations.  It's not weak like the current literbikes are, it's cut more from the bigbore mold as far as clutches, but it does have limits.

Riding hard when it's still slipping can absolutely demolish the plates in a shockingly short amount of time.  At the track, slammed to the ground and launching at stock wheelbase, you're probably not fully engaged for 1.0-1.3s or so per pass, hotlapping making it worse, but having it slip in fourth gear when standing on it, it's easy to slip for 5s or more each go.  It eats them up.

So I agree with the spirit of your statement, but plainly, you don't know just how much abuse you can really give to the things  Should last pretty well during even aggressive riding, but abusing it can go quite a bit further...

[FJ_Hooligan]

Well, duh Andy.  If you treat it like shit you can ruin anything.

I was making an assumption that the bike didn't spend it's 25K at the strip.  

I also assumed that it wasn't salvaged from the bottom of the ocean.  Usually a safe assumption but you never really know.  But feel free to point out every nit.

On the other side of the spectrum, I'll bet Lee C. is approaching 300K on his ORIGINAL clutch so with your 15K the average clutch life must be 157.5K.  That should be an easy enough target. 

[andyb]

Just wanted to point it out.  Never know what a prior owner may have done with things.

And more importantly, if it's been slipping during normal use for any length of time, that wears it out faster than even abusive use.

[ribbert]

Oh dear, more speculation about what makes a clutch slip, the FJ clutch being weak, what is a reasonable life expectancy for a motorbike clutch, drag racing (Huh?).......

The following comes with the disclaimer that it is a generalization and assumes the bike has been subjected to normal use, which most bikes have. Please, no race bike examples.


Every slipping clutch post here reports the plates are in spec, of course they are (unless you bought AndyB's old bike) The plates are protected from the friction that would otherwise wear them down by the oil (the same oil that protects the metal to metal parts in the engine from making contact)
With proper use of the gearbox, this only occurs when moving the bike off from rest anyway, not much work. It should last forever considering the total surface area of the plates, but it doesn't. 50,000 miles is considered pretty good for a big bike.

As clutch slip is load relative, many of the unusually high mileage ones I have seen are simply on bikes that are not ridden hard. I have reported slipping clutches that the owners are unaware of, not because they don't notice the slip, but because they don't ride the bike hard enough to make it slip.

A dry clutch in a car (or a BMW motorbike) has no such protection (oil) but will do 100's of 1000's of miles, launching much more weight.

Can someone explain to me why a wet clutch doesn't last as long (Yes, Pat, that is a loaded question) and why the FJ clutch is considered a weak point.

As was pointed out, allowing the clutch to slip while riding will destroy it in no time. Depending on you ability to pick when and by how much it is slipping you could achieve this in one ride!

I have never understood how even the mechanically challenged can not tell when a clutch is slipping, it is such an obvious thing. I have seen it described as lacking power, engine makes funny noises when overtaking, tacho goes haywire at full throttle, fuel starvation, bike smells funny etc.

I welcome anyone's views on this and please, as Hooligan says, no race bike or ships anchor examples.

Noel (clutch pedant)

[FJ_Hooligan]

Good point Andy and Noel, riding with a slipping clutch will rapidly wear it out.

Back to the problem at hand.  I will assume after the horrible slipping episode that Temblor has replaced the frictions plates with new ones, the steels were okay, and the master and slave are not showing signs of leaking.  Now the clutch is assembled and it will not transfer power from the crank to the transmission input shaft.

Personal experience: 
Against Noel's advice (sorry, I had to go there :-) I installed a second spring in my clutch.  When I put it back together I had the exact same problem.  Put the trans in gear and the bike goes nowhere.  It's been several years ago so I can't remember whether I had a normal feeling clutch lever pull or not.  All I remember is panicing that the clutch did not work.  I disassembled the clutch looking for errors.  I saw none.  I reassembled the clutch and this time it worked.  I came to the conclusion that I didn't have the pressure plate lined up correctly which prevented the spring(s) from loading up the plates. 

[andyb]

Racing is one of the things that motorcycle owners do, and is arguably normal use, so it does go on the list.  My point was that riding with a slightly slipping clutch is more damaging than doing back-to-back hard launches at the strip.  

I'd call the FJ clutch weak because in stock form it slips when the usual bolt-ons are put into the motor.  At least, mine did, and I appear to be decidedly not alone in this.  It's also shared in gross design with that of the VMax, though not directly interchangable, and they're known to be prone to slip on those bikes for the same reasons.  The diaphram style clutch was also used on the early R1's, though I don't recall hearing about them having troubles with them as much.

