square 4 conrods

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william shortall
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square 4 conrods

Postby william shortall » Wed Oct 10, 2018 1:47 pm

I have been advised to replace the conrods on the bike when it gets stripped down
Is this the only way forward as funds are low , but will do anything that is required

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paul.jameson
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Re: square 4 conrods

Postby paul.jameson » Wed Oct 10, 2018 9:32 pm

Replacing the con-rods is no bad idea, if you have the funds. Cleaning out the sludge traps is absolutely essential and costs next to nothing. With clean sludge traps the risk of breaking rods is low. With blocked sludge traps - as most are - the risk of breaking rods is about 100%.
Paul Jameson
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
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MARK.WALSH
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Re: square 4 conrods

Postby MARK.WALSH » Wed Oct 10, 2018 10:22 pm

they are dear to replace, but when done will give you peace of mind with one less thing (or should I say four) to go wrong once you have finished your rebuild.
If you cant afford them look carefully at your existing rods for any defects, knocks etc where weak spots can get worse due to age.
As Paul says - the sludge traps are a must.
Good luck on the restoration - these bikes are great fun to ride once completed

nevhunter
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Re: square 4 conrods

Postby nevhunter » Wed Oct 10, 2018 11:40 pm

The speedway JAP's that have alloy rods usually only ran them for one season and then put a hacksaw cut in them and hung them on the wall. The alloy fatigues and that isn't easy to test for. it's probably a question of miles and at what RPM's. New billet CNC'd ones would be good insurance and the sludge traps are a must to clean. (unless you are absolutely certain they were done when the motor was and it hasn't been used and then sat for a while). it's not worth risking and the evidence of the rear rod LH not getting oil due blockage is all there. Twins are no different. Any motor with a horizontal oil gallery in the crank is the same. It acts as a centrifugal separator. Nev


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