Author Topic: crankshaft shock-absorber spring  (Read 3342 times)

Offline emilios

  • A's Good Friend
  • ***
  • Join Date: Apr 2008
  • Posts: 97
  • Karma: 2
crankshaft shock-absorber spring
« on: 18.03. 2010 19:18 »
Hi
I just renew my crank spring on my plunger A10...the problem is that ive been given wrong spring(A10 swingarm)
What is the difference? lenght?
Will that be a problem?

Thanks
Emilios
1956 BSA A10 Plunger
1954 BSA B31 Goldstar Replica
1970 Honda cb750K0 project
Cyprus

Offline bl**dydrivers

  • Valued Contributor
  • ****
  • Join Date: Oct 2008
  • Posts: 267
  • Karma: 1
Re: crankshaft shock-absorber spring
« Reply #1 on: 19.03. 2010 14:38 »
i dont believe there would be a problem, because bsa used the same engine internals on both the plunger and swing arm models.  The only problem I can think of is the primary drive outer case is smaller on the plunger, if it fits then there shouldnt be a problem.

Perhaps someone who has a plunger and more experience than I could reply and help out.


Offline a10 gf

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Sep 2006
  • Posts: 3230
  • Karma: 57
  • West Coast, Norway & Alpes Maritimes, France
    • A10 GF
Re: crankshaft shock-absorber spring
« Reply #2 on: 19.03. 2010 14:52 »
Why you need a new one, spring lost tension? I'm just about to take off the cush drive here, can measure the spring if you need a reference.


Stand with
A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Offline emilios

  • A's Good Friend
  • ***
  • Join Date: Apr 2008
  • Posts: 97
  • Karma: 2
Re: crankshaft shock-absorber spring
« Reply #3 on: 19.03. 2010 17:00 »
I just wanted to replace it cause i bougth bike from England and i dont know what age is...
Yes please measure it for me..
Thanks
1956 BSA A10 Plunger
1954 BSA B31 Goldstar Replica
1970 Honda cb750K0 project
Cyprus

Offline RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 6483
  • Karma: 55
Re: crankshaft shock-absorber spring
« Reply #4 on: 20.03. 2010 01:54 »
Emilios,

I didn't see where anyone mentioned the part numbers for the two springs. Plunger 67-2062; swingarm 67-1136, according to my book.

Here are two links to the vintage-motorcycle.com site showing the two different parts. To me, it looks like a definate difference, with the 2062 a bit longer and made from partially flattened stock, while the 1136 is made from round stock. Now, does this make a difference in the way they work, I really don't know. Others here seem to think not but maybe they could explain further. I'm definately curious.
http://www.vintage-motorcycle.com/index.php?language=en&site=4&pid=11&id=4932&gesucht=true&suche=normal&suchstring=67-2062

http://www.vintage-motorcycle.com/index.php?language=en&site=4&pid=11&id=2768&gesucht=true&suche=normal&suchstring=67-1136


Richard L.

Offline emilios

  • A's Good Friend
  • ***
  • Join Date: Apr 2008
  • Posts: 97
  • Karma: 2
Re: crankshaft shock-absorber spring
« Reply #5 on: 20.03. 2010 16:50 »
My plunger had a spring just like 67-1136(shorter than the other) and the new one i but looks like 67-2062...
Looks like someone put the swingarm spring on my plunger
1956 BSA A10 Plunger
1954 BSA B31 Goldstar Replica
1970 Honda cb750K0 project
Cyprus

Offline a10 gf

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Sep 2006
  • Posts: 3230
  • Karma: 57
  • West Coast, Norway & Alpes Maritimes, France
    • A10 GF
Re: crankshaft shock-absorber spring
« Reply #6 on: 20.03. 2010 18:28 »
spring (approx):

45mm high (this one may be slightly compressed due to age).
Outer dia 60mm, inner dia 44mm (material thickness 8mm).




Stand with
A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4528
  • Karma: 41
Re: crankshaft shock-absorber spring
« Reply #7 on: 20.02. 2014 13:39 »

 I could've sworn I posted here earlier, from the phone-just thought I'd check its progress....nevertheless....
I came across this post as a result of a i-net search for a replacement for....67-2062

  If someone asked me why I need a new spring, I'd have to show...see attached piccie.(I hope)

  For reference purposes this spring minus custom gap measures big enough ID to go over the sleeves, x 5/16" (8mm), x far as I can tell, 1,13/16 - 1,7/8" in length....
  Plunger cush components look same as swingarm ones but in fact slightly physically different.
It's from the phone, so hope it works
Cheers, duTch.

ps - figured why it didn't happen earlier is the file was too big, accidentally changed the resolution *bash*

Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4528
  • Karma: 41
Re: crankshaft shock-absorber spring
« Reply #8 on: 02.03. 2014 11:54 »

Quote
  For reference purposes this spring minus custom gap measures big enough ID to go over the sleeves, x 5/16" (8mm), x far as I can tell, 1,13/16 - 1,7/8" in length....
  Plunger cush components look same as swingarm ones but in fact slightly physically different.

 Update on previous post,  figuring may as well keep the theme together.

 Even though I asked for measurements when I ordered by phone, the replacement spring is vastly different to the original  and measures,:-

0.303 wire  *conf*, ID 1.752", Long/high, 1.704"
~7.7mm wire,  "     ID-43.3,    long/high  44.5
(similar to a10gf, but slightly different but seems to work ok)

I feel is not long enough, and a sloppy fit diametrically (3.5mm),and apart from not seating well on the landings, could affect crank balance to a small degree.

What I meant with the measurements from previous post, was what I think the spring should in my opinion ideally be closer to, as below;
( wire- 5/16" ID-1.625 x 1,7/8" long,
in metric-
( wire- 8mm, ID- 41.5+mm, Length 47.5 mm.)

 Reason I needed a replacement was I had a noise at kickover, that I knew was cush related, but was running fine, so wasn't too concerned till the gear changes were a bit crunchy, so figured the springs needed adjustment- again...... good thing I checked.

Hope that's of help to anyone, cheers

Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia