Author Topic: a7 STAR tWIN CONRODS: "small" or "large" journals?  (Read 1504 times)

Offline bikeaholic

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Hi, I recently joined this forum.  I have a '52 A7 Star Twin (plunger) and need to acquire a pair of conrods - does anyone know if I should be looking for "small" or "large" journal conrods?
Thanks!
Haven't got a clue, in Surrey...

Online muskrat

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Re: a7 STAR tWIN CONRODS: "small" or "large" journals?
« Reply #1 on: 21.05. 2010 21:36 »
G'day bikaholic,
                           A7's only have small journal cranks and rods. The large journal was for A10's '58 onwards I think.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline A10Boy

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Re: a7 STAR tWIN CONRODS: "small" or "large" journals?
« Reply #2 on: 25.05. 2010 21:20 »
Correct.
There were some NOS on ebay recently.
Regards

Andy

1960 A10 - Black Golden Flash
Plus
1974 Kawasaki Z1a
Yam XJR 1300

Offline bikeaholic

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Re: a7 STAR tWIN CONRODS: "small" or "large" journals?
« Reply #3 on: 03.06. 2010 09:44 »
Ok thanks for that...
The next question is will conrods from a 54 or later A7 fit my '52 Star Twin? Is the only difference the inclusion of an oil hole in both rods (and all shells) as opposed to in the left rod only in the earlier version, or are there differences in the journal diameters and big/small end centres?
As you will have gathered, by basket case lacks conrods!
Cheers!...

Online muskrat

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Re: a7 STAR tWIN CONRODS: "small" or "large" journals?
« Reply #4 on: 03.06. 2010 13:31 »
Yes, but oil hole in left only. That was a bit of a issue on another topic.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline bikeaholic

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Re: a7 STAR tWIN CONRODS: "small" or "large" journals?
« Reply #5 on: 03.06. 2010 22:35 »
Hi Muskrat,
Thanks for replying to my posts...
So I can go ahead and put '54-'62  A7 conrods in my '52 A7?
 When you said "yes, but oil hole in left only" do you mean that the '54 on conrods only have one oil hole per set?
Is there an earlier related thread I should be reading?...

I'll likely be asking loads more questions about my missing bits, so thanks for your patience!...
Cheers, Ken.

Online RichardL

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Re: a7 STAR tWIN CONRODS: "small" or "large" journals?
« Reply #6 on: 03.06. 2010 22:45 »
Ken,

I guess it's just a matter of how much you can stand. The following two topics are part of the discussion.


http://www.a7a10.net/forum/index.php/topic,2612.20.html
http://www.a7a10.net/forum/index.php/topic,1499.0.html

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Online bsa-bill

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Re: a7 STAR tWIN CONRODS: "small" or "large" journals?
« Reply #7 on: 04.06. 2010 09:22 »
IF you've waded through those posts you will have maybe come to a decision, however if memory serves ( HA ) are the two hole rods not A50/65
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline bikeaholic

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Re: a7 STAR tWIN CONRODS: "small" or "large" journals?
« Reply #8 on: 04.06. 2010 11:07 »
Hmmmm....
Thanks for the responses.
I have reviewed the postings suggested, and the expression "can of worms" springs to mind!
I suppose I had better wait for 1952 spec conrods to turn up, or cough up about £300 for a set of new "SMP"(?) rods...

Offline trevinoz

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Re: a7 STAR tWIN CONRODS: "small" or "large" journals?
« Reply #9 on: 05.06. 2010 10:23 »
Any A7 rods except the early long stroke type will suit your engine.
          Trev.

Online Brian

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Offline bikeaholic

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Re: a7 STAR tWIN CONRODS: "small" or "large" journals?
« Reply #11 on: 06.06. 2010 21:26 »
Ok Thanks Trev, that broadens my options to include post '54 rods (subject to the oil-hole considerations)...

And thanks Brian in Oz, I was watching those rods on eBay and bid on them, but was not succesful - I did notice a couple of small nicks in one of the rods which put me off a bit - but I understand if these are polished out the rods would have been okay.

I'll keep my eyes open for another secondhand set...