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Did you get your end plate off the center? If so what does the end plate and spider look like?

Has something been chewing on my rubber?

Too late now, the countersunk screws have the threads punched, this has to be drilled out before they unscrew. Hope you ordered new cush rubbers as well, Ive seen worse , at least yours havent dissolved. pretty typical end plate wear , the spider will have lost a similar amount. ive hear of folks turning the end plate over and redrilling holes, but never done it myself.
The wear shown in the pic has a nasty effect, the spider is fairly well fixed square to the mainshaft, the inner slotted drum relies on the close fit of the spider between its end plates to stay true, as the wear develops the slotted drum tilts under load, result slipping clutch and a tortured primary chain, folk try to fix this with new plates and springs oblivious to the real culprit. Once the spider starts showing through the back of the endplate by a significant amount then its all over bar the shouting.

Well said Gavin, end plate, spider, and Cush rubbers are toast. The rubbers deteriorate over time due to they are housed in a very harsh environment, extreme pressure, heat and oil. How does the other end plate look?On the bright side, replacing all the parts you will have ordered you should be good to go.

I've gotten a lot of great information here.
But can someone PLEASE tell me do these marked areas clamp together on assembly and make contact, yet still allow the centre to turn freely as it should and mine doesn't?

The areas shown should not clamp together, possibly , as Sam IIRC suggested earlier the outer bearing race marked in the top pic is protruding into the inner drum, some checks with leads/ solder/ bearing fit, paper , anything would help, it does look proud in the pic, this should not be tight to the inner drum, it usually has generous clearance. The inner face of the spider stops against the hub to set the end play on the bearing, there is usually enough clearance to create "wauchle" at the basket OD , you have something out of whack, the fecked hub isnt helping, I strongly suspect this , its certainly fecked , who knos what else has been done to it ,
if the bearing race has moved towards the clutch then that would definitely spoil the party.
First get a new hub, most of the big issues are right there, this might fix your binding problem , check/ press the race into position ,that and a fresh cush drive..Who knows what was put in there before.

"But can someone PLEASE tell me do these marked areas clamp together on assembly and make contact,"

NO, they do not/should not. In further suppport of what Gavin is saying: In the picture, where the splines on the hub "end", you'll see a thin shoulder, just inside the rollers (not labeled). That thin shoulder is what stops the clutch center from going onto the hub any farther, and SHOULD protrude out farther than the "X'ed" area on the clutch basket. Again, if it does not, something is wrong with your clutch hub or the basket is the wrong part, but more likely the hub. It could also explain why the hub seems to be going too far onto the mainshaft.

If there were damage to the mainshaft taper, I think you would see evidence of that.

You may need the end plate and spider, and the cush rubbers definitely need replaced, but I don't think this is causing the binding. I've run clutches with grooved end plates and it did not cause binding.

Aha! The shoulder on the hub! I get it! It's like a light going on. Now I see how these parts should work together. Thank you!
Amazing the engineering on these bikes.
I'll play with it some more and try to see which part or parts is out of whack.

Gavin, I had heard the screws were punched but I could not see it. Not like the punch on the sludge trap anyway.
But you said the threads were punched. How is that done?
And what is "wauchle"?

Also looks like someone has tried giving that back plate a new lease of life before as it looks like its been flatted off but inevitably ground away again. most likely due to the wear on the rubbers.

Use the old hub and grind 2 flats on the flange, quite big ones infact. Then you can mount it into a vice, and with an old plain clutch plate with a bar welded to it, you can assemble the under side of the cush drive, fit one set of rubbers (thats the easy bit) then apply squashing force using the modded clutch plate to create enough space to drop the other rubbers in.... Easy enough if you have the right tool..... Completely impossible if you do not although you may be able to remove and refit the old rubbers with a screw driver.... the new ones wont go in like that.

If you haven't already done so, it often works out almost the same price buying a new cush drive unit with all new bits in that it does replacing those parts alone.

On the cush hubs I have fiddled with the threads at the rear were "staked" so the screws could not loosen. Sometime a centre punch mark, sometimes the thread end is mushroomed/ rivetted.
Wauchle = wobble, the clearance at the hub bearing usually allows a quite alarming amount of free play at the basket rim, dont worry about this its normal.

Nick, your pissing in the wind trying to salvage knackered 40 year old parts. The screws falling out of the cush drive became such a common problem that the factory redesigned it. They did not spend money lightly! The updated version has through bolts to prevent the issue, if your going to spend your money, spend a little more and fix a problem before it becomes one.

Rod

I keep hearing that! I must be all wet!

I'll get there. Thank you all for your patience with me.

New hub and new spider arrived. Same issue.

The new hub does fit better on the shaft but I still get the centre binding when tightened up.

At least now I understand how the parts are supposed to fit. I just don't know why they don't. Pissing downwind.

Note the witness marks.

Then I tried it without the thrust washer and while the centre now moved.. ok ..with the nut fairly tight, the witness marks returned, fainter.

Waiting on a new end plate - my last hope?

Is the race pressed into the basket flush on both sides of the basket? Looking at your bottom picture It appears not to be flush. Did you fasten the end plate to the center with the three screws and rubber cushions in place?

Could you post a picture of the back side of the basket showing the race?

Sam, Yes, the inner circle is the race for the bearings and at your previous suggestion I pressed it in just a hair so that it is now flush on the back side.
On the side shown in the photo it is slightly lower than the outer ring which is where the binding is happening.

Here's the back side. I know photos can be decieving but the bearing is flush here.


And, no the centre has no rubbers and one screw holding it together, but I can't see how that will matter.

Something must be seriously amiss. As Gavin says there should be "generous clearance". And there should be a bit of wobble.

The race in the chainwheel is supposed to be flush to the face on both sides. Your picture of the plate side appears to be proud. One here measures 0.238 thick.

If you have a micrometer measure the width of the area that the race is pressed into, it should be around .240

Ok, just reread your last post and if I’m reading it correctly you state the race is flush on the backside of the basket, that’s good. You also say the race is recessed a little on the clutch plate side, it should be flush and this is probably where your problem is, that’s why I asked you to measure the width of the area the race is pressed into and measure the width of the race also it should be .240 or close to it. I have measured a new basket here and that is the reading I get. Looking at your basket on the backside I don’t see a part number cast into it which tells me it might be an offshore part. Most baskets that are nos or nors made by lf Harris have a name or number on it. Thus quality control could be an issue on these types of parts.

I'm getting .243" for the inner race and .265" for the outer circle where the binding is happening. Could this be it?

Yep, I believe you’ve found your problem, you’re about .025 wider then you should be. Whom ever machined that basket apparently didn’t finish the job. Don’t ever recall seeing that before, I have seen the race in the basket come loose but that’s rare. Well I guess it’s decision time, another basket or machine, grind the binding area down.

How does the hub fit on the main shaft without the key in place?

I haven't look closely as I've been chasing the other issue but I did check and saw that it doesn't slide on as far as the old one (without the key in place).

Lots of Emgo, Taiwan sproket baskets out there. Probably what I have. Hesitant to try another although mine is probably a fluke. I'm thinking to buy UK made.

When I was running the standard setup on mine, I had one of the balanced Dural alloy baskets on, they get a lot of bad rep but to be honest I found that as long as you shimmed the sprocket properly so that it lined up properly with the basket (which you should do regardless) then I never saw any wear on it. I got mine from Burton Bike Bits, but I beleive Norman Hyde does the same item.

Nick, if you PM me with your number I’ll give you a call.

Sam