I know/think something is wrong.

[a10 gf]

^^^

I don't believe you can fit a cotter pin with that nut

Ahhh... then maybe a good move is finding a way to fit one?

[Topdad]

Hey managed to remember something !! Bob

[duTch]

 Yep I was going to say 65 also, as I found it written somewhere the other week when I did my cush spring, but only could get it to ~55-60 before the clutch slipped...!

 Also, I found a nice hardened washer just the correct thickness to fit between the nut and split pin- just had to chamfer the inside to accommodate the dish of the nut.
 Can't see why it shouldn't work ok...?

 Now I think I understand what those two chamfered notches are for on the spare ~'58 nut I have, the plunger doesn't have them....

[RichardL]

^^^

I don't believe you can fit a cotter pin with that nut

Ahhh... then maybe a good move is finding a way to fit one?

I think it might require castellation, but I wouldn't want to try to get an extra 57 or 58 degrees of turn after reaching 65 ft.-lb. SRM says it won't let go at 65 ft.-lb., but a little Loctite seems some good insurance.

With regard to clutch slipping, I have gotten around that by tightening the hell out of the clutch nuts. Better way, I understand, is with a clutch locking plate.

Richard L.

[Ethelred]

Yep I was going to say 65 also, as I found it written somewhere the other week when I did my cush spring, but only could get it to ~55-60 before the clutch slipped...!

That's interesting. Is there a figure for how much torque you should be able to apply before the clutch slips? That would be invaluable when adjusting the clutch, save having to pull it all down again just coz you didn't get the springs tight enough.

[bsa-bill]

Is there a figure for how much torque you should be able to apply before the clutch slips?

that's a double sided equation Ethelred as it depends also on the load ( - riders weight- incline of road - head wind) v engine torque
 plus other factor tyre grip so forth, I think there is not a lot to be gained by trying to get too near slipping point.

You might just get the impression I'm in a pedantic sort of fettle to day

[Angus]

Yes I have now read elsewhere tighten to 65ft/lb and have also seen a nice picky of a socket with ears on to do it up as the nut is fine, See
http://www.a7a10.net/forum/index.php?topic=556.msg3103#msg3103
It did not have the loc washer so have order one.

As A10 out of commission been out on the A7 ALL DAY 


 

[chaterlea25]

Hi All,
Ignoring the twaddle about cotter or split pin definition,
In Angus's photo of the loose nut the remains of the pin can be seen in the crank end
so the nut chewed its way through-over the pin
The method I use to keep th nut in place is not bother with lockwasher or pin and use loctite (nutlock)
and tighten to 65ft lbs, I have made a locking tool from two old clutch plates bolted together and onto a longish handle

Angus,
If the bike has been running for a while with the nut loose, quite often the crank shims will make a bid for freedom 
While the assembly is undone check crank end float, and look for any mettalic debris in the sump filter

Hope it all goes well
John

[RichardL]

If the bike has been running for a while with the nut loose, quite often the crank shims will make a bid for freedom 
While the assembly is undone check crank end float, and look for any mettalic debris in the sump filter

Yes, this is the missing link in the advice chain. Bits'o'shim was the reason for my current rebuild, though due to a loose main bearing inner race. Not to be confused, I'm sure John meant "laying on top of the sump filter."

Richard L.

[muskrat]

Lucky 
Yes 65ft/lb is the magic figure. It is very important to have it locked up TIGHT.
I have an SRM hex type on the cafe and a standard on the '51. Neither have ever come loose with the use of loctite. With the std one I make washers/shims to go behind the split pin so the nut can't turn/loosen at all. There is a tool that fits the std nut and allows the use of a tension wrench.
http://www.ebay.com.au/itm/BSA-GOLDSTAR-A10-A7-B31-B33-CRANK-NUT-TOOL-/181375692429?pt=UK_Motorcycle_Parts_13&hash=item2a3ad56e8d
I don't know how strong it is (if the teeth strip off on first use).
Cheers

[Angus]

Well John (chaterlea25) the end float shims thing really scared me.

The major reason the A7 was off the road for approx 30 years was end float. I found the remains of the shims in about 1978 and pulled it apart and rebuilt it (the second engine I ever rebuilt). Then in 1982 there they where again, so I pulled it apart and I can not even remember how may times I tried to do the end float. I spent a lot of money on new chrome on the tank and paint, new wheel rims, new exhaust, stoved frame etc. But I just could not get the engine end float right.
So into boxes it went   .
Back to the A10 and subject
I have dropped the sump plate (with much worry) and no sign of any bits there (magnetic plug on sump plate). There does appear to be some end float but can not measure as only got primary off (can hear it rather then feel or see it). I had the sump plate off 250 miles ago when doing oil change and there was nothing there then either

So please can I put it back together now  .

Here is the plan. I will use a tab washer (ordered) loctite and a pin (a fatter one as the old one was a thin little thing). I will do it up to 65ft/lb.
Then I will ride her (or rather my son will mostly) for the summer, probably only a couple of thousand miles. The next winter I will pull her apart a bit more and check out how things a wearing. 

[KiwiGF]

If it helps, when I rebuilt my A10 I asked the engineer to set the end float and he made a thick shim rather than several thin ones to get it right, but when I put it back together and withe bottom end in the frame I noticed a definite clunk and movement when checking the end float and for a while I thought he had got it wrong, but when I measured it with a dial guage the actual end float was less than 002, you could measure yours before pressing on but from what you have said the chances are the end float you have is within limits 

[chaterlea25]

Hi Angus,
It sounds like (pun) that your crank is OK
Attached is a pic of the homemade locking "tool" I use to lock the crank and clutch so as to torque up the crank nut properly
I dont believe in stripping down a well running engine to look for trouble, a careful eye on performance /noise and oil tells a lot

"If it aint broke"

John

[RichardL]

I dont believe in stripping down a well running engine to look for trouble, a careful eye on performance /noise and oil tells a lot
"If it aint broke"

That John is full of good advice.

Richard L.

[bsa-bill]

you been in my shed John? that tool's a lot like mine  - great minds eh