RichG wrote:
Your bikes seem to have had less than 5000 miles on each bottom end John, so if that was me, I'd have probably left them as is, unless there was some issue like starting due to lack of crankcase compression.

Those miles are what I did on them;
the 'Castrol '28 had 24000k's on the clock before the 030 card was added (and that was by the owner before last).
The Rothmans engine was apparently "Barrys old motor" according to Leigh.
The '18 is a total unknown, it's a '21 motor for starters.
The '21, well apart from coming without a speedo cable........

You are right in theory of course and all other things being equal a new crank is the way to go. But this is the real world, time, money and patience aren't in infinite supply.
Maybe I've been lucky, maybe both cranks will let go at the next race, maybe both bikes will run for another five seasons without issue. Whichever, I won't be ripping the bottom end apart until I'm pretty sure it's the cause of problems unless I've got the money to spend having it trued, the cases done etc.
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