Clutch plate replacement question

[gbw]

So I'm digging into my clutch that started slipping so bad the bike would not move forward at all.

What I've found:
1. All the springs are below the service limit. I will replace. Check

2. Many of the driven plates (the fiber ones) are within the service limits, but some of them are not. And one specifically looks like it has been ground down to nothing.

In fact there is quite a lot of black grit in the clutch basket. I assume this is from the plates wearing out.

I will replace these plates. Check.

3. Some of the metal plates are in spec (1.6mm). About half the plates are a little less than the spec at 1.57-1.58. A few of the plates are below the spec at 1.54-1.55.

I have not checked them for flatness yet. I'll do that after dinner tonight. I need to run to Home Depot and buy a window pane or something flat to lay them on to take the measurement.

So, finally my question: Should I replace any of these metal plates? If I need to replace some should I go ahead and just replace them all?

Thanks for all the help!

[koolaid_kid]

Sounds like you found the source.
New springs, yes. New fibers, yes. AFA the metals, I would buy some used ones that have been verified to be within tolerance (there are folk here who cherish the first gen GS750s, like TCK) and use those.
A sheet of glass (window pane) is excellent to check flatness, as you surmised.

[rustybronco]

You don't need to drive someplace to shag a piece of glass, take a window out of your house, check the flatness of the steels, clean the window and put it back when you're done.

[gbw]

You don't need to drive someplace to shag a piece of glass, take a window out of your house, check the flatness of the steels, clean the window and put it back when you're done.

My wife asked, "why are taking that picture off the wall?" I explained I was going to borrow the glass from the frame to work on the bike. Well...the picture is back on the wall and I'm headed to Home Depot

[gearhead13]

The clutch was slipping badly enough to wear down the steels
If I was you I would replace the steels too, they are 1/2 the price of the fibers. Then you know you are in spec in both fibers and steels. I would imagine that they are discoloured from the heat and friction.

[Redman]

So I'm digging into my clutch that started slipping so bad the bike would not move forward at all.

........!

1. Springs are "below"? service limit. Below?
I recall measuring length, and if too long (too relaxed) then they were beyound the service limit.
Some folks think they want heavier comptetion springs, because that will be even better, but regret it later. Just newer stronger ones will be lots stiffer than your old worn ones.

2. Aside from the service limit thickness of the fibre plates the hardness is probably more the problem. They get hard from usage, and age, and heat. They could be within the thickness specification but slipp because they are old and hard.

3.(have not had any experince with this) but I would image if any of the steel plates are warn they may not be worn evenly, and will then wear hard on you new fibre plates.

My expereince (twice now) is that after suspecting some clutch slippage on occassion and then notice slippage on accleration or high speed, then replace the clutch fibre plates and springs. Whooo. Man, such a difference.
Probably had been slipping more than I knew. It was almost like I had to learn how to operate the clutch all over again. And you say your is definalty slipping real bad. So, be ready for quite a change in how you have to operate it.
You will think you have a new bike for $150

.

[nutsandbolts]

The clutch was slipping badly enough to wear down the steels
If I was you I would replace the steels too, they are 1/2 the price of the fibers. Then you know you are in spec in both fibers and steels. I would imagine that they are discoloured from the heat and friction.

Second the new plates. You don't want to have to take it apart again in a year and a half when the others decide to go. Its peace of mind in my opinion. (FYI- had my clutch apart 3 time in last 2 months by not doing it completely first time)
Good luck.

[gbw]

1. Springs are "below"? service limit. Below?
I recall measuring length, and if too long (too relaxed) then they were beyound the service limit.

Hmmm. I may be confused. But according to the manual from BassCliff's site, Clutch spring free length spec is:
Standard (when new): 40.4 mm
Limit: 39.0

So it would seem to me that with wear the spring become shorter, not longer. Am I wrong about that?

Based on the advice here and other discussions I've had, I think I'll just order up all new plates tomorrow. Looks like the whole thing should set me back about $180 plus or minus.

While I'm waiting I for them to arrive I can install my new stator and maybe get the Racetech springs and cartridge emulators I ordered installed.

[platinum2]

Hmmm. I may be confused. But according to the manual from BassCliff's site, Clutch spring free length spec is:
Standard (when new): 40.4 mm
Limit: 39.0

So it would seem to me that with wear the spring become shorter, not longer. Am I wrong about that?

Based on the advice here and other discussions I've had, I think I'll just order up all new plates tomorrow. Looks like the whole thing should set me back about $180 plus or minus.

While I'm waiting I for them to arrive I can install my new stator and maybe get the Racetech springs and cartridge emulators I ordered installed.

shorter is wore, "sacked out" from use, new springs should be like 10bucks, you can get a new set of vesrah fibers "real good and inexpensive"! maybe factory steels,or ebay or someone on here might have some, ebay would be the best choice for fibers,and springs, 75.00 max! not near 180 good God, "unless your racing"

[Redman]

...
So it would seem to me that with wear the spring become shorter, not longer. Am I wrong about that?
....

Doah...
You are correct.
Perhaps I was thinking of other application were the spring is under tension (not compression).

You will think you have a new bike for $200.
and..ah, er, and with a new charging system you will have another new bike.

.

[salty_monk]

Looks like the plates were stuck together at some stage & the clutch was activating on only one plate (explains the single plate that was almost ground completely flat...)

You probably need a new piano wire clip to hold the first plate if it's the same as the clutch on the 1000...

[Redman]

Greg,

I have not had the expereince directly myself, but have heard that if clutch plates are wearing strangly (as you seem to have said) that you should check to see that the slots in the baskets are not knotched. I do not know how much knotching is a problem.

Dave.

[gbw]

Looks like the plates were stuck together at some stage & the clutch was activating on only one plate (explains the single plate that was almost ground completely flat...)

You probably need a new piano wire clip to hold the first plate if it's the same as the clutch on the 1000...

Thanks Dan. That makes sense about the plates being stuck together. I can't wait to get the new clutch in and take a ride (after I get the front end back on).

No piano wire clip on the 750. At least that is something I don't have to replace

[gbw]

Greg,

I have not had the expereince directly myself, but have heard that if clutch plates are wearing strangly (as you seem to have said) that you should check to see that the slots in the baskets are not knotched. I do not know how much knotching is a problem.

Dave.

Thanks Dave. Yeah, I took a good look at the basket. No notching. I was really worried about that but all is well from that standpoint.