Clutch problem

L.A.B. said:

Robb2013 said:

the culprit?

Click to expand...

What is the actual stack height measurement?

http://atlanticgreen.com/clutchpak.htm

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Robb2013, do you have a dial caliper or a set of micrometers. You can get a dial caliper for $20 at Harbor Freight.

You need to measure the thickness of the whole stack as indicated in the informative link. At a glance your stack seems short by perhaps .100 (1/10) but this needs to be confirmed.

The diaphragm look properly oriented. No worries there.

Glad your up and about.

L.A.B. said:

Robb2013 said:

the culprit?

Click to expand...

What is the actual stack height measurement?

http://atlanticgreen.com/clutchpak.htm

Note there is a discrepancy between dynodave's (Atlantic Green) and the Old Britts clutch stack height figures because the Old Britts measurement does not include the overall height of the pressure plate.

Click to expand...

Do you want me to take all the plates out and measure them with a cailiper?

pvisseriii said:

L.A.B. said:

Robb2013 said:

the culprit?

Click to expand...

What is the actual stack height measurement?

http://atlanticgreen.com/clutchpak.htm

Click to expand...

Robb2013, do you have a dial caliper or a set of micrometers. You can get a dial caliper for $20 at Harbor Freight.

You need to measure the thickness of the whole stack as indicated in the informative link. At a glance your stack seems short by perhaps .100 (1/10) but this needs to be confirmed.

The diaphragm look properly oriented. No worries there.

Glad your up and about.

Click to expand...

OK, I"ll do that and be right back. How does this get short anyway? Bike has 16,000 miles and the friction plates are almost like new. Where does the wear occur other than the plates which obviously have been replaced recently.

OK, I measured the stack, it varies between 1.046 and 1.056 depending on where I measure it.

Also, I noticed all of this crud inside the channels that the gears on the steel plates sit in. Obviously I need to clean this out, but could this have made for a hard pull?

Glad you bounced back so quick, cool. Many a Cdo has to have an extra steel spacer plate to bring the stack about flush to the teeth. This is also reason for various thickness pressure plates. Dial and caliper micrometers should be supplied with Norton tool kits, but don't need it for clutch except to report-impress others online. I mix-match till spring just allows circlip to slip in w/o bind, then measure for similar reasons as best timing setting. i've not been able to wear out any plates to matter, even after a number of sandings required each year, till I went to the dark side with automotive ATF. I use a magnet to suck out the steel plates. Too bad ya didn't observe this earlier in week as I've a nail on wall with a handful of used extra plates to mail. If sticking with your frustrating hobby horse for long term, watch ebay to snag an old set of plates for stock pile wall decor.

All that crud could have something to do with it. Are there any notches in the clutch center where the friction plate ride? Photo please.

This is where I get a little confused. The Atlantic Green site says you are .110" to.130" undersize but Old Britts web site says you are good to go.
Lab?

My plates plus the pressure plate come within about .080 of the circlip grove. It means I have to keep the adjuster stud at about 1/8 turn or less when setting up and my pull is harder than I like, but not bad, it breaks over just before I hit the handle with the hand lever and I can hold it there with my pinkie but it takes at least 3 fingers to pull it there. I asked Fred about this when I had his different thickness plate kit, and he seemed to think that was about normal. But I know some that have added an extra plain plate between the last friction plate and the pressure plate to bring it up closer to the groove which results in an easier pull and you can leave a bit more slop in the adjuster. That's what I plan on doing. I think you could do the same Rob. If you just lay all the plates in the clutch including the pressure plate and diaphragm and see how close it comes to the groove with the compression tool on and the spring pulled there is no pressure in the pressure plate with the spring , there really isn't anything to measure except that gap between the top of the diaphragm and the groove. If it's real close you should be good, if you can put another plain plate in there, go for it.

