Plunger clutch wobble, how much??

[Minto]

Well, I’ve just pulled all the primary and clutch bits off to replace some mismatched Cush drive parts, and was wondering if this is normal or whether I’ve got summat wrong. The clutch centre is very stable but there seems a lot of rock in the chain wheel. Hopefully the link works.
Any sage words or thoughts gratefully received.

https://youtube.com/shorts/fmlgDQl_B-0?feature=share

[muskrat]

G'day Minto.
Looks about normal to me. Mine has a tad less but not much and that's with new rollers.
Cheers

ps: why is that one cover nut on backwards?

[Minto]

Well spotted Musky, it’s a duff one that’s been codged onto a “wrong” screw, by a previous codger.
Cheers mate, think I’ll risk a ride tomorrow then.
This is what I had to do to repair the cover after it had too much wobble… thank god for chemical metal.

[muskrat]

G'day Minto.
That amount of damage would have been caused by the center nut coming loose. My replacement case had worse. Had to get 5 screw boss's welded.
Cheers

[Rex]

Blown-out screw bosses are endemic in many old bike engines. Goes back to the days when a primary case leak meant Mr Bodge doing the the screws up with a 6' scaffold pipe.

[Swarfcut]

 Close inspection of the chainwheel may show the outer track of the rollers to be displaced slightly forward or behind the face of the chainwheel centre. This can result in a tightness in the freedom of rotational movement between the chainwheel, clutch centre and thrust washer. Lateral support for the chainwheel is in theory to the outside edge of the thrust washer at the back, at the front almost the full face of the clutch centre. The width of the outer race of the roller track  compared to the clutch centre roller boss accounts for the wobble. together with wear to the thrust washer face and clutch centre thrust face, along with any wear to the front and rear faces of that outer track. A clutch measured at random showed some 20 thou difference between the width of the chainwheel track and the boss of the clutch centre, in effect the running clearance between centre and chainwheel, clutch disengaged.

 There needs to be some clearance, and in practice a small amount makes a big difference to the amount of wobble. As long as it does not catch the case, that's the best you will get. All debated in the Forum, together with clever schemes to change the rollers for a sealed race or even a solid bush. There are other possibles as well, but in terms of time and money, simple replacement with better parts is the easy option.

Swarfy
 

[Minto]

Cheers Swarfy, I think I’ve digested most of that, though it’s early for me and took a couple or five read thrus.
I don’t think I’m going to look for new parts just yet, and modifying what I’ve got is way above my skills, presuming that would require major machining work.
So, going to ride as is and check on it periodically. At least now I’ve got a video for comparison. Might even get a measuring stick out before I button up the case.

Replacement Cush parts are now on, what I had were pretty much all wrong apart from the sprocket.

[a10 gf]

My 6 spring showed 'quite some' wobble, did not matter, fine adjustment for even plate lifting (& good plates) is what's needed to make it work perfect.

[Minto]

This is completely doing my head in now!! Coming close to putting an ad for it as a project for someone with more time on their hands.
Clutch and everything back on, cut new gasket for the primary case, go to fit it and the case is catching on the clutch. Now, I’ve either built the case back up way too much or the main shaft is screwed, that’s my reckoning. If it’s the latter it’s getting parked up for the next ten years til I retire, when I’ll have time to do it.
 I’ve tried filing the repaired bits on the case back as much as I think it should need but it’s still catching so much that the case will not go on.
Anyone got a decent pic of the inside of a plunger primary case so I can reference the rough shape and size of those bits.
Thanks all

[muskrat]

G'day Minto.
Have a look here https://www.a7a10.net/forum/index.php?topic=16831.60
From page #5. It's the primary case not the cover that I had welded up but it should give an idea of how much to build up.
Cheers

[Minto]

Thanks Musky, I’d read all that, but missed those pics somehow. The pics of the clutch and primary chain show exactly how little space there is between the whole assembly and the casting. Brilliant mate, massive help. Looks like bit more filing should sort it. Fingers crossed.