Author Topic: wanted: Small journal con rods for 1955 A10 swinging arm model  (Read 671 times)

Offline Guy Wilson

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I'm looking for one, ideally a pair of con rods for my 1955 A10 Small journal crank.
Guy
Kenya
(i have a UK postal address as well)

Offline Rocket Racer

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  • A kiwi with a racing A10 rig and too many projects
    • NZ Classic Sidecar Racing
http://shop.srmclassicbikes.com/srm-a10-small-journal-high-strength-billet-conrod-each

How did you get on with your rod search? The problem with all second hand rods is we typically don't know their lineage and having them crack tested, straightened, radiused, rebushed, shot peined and then fitted fresh bolts often makes reuse of old ones uneconomic.

If you want to go down the path of 2nd hand, I think I have some... you can always PM me.

A good mate fitted some SRM onesto his 55 plunger flash and while expensive he is very happy with.
Tim
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand

Offline Guy Wilson

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Thanks Tim,
I'd sort of come to the same conclusion about the economics of fitting second hand rods. What's stopped me at the moment is the economics of the whole thing..I'd looked at the SRM replacements but I can't justify the price for the amount of riding I do on the BSA for now... I have a decent large journal crank from a spare engine that I'm going fit in the original cases and rebuild using the pistons and barrels from the spare engine. The original small journal pistons were flat topped, the large journal are domed, so I wanted to maintain the crank balance as much as possible. All this is set of the new year now. Work has been crap here for a year because of all the security concerns and I've had my eye inevitably on other things...
More when I get back into the swing of things,
Guy

Offline Rocket Racer

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Guy,
if you have a set of rods that are showing nice even wear on the big ends, a clean of the sludge trap and a fresh set of shells might be the way to go (with the LJ crank) to keep expenses down. Do put the rods on something flat and check their straight though.

re pistons, (IMHO) the catch with balance is that successive over sizes take the balance factor the wrong way (as the OS pistons are typically heavier -thicker walled), whereas for modern (faster) traffic the norm is to take the balance factors the opposite way. So with the piston choice of flat vs domed, consider the weight and run the lighter pistons.
You mention domed and there are a number of domed options commonly varying from 8.25 to 10.5:1 - for a road engine a lower compression motor is typically less harsh/more pleasant and in the scheme of things just as quick anywhere other than the drag strip. So I wouldn't be rushing to fit the domed pistons that came with the crank, there's also nothing to guarantee the motor was balanced for those pistons  *dunno*   . The pistons that taper to a raised flat crown are a nice compression option usually in the 8.25-8.5:1 range. The ones with a rounded dimple 9:1 need higher octane fuels and the ones that look like they might come out of a triumph 10.5 or 14:1 -avoid the first unless on 100 octane and the second unless racing on methanol  *eek*

Hope the work comes right for you.
Tim
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand

Offline Guy Wilson

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I'll stick a photo of the domed pistons on the site after the holidays. The original SJ flat topped pistons were very gentle and an easy ride . My triumph is a pig and has higher compression pistons, so its worth looking at I agree.
Many thanks
Guy