Your diaphragm spring looks right, but whey you install it, it looks to be suspicious to me. Those fingers should press on the ring around the outside of the pressure plate. I'm wondering if you're following the exact procedure that's spelled out in the rider's handbook, with letting off the cable first, setting up the free play in the clutch lever/ball, adjusting the adjuster and then setting up the cable again?

Glad you're better.

Dave
69S

pvisseriii said:

This is where I get a little confused. The Atlantic Green site says you are .110" to.130" undersize but Old Britts web site says you are good to go.
Lab?

Click to expand...

That depends on whether Robb2013 measured the stack height by the Atlantic Green or Old Britts method (I'm guessing Atlantic Green)?

pvisseriii said:

All that crud could have something to do with it. Are there any notches in the clutch center where the friction plate ride? Photo please.

This is where I get a little confused. The Atlantic Green site says you are .110" to.130" undersize but Old Britts web site says you are good to go.
Lab?

Click to expand...

At this convenient juncture I'll comment and try and distinguish my data from OB. I entirely understand the confusion since OB data IMO is VERY misleading and not though out or described as to any engineering principals to be solved or satisfy.
Confusion is good for business though......
My article was written about 5 years before Fred and Ella even started "articles".
How much more time do I want to spend on writing/editing articles that I don't get a penny for?
anyway:
http://atlanticgreen.com/ndnsclutch.htm
from my page""
Clutch Stack Height
Since the easiest clutch is when the clutch diaphragm spring is about .68” of deflection (175 lbs) and clutch pull is about .1”, the engaged position should be around .58” of diaphragm deflection to get the sweet spot. Therefore, the diaphragm appears to be about .03” inverted beyond flat (.55”) when engaged. The problem is how do you get the diaphragm to be at a certain position when assembled? You adjust the internal clutch stack height, the diaphragm is usually extended a bit to much. Therefore, you add thickness to a component in the clutch stack height. You could have a custom (thicker) backing plate made to be placed in the rear of the clutch basket, or you can add a clutch steel plate .080” thick. You can see using a straight edge on the diaphragm, if it is flat, extended or inverted. It is interesting to note that as the clutch wears, it always gets harder to pull until it finally gets to .40”extended. Then its up to 325lbs of pressure! I don't necessarily endorse this as a must do modification. But you should understand what is happening if you decide to go through with it. The lowered clamping pressure may cause slipping.

All this clutch stack mumbo jumbo ..... 107 posts worth minus barfing....no rocket science here .....even Ol Brits should get it right but ...I keep warning you guys but I also don't want to be a pest..
Hasn't a single one of you thought this out? ,,FULL STACK HEIGHT...FULL STACK HEIGHT...FULL STACK HEIGHT...FULL STACK HEIGHT = http://atlanticgreen.com/clutchpak.htm why?

1. You measure the depth of the empty clutch basket. Which will determine the position of the underside of "A" flat diaphragm.

2. This distance (1above ) gets filled by the FULL STACK HEIGHT (not the Ol brit stack height).... IMO You should shoot for a stack height that causes the diaphragm to be .030" extended (to give you a slightly extended (inward) shape) to a max of flat... The exact basket depth varies especially belt drives. The basket depth to clutch stack relationship= (FLAT diaphragm) is the whole math problem to solve NOT how full the splines of the basket are. :idea:

3. As you pull the clutch it finally gets flat then goes inverted and eventually you might get the relief feel depending on the grind of the release lever cam and if it pushes far enough.

I'll go back and edit my clutch article to make it lawyer correct since no one seems to catch the miniscule errors in language. I'll admit this above relationship was not "in your face" emphasized, But I never though it was all that hard to understand?
The diaphragm spring rate graph and the release cam graph are the real horsepower for the article.

Fantastic. So, Atlantic Green includes the diaphragm and Old Britts does not. I this a fair "assumption"?

And Robb2013, exactly what all did you measure? Be specific. Be very specific.

