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Discussion Starter · #1 ·
Hi I'm looking for advice about conrods.

My '71 Daytona has had piston rings break up in one cylinder and the previous owner replaced the piston but the rod is lightly peppered with pits and has one deep gouge out of it so I think it is likely to snap at some point if not replaced.

Question 1
I have seen billet rods (much to expensive for me) and they are advertised as being suitable for T25/B25 singles as well. Does this mean that late tri/bsa singles used the same conrod as late unit 500s?

The reason I ask is because I have seen a mint condition late B25 rod (plain small end eye same as my Daytona) for sale an I'm wondering if it would be a suitable replacement.

Question 2
Could I replace my late (unbushed) rods with the earlier bushed type? Are the big end journals are the same diameter etc.

Question 3
Does anyone know where I can get NOS unit 500 conrods?

Cheers, and happy easter to all.
 

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The 250cc single engines are under square long stroke ,67x70mm vs 69x65.5mm c series unit triumphs,the same as trident /rocket3 so would be necessary to do some rod length/journal size comparisons to answer that question.Triumph were going to change the Daytona dimensions to the 67x 70 but production ceased before changes were made.The 67x70 dimensions work very well in four strokes similar to the 54x54 (and other dead square dimensions)in two strokes
Bushed and unbushed rods are compatible and may be slightly different weight so poss. may effect the engine balancing a little.
Second hand rods turn up from time to time ,though rods got made beefier over the years ,and one can be resized and weight matched to old rod relatively cheaply if it needs it which may be better option than fitting an odd chinese replacement
 
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