Mainshaft Spline Extension through Sleevegear

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robertv

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Hello all. My first re-assembly of a '74 Commando gearbox. I have three. The first pic is a good used box that shows some mainshaft splines extending out. The second is the box I want to re-assemble. Splines just inside the sleeve gear.
Third pic is an ebay box that came filled with water. No splines extending out. I have used a drift to make sure the bearing is fully home in the case. My question is: how critical is this extending of the splines of the main shaft.
Sadly I am not able to insert photos. Is this distance critical to the box operating correctly? Thankyou.
 
Sounds like a bunch o' issues here .
Do not knock a bearing home ito a case without a heat gun .
No photos . ?
 
Torontonian said:
Sounds like a bunch o' issues here .
Do not knock a bearing home ito a case without a heat gun .
No photos?
Click to expand...

Torontonian said:
Sounds like a bunch o' issues here .
Do not knock a bearing home ito a case without a heat gun .
No photos . ?
Click to expand...
The unopened box is factory. The second box was built by a machinist who was unable to access 1st gear and tore it down and I bought it as parts. All cleaned. He installed the bearing. I suspect he was a tooth off with gear selector. Third box never torn down before me. OG bearing never removed. How much do these splines need to extend out from the sleeve gear.? Or don't they as long as the gear is fully home. If the bearing inner spacer was shorter, then all would be good, except possibly the lineup with drive sprocket. Still learning here.
 
robertv said:
How much do these splines need to extend out from the sleeve gear.?
Click to expand...


The mainshaft has to extend far enough to fit the clutch location circlip in the mainshaft groove after the inner primary case is fitted and other clutch parts including the clutch centre.
andover-norton.co.uk

Andover Norton - CLUTCH LOCATION CIRCLIP (MAINSHAFT) - 06.0752

CLUTCH LOCATION CIRCLIP (MAINSHAFT)
andover-norton.co.uk
robertv said:
Sadly I am not able to insert photos.
Click to expand...

You can if you use a photo hosting website such as https://postimages.org/ or you can become a VIP member.
 
A post using postimages, are you sure they are Commando gearboxes ? when removing or reseating bearing in an AMC box the case has to be hot enough for water to sizzle and steam off. There is very little support between the bearings and not much more around them, once they are fully seated do not bang them any more or the case will crack.

Mainshaft Spline Extension through Sleevegear
 
Last edited:
robertv said:
The second is the box I want to re-assemble. Splines just inside the sleeve gear.
Click to expand...

That makes no sense as how are you going to fit the clutch? Plus the mainshaft extends through the bearing in the inner cover on the right hand side so how can the splines be no further than inside the sleeve gear? Something sounds wrong there.
 
robertv said:
My question is: how critical is this extending of the splines of the main shaft
Click to expand...
I think you’re asking the wrong question. What you should be asking is “is my gearbox assembled correctly, or do these pictures indicate a problem.”

Someone more experienced than me may be able to diagnose based on those, but I can’t. Instead, I’d recommend disassembling and then reassembling the box in the correct way according to the manual. In particular;

1. Measure the bearing to ensure it is the correct width and make sure it is fully seated.

2. Install the sleeve gear and ensure it is fully inserted into the bearing. If you’re using the relationship between sleeve gear and main shaft to diagnose a problem, you need to be sure the gear is located correctly.

3. Assemble the rest of the box and torque the nut on the timing side of the main shaft.

4. Only install/worry about the sprocket and sleeve gear nut after you’re done with the rest of the box.

This assumes you’re torquing the sleeve gear nut with an end wrench or super deep socket, the main shaft will get in the way of a regular socket.
 
Hammerski said:
I think you’re asking the wrong question. What you should be asking is “is my gearbox assembled correctly, or do these pictures indicate a problem.”

Someone more experienced than me may be able to diagnose based on those, but I can’t. Instead, I’d recommend disassembling and then reassembling the box in the correct way according to the manual. In particular;

1. Measure the bearing to ensure it is the correct width and make sure it is fully seated.

2. Install the sleeve gear and ensure it is fully inserted into the bearing. If you’re using the relationship between sleeve gear and main shaft to diagnose a problem, you need to be sure the gear is located correctly.

