Author Topic: crankshaft shock-absorber spring  (Read 2489 times)

Offline emilios

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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

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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 a10gf

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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.

A10 GF '53 My A10 website
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Offline emilios

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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

Online RichardL

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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.
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Offline emilios

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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 a10gf

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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).



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

Offline duTch

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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

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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