I assume the spring as clearance in the drum to allow it to be "deformed" Just a check ,because if the drum is to small or the spring is too big , well the spring will resist being "bent back" :?:
Any one Know the Dimensions, Spring dia/drum dia?

Thanks Dyno,

I guess it takes about 10 times reading it and realizing what is going on. So if my early clutch pack has parts that fall in the standard thicknesses, which they do, I have 1.167" of stack height. When I install them, and still have the tool on the diaphragm, I have a space of approx 0.080 from the top of the diaphragm to the circlip groove. Are you saying that if I add a .080 plate to take up that space, it indeed may make the clutch easier to pull, but now are operating with the spring in a 'less pressure' situation and clutch slippage may result?

I can adjust my clutch to operate fine as it stands, but I must leave a very minimum of free play between the adjuster stud and the rod (like 1/8 turn), otherwise I never get that break-over point and the gears are hard to operate because the clutch is not fully dis-engaged. May it be that I need a very thin plate to add a small amount of pack height?

Believe me, I've been thinking about this, but didn't think about the pressure on the clutch plates depending on the depression of the diaphragm springs.

Dave
69S

pvisseriii said:

So, Atlantic Green includes the diaphragm and Old Britts does not. I this a fair "assumption"?

Click to expand...

It's the difference in the way they each measure the pressure plate.

Atlantic Green:

Pressure Plate
Early THICK pressure plate 06-0745 =.347” thick
Late THIN pressure plate 06-3768 =.227” thick

Click to expand...

Old Britts:

Pressure plate is: 0.225”
Pressure plate is: 0.102”

Click to expand...

L.A.B. said:

pvisseriii said:

So, Atlantic Green includes the diaphragm and Old Britts does not. I this a fair "assumption"?

Click to expand...

It's the difference in the way they each measure the pressure plate.

Atlantic Green:

Pressure Plate
Early THICK pressure plate 06-0745 =.347” thick
Late THIN pressure plate 06-3768 =.227” thick

Click to expand...

Old Britts:

Pressure plate is: 0.225”
Pressure plate is: 0.102”

Click to expand...

Click to expand...

I measure the FULL thickness of the pressure plate because I want the FULL STACK HEIGHT which fills the space from the DIAPHRAGM down to the bottom of the clutch basket. if they are the same you will have a FLAT diaphragm spring. If you don't know this number...or how far off you are from FLAT...then you are just playing horse shoes. The diaphragm curve is fairly repeatable in it's characteristics but FLAT has NO reference to the drum depth or position above the variable bottom of the basket. Being flat at rest or a known amount of extended at rest gives you some idea of the results you could expect and how to achieve it. If you are too close to flat or inverted at rest, you should expect the clutch to slip.
If you don't have the stack height numbers you don't know where you are or how to get where you want to be...even my numbers are not likely to be perfect, which it why you need to measure your own so you can see what pile of mismatched parts the previous rocket scientist left you. :mrgreen: If you want to complicate it even more...than OK work from the top of the spring but you probably then understand this little high school math exercise.

dynodave said:

I'll go back and edit my clutch article to make it lawyer correct since no one seems to catch the miniscule errors in language. I'll admit this above relationship was not "in your face" emphasized, But I never though it was all that hard to understand?

Click to expand...

I think DogT hit the nail on the head when he said: "I guess it takes about 10 times reading it and realizing what is going on."

As good as the information contained within the article may be (and I know you may not appreciate me for saying so, what with you not getting paid a penny to write it an' all) but the text tends to ramble in places so the information is perhaps not as clear and concise as it could be?

As: "A picture is often worth a thousand words", I think that the addition of a simple cross-section diagram of the clutch with all the necessary dimensions included (and perhaps a little less text?) would improve the article and perhaps make it clearer and easier to understand.