3. Assemble the rest of the box and torque the nut on the timing side of the main shaft.

4. Only install/worry about the sprocket and sleeve gear nut after you’re done with the rest of the box.

This assumes you’re torquing the sleeve gear nut with an end wrench or super deep socket, the main shaft will get in the way of a regular socket.
Click to expand...
All good points. My thought was that I will be building the box around this gear/shaft assembly.
If I have issues it will be easy to disassemble if necessary.. Thanks for your reply.
 
I can't see the problem with the mainshafts that you mentioned unless I misunderstood what you meant. The spacer appears to be missing from the gearbox on the right in the last picture also note that the flat side of the nut faces to the outside and the curved/chamfered side to the sprocket.

andover-norton.co.uk

Andover Norton - GEARBOX SPROCKET SPACER - 04.0131

GEARBOX SPROCKET SPACER
andover-norton.co.uk

To post individual photos use the 'Hotlink for forums' option.
Mainshaft Spline Extension through Sleevegear
Whichever gearbox you rebuild be sure to change the layshaft drive side ball bearing for the roller bearing if it has not been done especially the '74 box as that could have the failure prone Portuguese brass cage ball bearing in it although it should be changed in any Commando gearbox.
andover-norton.co.uk

Andover Norton - LAYSHAFT ROLLER BEARING (18337) (B2/322) FAG Schaeffler - 06.7710

LAYSHAFT ROLLER BEARING (18337) (B2/322) FAG Schaeffler
andover-norton.co.uk
 
Last edited:
L.A.B. said:
I can't see the problem with the mainshafts that you mentioned unless I misunderstood what you meant. The spacer appears to be missing from the gearbox on the right in the last picture also note that the flat side of the nut faces to the outside and the curved/chamfered side to the sprocket.

andover-norton.co.uk

Andover Norton - GEARBOX SPROCKET SPACER - 04.0131

GEARBOX SPROCKET SPACER
andover-norton.co.uk

To post individual photos use the 'Hotlink for forums' option.
Mainshaft Spline Extension through Sleevegear
Whichever gearbox you rebuild be sure to change the layshaft drive side ball bearing for the roller bearing if it has not been done especially the '74 box as that could have the failure prone Portuguese brass cage ball bearing in it although it should be changed in any Commando gearbox.
andover-norton.co.uk

Andover Norton - LAYSHAFT ROLLER BEARING (18337) (B2/322) FAG Schaeffler - 06.7710

LAYSHAFT ROLLER BEARING (18337) (B2/322) FAG Schaeffler
andover-norton.co.uk
Click to expand...
Thanks for your input. Greatly appreciated. Robert
 
L.A.B. said:
I can't see the problem with the mainshafts that you mentioned unless I misunderstood what you meant. The spacer appears to be missing from the gearbox on the right in the last picture also note that the flat side of the nut faces to the outside and the curved/chamfered side to the sprocket.

andover-norton.co.uk

Andover Norton - GEARBOX SPROCKET SPACER - 04.0131

GEARBOX SPROCKET SPACER
andover-norton.co.uk

To post individual photos use the 'Hotlink for forums' option.
Mainshaft Spline Extension through Sleevegear
Whichever gearbox you rebuild be sure to change the layshaft drive side ball bearing for the roller bearing if it has not been done especially the '74 box as that could have the failure prone Portuguese brass cage ball bearing in it although it should be changed in any Commando gearbox.
andover-norton.co.uk

Andover Norton - LAYSHAFT ROLLER BEARING (18337) (B2/322) FAG Schaeffler - 06.7710

LAYSHAFT ROLLER BEARING (18337) (B2/322) FAG Schaeffler
andover-norton.co.uk
Click to expand...
I just took a portuguese brass case layshaft bearing out of a mk 2 850 gearbox last week so there are still some out there.
 
ilikevelos said:
I just took a portuguese brass case layshaft bearing out of a mk 2 850 gearbox last week so there are still some out there.
Click to expand...
I ordered a new Norton 21 tooth drive sprocket from a reputable British bike shop. It is very nicely made. I had to heat it to install it. It is the correct width at 3/8". The sprocket I tried to use previously was thicker. Perhaps aftermarket.? Now, everything looks right. I had to polish the mainshaft and the new bushings The clearance feels just right with a little oil. To those of you who offered help and advice, I am most grateful.
 
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