I've dragraced every motorcycle that I've owned, for the past 12 years.  The people that I ride with in my area have done the same.  So heading off to the track for a weekend is "normal use" and I'm pretty tired about hearing that it's such an unsual example.  When the FJ1100 was originally introduced, iirc part of the presslaunch was done where?  At the dragstrip.  As was the VMax, thinking about it, when they were taken to the strip with Gleason riding to prove how fast they were?  Perhaps your normal riding doesn't include this, but mine certainly does.  Sport-tourers need to be able earn the sport end of their title sometimes.

I would imagine that touring two-up with a huge pile of luggage is more stressful to the clutch.  Partially because you're going long distances and over long timeframes, partially because if there is any tiny amount of slip, it will be magnified from the load placed against it.  A heavy day at the dragstrip might involve full load against the clutch for nearly a minute, at most.

Gentle use and light loads make life easier on a clutch.  It also begs the question of why exactly you'd need such a massive engine if you weren't willing to use it  

I agree that a grossly slipping clutch is almost impossible to miss for anyone with any sense of mechanical sympathy.  A slightly slipping clutch may not be, as during "normal use" it may just take an extra instant to lock up, feeling slightly spongy and slow to respond.  Once the clutch pack is locked, the difference between static friction and sliding friction is usually enough to keep it locked up unless it's grossly bad.

[Mark Olson]

I have surmised it is a built in protection so second gear dosen't pop out.

[simi_ed]

Didn't work for me!  2nd gear still went NFG!  Then 1st too ... Perhaps 1st was not really clutch related, maybe an excess of torque ...  1 good twist of the wrist yielded this:


Nothing an undercut gearset & new 1st gear fork couldn't fix.

[Temblor]

At 25K, you should have plenty of clutch left even if it was abused.  There are owners with many times that mileage on stock clutches.

Did you measure the friction and steels?  Were they in spec?

Yes friction and steel were all within spec.
"misaligned pressure plate"?
Yes could be.. any tips on how to align properly?

But now it seems that I have gotten air into clutch system because I can not get bike to engage in gear now to test my 2nd clutch assembly!.
I tried bleeding for couple hours with mityvac to no success.  So I am going to rebuild slave & master?

[Burns]

http://www.fjowners.com/index.php?topic=1808.0

Thanks For all the help. My Fiber clutch discs (with 25K) are 2.96 - 3.05 in thickness.
I am ready to remove #4 (Spring seat) #5 (Spring) #6 (Narrow Disc) #8 (Large Wire Ring)
And remove #3 (Clutch Spring)  replace it with Wide clutch disc and FJR1300 Clutch Spring.
So I will end up with 7 Wide with only 1 narrow.   
I am not going to double up clutch spring because I do not want to modify master cylinder at this time.
I might keep the original spring however and add later if necessary.
All good?
Hope this cures my clutch slippage.

Don't have hight expectations of this alone fixing the clutch slip. It is more of a "good thing to do while you're in there" than a fix for a slipping clutch.

Clutch's need two things to work, friction and pressure. The fibre plates providing the friction don't so much wear down as become slippery, for a number of reasons. The spring, providing the pressure, loses some, but not a great deal of it's force over time. I have found that new fibres and a 100,000km old spring worked well but threw the spring in for good measure. In my experience it is usually the fibre plates, not the spring, but it is good practice to replace the spring anyway. Just like in a car, you never relplace just the clutch plate or just the pressure plate and you always install a new throwout bearing. In other words, you don't do half a job, if the clutch is stuffed, replace it.

The common fix recommended on the forum (not by me) is to compensate for the slipping plates by doubling up the spring, a crude but effective fix. As popular as it is I have noticed some members recently removing it, having tired of the heavy clutch.
The FJR spring is an FJ spring, it is no stronger, it's just cheaper to buy as that.

The average life of a wet clutch on a big heavy bike is 60-80,000kms but this can vary dramatically depending on use. Unlike a dry clutch, the life expectancy is also affected by things such as regularity of oil changes, type of oil used, additives and of course, use.

Clutch's are not very robust, because used as intended, they don't need to be. This means a poorly used or abused clutch can have it life shortened dramatically.

The advice here will be a second clutch spring, my advice is to replace the worn parts with new ones, that being the fibre clutch plates and a new spring for good measure, this will return the clutch to as new condition and retain the light feel at the lever. Your choice, both will stop the slipping.

Because of the wildly varying use and abuse of clutch's, the above assumes slippage is wear and tear from normal use.

This guy unintentionally destroyed a clutch in 30 secs from improper use.

http://youtu.be/bM3So0U1BMQ

Noel

Thank you so much for the Corvette Darwin Award url.
What a colossal dumb fuck!