Those friction plates are toast. You asked about wear on the plates. The teeth can wear out before the friction surface itself. It would be good to see a picture of your clutch center and some of the friction plates. In theory, if the center is notched then the plates can hang up and make it hard to disengage the clutch. I've heard the theory but I've run my clutch down to one notched POS and it didn't mess up the action that I could tell. The teeth on the plates are not supposed to be pointed.

Robb2013 said:

the culprit?

Click to expand...

rpatton said:

In theory, if the center is notched then the plates can hang up and make it hard to disengage the clutch. I've heard the theory but I've run my clutch down to one notched POS and it didn't mess up the action that I could tell.

Click to expand...

A notched centre may cause a certain amount of clutch drag, but it wouldn't increase the amount of force needed to operate the clutch (which is the apparent problem here) as the clutch lifter mechanism only serves to release the spring pressure from the plate stack.

I haven't done much with this problem today, due to my energy still not being up to speed, but mostly just wanting to give it a rest for a while. There's a lot of little things going on: crud on the inner gears, stack low, plate seems not to bow in enough when relaxed, half ass lube job done on clutch cable. The inner gears crud really shouldn't make a rats ass of a difference as far as a hard pull goes because the pressure is being exerted outside of all the plates, on the pressure plate, and the crud is only on the inner portion of the gears. As far as stack height goes, that's a new one. I forget who made the suggestion of sticking some paper or something in there to raise the height and see if that changes anything... which sounds like an easy and possibly productive experiment. I have to admit, the clutch cable was a little bit stiff... I'd seen worse with no effect on other bikes, but I did give it a good soaking in silicone lube so when I hook it up again I can eliminate that as a possible problem.

Anyway... got my master cylinder rebuild kit in the mail today. The beagle chewed up one of the rubber bushings while I was out of the room for 5 minutes. Luckily it was only one of the 2 dollar parts so next time I order something from OB I'll throw it in the mix. I really didn't pay much attention to the master cylinder when I pulled it all apart. Today when sorting it all out to see what the extent of the beagle damage was, I noticed that the piston was pretty badly scored on the sides. I had stuck my finger down in the cylinder back when I pulled it apart and it felt nice and smooth in there. But with this scored piston I thought, how can that be? So I stuck my little finger way down in there until I felt roughness on the cylinder walls. Sooooooo I guess that means my master cylinder is toast. Here's a pic of the piston:

I wonder if we shouldn't start another thread on the "clutch pack height" and "clutch adjustment" and let Rob off the hook here. I've been thinking about this for at least 6 months or more since people seem to go back and forth on the issue and I seem to have a small issue with my adjuster to rod clearance. I'm sure DynoDave has his facts together, but it's rather hard to understand for a non- mechanic and one not well versed in the clutch operation other than using it. I'm just a Norton enthusiast. I'm even tempted to pull my diaphragm out and measure the pressure at different weights vs. spring deflection, but I'm sure DynoDave has already done that. Like L.A.B says, it would be very instructional to see a side section of the clutch and the various measurements. I would be willing to make an effort at resolving this issue and put it to rest. I would think if we can get all the pertinent information at hand, it can be resolved.

Dave
69S

DogT said:

I wonder if we shouldn't start another thread on the "clutch pack height" and "clutch adjustment" and let Rob off the hook here. I've been thinking about this for at least 6 months or more since people seem to go back and forth on the issue and I seem to have a small issue with my adjuster to rod clearance. I'm sure DynoDave has his facts together, but it's rather hard to understand for a non- mechanic and one not well versed in the clutch operation other than using it. I'm just a Norton enthusiast. I'm even tempted to pull my diaphragm out and measure the pressure at different weights vs. spring deflection, but I'm sure DynoDave has already done that. Like L.A.B says, it would be very instructional to see a side section of the clutch and the various measurements. I would be willing to make an effort at resolving this issue and put it to rest. I would think if we can get all the pertinent information at hand, it can be resolved.

Dave
69S

Click to expand...

Whoa... don't "let me off the hook". We're just at the point of getting somewhere.