Whitworth Fasteners?

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Dan1950 said:
So that would be a standard 5/16 x 18 thread?
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If I could get down my workshop I'd check this out and give more details
But I'm laid up at the moment
Hopefully if I'm wrong someone will chime in
 
If you haven't pulled a commando primary before there's a couple of things to watch on re assembly
Make sure the inner chain case is shimmed on the centre stud
Make sure you replace the tab washers on the inner chaincase or loctite or both
Always replace the mainshaft clutch circlip and check sprocket alignment
Throw away the clutch tab washer and use loctite instead
Also the workshop manual torque setting for the clutch is far too high
But I can't remember the setting now recommended
Also the the alternator stator absolutely must have the 8 thou air gap
Don't over fill with oil (ATF) when refill it
As has been mentioned before it's really not hard to change the layshaft bearing in the bike
Unless you want to strip the whole lot out to check the whole lot out (not a bad idea IMO) then maybe just change the bearing and inspect for other damage
 
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baz said:
If you haven't pulled a commando

No 24 tpi
Click to expand...
OK same as 5/16" SAE. I should be able to fabricate an effective puller with 5/16 SAE grade 8 bolts available locally. Depending on the hole centers I may be able to use my harmonic balancer puller.
 
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Dan1950 said:
OK same as 5/16" SAE. I should be able to fabricate an effective puller with 5/16 SAE grade 8 bolts available locally. Depending on the hole centers I may be able to use my harmonic balancer puller.
Click to expand...
Yep a bar with 2 holes for the 5/16 sprocket bolts with a threaded hole in the centre as your puller bolt
 
Dan1950 said:
OK same as 5/16" SAE. I should be able to fabricate an effective puller with 5/16 SAE grade 8 bolts available locally. Depending on the hole centers I may be able to use my harmonic balancer puller.
Click to expand...

Snap-on Store

shop.snapon.com shop.snapon.com

Whatever you use, apply moly grease to the push screw threads, and you'll also need to heat the sprocket to release.
 
EstuaryBoy said:
Blowtorch and Glasgow screwdriver (extra large) :)
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Something I was told years ago was when heating something round to release it you should only one spot because it expands and breaks it grip better than heating the whole thing with the resultant heatsoak into the shaft you are trying to remove it from?
 
baz said:
If I could get down my workshop I'd check this out and give more details
But I'm laid up at the moment
Hopefully if I'm wrong someone will chime in
Click to expand...

Yes the factory puller bolts are 5/16" UNF x 4.0".
Dan1950 said:
OK same as 5/16" SAE .I should be able to fabricate an effective puller with 5/16 SAE grade 8 bolts available locally.
Click to expand...


Unified has been the US thread standard since 1949.

United States Standard thread - Wikipedia

en.wikipedia.org en.wikipedia.org
"The USS standard is no longer supported. It, together with the SAE fastener standard, was incorporated into the Unified Thread Standard. However, the term, USS, continues to be used occasionally today to describe inch based threaded fasteners with a coarse thread pitch and inch based washers that are a little bit larger than the corresponding SAE washer. The Unified Thread Standard uses the term UNC (Unified Coarse) to describe a fastener that previously would have been designated USS and the Unified Thread Standard uses the term UNF (Unified Fine) to describe a fastener that would have previously been designated SAE."


Unified Thread Standard - Wikipedia

en.wikipedia.org en.wikipedia.org
"The Unified Thread Standard (UTS) defines a standard thread form and series—along with allowances, tolerances, and designations—for screw threads commonly used in the United States and Canada. It is the main standard for bolts, nuts, and a wide variety of other used in these countries. It has the same 60° profile as the ISO metric screw thread, but the characteristic dimensions of each UTS thread (outer diameter and pitch) were chosen as a fraction rather than a value. The UTS is currently controlled by ASME/ANSI in the United States."
 
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Dan1950 said:
Is there a tool for pulling the engine sprocket?
Click to expand...
This will be the hardest nut to crack, taking the sprocket off that is. You want a robust puller and hydraulic is best, even then heat and a sharp belt with a copper mallet will be needed. That taper gets a tight grip on the sprocket.
 
Dan1950 said:
I am planning on purchasing or fabricating tools to remove the entire primary drive.
Click to expand...
Then you need to locate the lock ring.....and you will need a tool unless you favour a centre punch....but as a clue the lock ring isn't on the primary drive side.....
 
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