A10 Crankshaft Cush Drive; Clarification sought

[orabanda]

Hi all,
I suspect my 56 Road Rocket has the wrong spring fitted. It has the correct 2 lobe cush drive.

can anyone confirm the following details:


Free (uncompressed) length of the correct spring

The length of the boss on the nut that butts up against the crankshaft assembly (from the inner face that bears on the spring).

Also, would appreciate the same dimensions for the semi-unit engine, as I might have components mis-matched.

Has anyone got a table of these items, and how they vary between models? would be very useful info for everyone.

Many thanks,

Richard

[duTch]

 The semi-unit(Plunger) one is noticeably different to the two swing-arm type ones, being stepped so the sliding sleeve slides over the inner bit that butts up to the inner sleeve, and the springs are different (I reckon s/a ones are shorter and fatter by a few mm)but not sure of the measurements which I have back at the ranch. . Hope thatthat's a bit helpful

[RichardL]

I just dug out my '56 and later SA version (67-1137, the shorter one) and it measures right around 0.450" from the spring seat to the end of the boss inside the spring. I thought I had a long version as well, but couldn't find it. Hope this helps a little. Draganfly's diagrams all on on page were very helpful in understanding this.

Richard L.

(By the way, if I'm posting more obsessively than normal, it's because my wife is visiting relatives out of town for the whole weekend. Hoping for sun tomorrow to ride my *ss off.)

[chaterlea25]

HI All,
I posted som photos of the primary setup in this thread
http://www.a7a10.net/forum/index.php?topic=9646.msg70166;topicseen#msg70166

Let me know if you need more details / dimensions

HTH
John

[RichardL]

John,

That's a weath of information you posted. Couldn't read it all right now, but plan to. Would you happen to have  an early (long) swingarm cush nut to measure for Richard's info?

Richard L.

[duTch]

 Just came across the new replacement spring measurements for my Plunger that I believe is a S/A spring:- ID;1.752" x Length; 1.705" (ID; 44.5mm x L; 43.3mm),
 The ('56>)S/A Nut I have p# 42-71 is much same as Richards measurements; 0.560" long x 1.621" dia.(14.29mm x 41.17mm)
 Can't find my old broken spring which I saw a few days ago, but from memory it is ~42 ID x ~47mm Long probably fall over it later


Seems there's four different part numbers for Cush Drive Nuts;
Plunger/Rigid(?)      67-2054
 54…………...            67-1098
 55…………...            67-1137
 56/57/'58 >……….. 42- 00 71
 

[chaterlea25]

Hi All,
I have added some new photos with measurements of B33 and 1960 A10 cush drive parts
to my thread on primary alignment
http://www.a7a10.net/forum/index.php?topic=9646.0


HTH
John

[duTch]

 Already saw it...and posted for where-to-buy details, also am glad you mentioned here; saved me looking for my measurements again....

[chaterlea25]

Hi Dutch,
The spring came from Autocycle Engineering, I dont remember the price
the number of turns are different on the new spring compared to the originals ?????
There are  different part numbers, depending on year/ model ???

49-53  B series part number is 66-1706

Late GS part number is 67-1136
which seems the same as late A10 ? according to
https://drive.google.com/file/d/0B15KinXkOBJPZ2xhOE96b3cycGc/view

 
John

[duTch]

 Thanks John, I cant remember if I did it before, but just looked at the other numbers, and came up with;

 Cush Spring;
’49-’53         67-2062
 Plunger         67-2062
’54 S/A*         67-2062

’55-’56 S/A      67-1136
 ’58            67-1136  ( From "Late Spares'', as per photo)

[duTch]

 

the number of turns are different on the new spring compared to the originals ?????

   Did you by any chance note down, (or remember) the number of winds, or the ID?

 From "A10 Crankshaft Cush Drive; Clarification sought" thread

That's good John, assuming it's (spring) 8mm wire, that'd make the ID ~42.8 which is much more ideal than the one I bought.

  cheers

[The pirate]

Great article guys, it shows how tricky an A10 is to work on because of all the variables in machining, parts and repro bits. Throw a Triumph made clutch into the mix and it gets even worse.

[chaterlea25]

Hi Dutch,

   Did you by any chance note down, (or remember) the number of winds, or the ID

Old springs are 3 1/4 turns
New are 3 3/4 turns
I'm sure I gave that info on the other thread ??

John

[duTch]

 

I'm sure I gave that info on the other thread ??

Yes, you did too- sorry my oversight, I knew I saw it somewhere; in your post of 30/10... ('10/30' for Statesiders ):-

 

Recently I bought a new cush drive spring to suit a late Gold star, this is longer and has 3 3/4 turns where as the A10 springs have 3 1/4 turns ?? The B33 spring (broken!!) also had 3 1/4 turns ????

 I found my old broken Plunger spring (right where I left it ), and it has the same full turns (3,3/4 end to end) as your new spring....my broken one was in the engine when I bought it ~'78, but that's not to say it's the 'original' one