Weird clutch

[RDfella]

I see Bill's alarm - but closer inspection appears (to me) to indeed be the camera angle causing the effect.
As for the keyway in the shaft, only thing to do is try to dress the burrs a little with a small file. Otherwise, it ain't too bad ....
I'd still lightly lap it with valve grinding paste, though.
Chainwheel - yup, a bit distressed but it'll run a while longer. Just check sprocket alignment.

[groily]

Really hope RD's right worty. Try fitting the centre after de-burring and see if it goes on snugly without the key. The taper is the bit that needs to do the work, after all.

[Worty]

Trying to think if the taper can be 'dressed' with something in situ?  One thing is for sure, all the force was being carried by the key and not the taper.  Thoughts that spring to mind is whether a thin piece of metal can be inserted into the clutch centre with a space for a new key, then belt up the nut with plenty of torque and Loctite. 

Just go horrible thoughts of new chainwheel, clutch centre, mainshaft, etc - Yikes  

[Worty]

Really hope RD's right worty. Try fitting the centre after de-burring and see if it goes on snugly without the key. The taper is the bit that needs to do the work, after all.

I can try, but I don't understand why it seems to grip when rotated - unless either the shaft or the centre hole is worn unevenly.  Where the key lines up, the centre is loose on the shaft, rotate it about 20 degrees and it tightens a bit.  I'm fearing this may prove to be costly, unless I just get a new key and Loctite everything.

[RDfella]

Thoughts that spring to mind is whether a thin piece of metal can be inserted into the clutch centre with a space for a new key, then belt up the nut with plenty of torque and Loctite. 

Absolutely not! Might get away with that when fitting a boat propeller that's too big for the shaft, but not in this case. Apart from the fact there's no need.

[Worty]

Thoughts that spring to mind is whether a thin piece of metal can be inserted into the clutch centre with a space for a new key, then belt up the nut with plenty of torque and Loctite. 

Absolutely not! Might get away with that when fitting a boat propeller that's too big for the shaft, but not in this case. Apart from the fact there's no need.

Don't worry RD, I'll try the deburring first, but it does seem that if the centre isn't tightening on the shaft now, I can't see how it would improve things after taking the burrs off

[Worty]

Just a thought.  If the tapers are no good after deburring, is it possible to fabricate a Woodruff key to the same length and width but with a bit of extra height which would help the centre grip the taper better by 'jamming' it up??  This would be the opposite to CB's suggestion, but I'm guessing his would be a solution where the key was interfering with good tapers?

If all of this is out of the question, maybe my next port of call is a decent s/h box??

[JulianS]

I think you need to establish if it is a damaged shaft or a damaged clutch centre or both, perhaps by trying a different clutch centre on your mainshaft?

[Worty]

Cheers Jules, it'll be a case of locating a spare centre though.

[chaterlea25]

Hi Worty
The shaft keyway looks fairly buggered 
This will have raised the metal fractionally on either side of the slot
You have not shown us what th inside of the shaft adaptor looks like? Is it as bad?
So, file either side of the shaft keyway a touch to get rid of any high spots the same with the adaptor
Them lap the adaptor to the shaft, just a touch at first, look for any high spots, file these down and repeat
If you get maybe 75% contact I would be happy enough
Attempt to make a stepped key that is as tight as possible in the shaft and adaptor, measure the adaptor keyway slot and make the top half of the  key a little less than this so it has a better chance of staying straight, too high  and the adaptor will not seat on the shaft
It might take a few attempts to get the key as good as possible 

Alternatively, If you can get the taper to 75% or so contact I would use Loctite 648 retainer grade without any key
and tighten the nut to fully FT
It is also possible to change the gearbox mainshaft without a complete gearbox strip, It takes a bit of care but it is possible

The clutch chainwheel is not running in line with the crank sprocket or has been in the past
I posted a thread about this some time ago,, 
https://www.a7a10.net/forum/index.php?topic=9646.msg70166#msg70166

John

[Worty]

Ok, I realise I may incur the wrath of people on here, but here goes.  I discovered, after deburring the keyway (which is pretty knackered), that the adapter is loosest where the keyway is in line with the recess on the adapter.  Turning either side of this tightens a bit.  This led me to conclude that, if the adapter is tight on the shaft where the keyway is, then the rest will tighten up on the taper as it's pressed on.  So, I made a new key that, when tapped into the keyway, is tight on the adapter to the point it couldn't be simply pushed on.  I then used the nut and spacer/washer, to press the adapter on before removing the nut to see if anything moves (which it did before).  The whole thing was solid as a rock with no movement of the adapter on the shaft.  Given that the whole thing was dripping with Loctite prior to application, and that the nut will have the same treatment, I'm hoping that it won't be coming loose anytime soon.  I will, however, need to purchase an extractor if it needs to come off again in future.

As for lining up the chainwheel with the sprocket, how do you adjust if it's not in line (not that mine appears to be now it's tightened up).  My theory is that as the clutch came loose, it wasn't lining up with the sprocket and caused some of the wear issues on the chainwheel.

[berger]

worty a few pics of my box shafts with a good dose of blue to make seeing better, so you need to compare with yours. the first is rrt2, 2nd spare rrt2, 3rd standard for the berglar build and 4th spare std shaft

[muskrat]

G'day Worty.
Wear on the sprocket could also be caused by motor to gearbox misalignment, see  https://www.a7a10.net/forum/index.php?topic=9646.msg138795#msg138795 and here  https://www.a7a10.net/forum/index.php/topic,2689.msg17652.html#msg17652
While it's all apart take the inner primary cover off and do a few checks.
Cheers

[Worty]

G'day Worty.
Wear on the sprocket could also be caused by motor to gearbox misalignment, see  https://www.a7a10.net/forum/index.php?topic=9646.msg138795#msg138795 and here  https://www.a7a10.net/forum/index.php/topic,2689.msg17652.html#msg17652
While it's all apart take the inner primary cover off and do a few checks.
Cheers

On checking, and as Musky says, there is a motor to gearbox misalignment.  Engine sprocket is appx. 3.5 - 4.00mm out of line with the chain wheel measured with the straight edge of a hacksaw blade and a vernier.  So, chainwheel could do with 'coming out', and/or engine sprocket 'going in', so to speak.  I'm guessing that the only 'adjustment' to be made is via the gearbox, unless there is scope to push the engine sprocket in a bit (not sure about chain clearance on that one).

It's been like this since I've owned the bike and explains why the inner side of the chainwheel teeth are polished and worn inwards, and why there's a 'notch' on the teeth 'leeside' (chain pulling against the teeth).  Will probably explain why the chain has some tight spots too.

So, any chance of shoving the gearbox over a few mm.  I could also try Musky's suggestion of loosening the gearbox and moving it backwards and forwards to see if it reseats in the right place??

I know there's stuff on the Forum, but a succinct summary of suggestions here would be really helpful.

[CheeserBeezer]

The alignment is usually achieved with shims behind the drive gear sleeve, but the amount yours is out of alignment would suggest something else is wrong. I suspect you may have the incorrect drive gear sleeve or the sleeve inside the oil seal is too thin.