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Hi All - before “boxing up” the engine I noticed a “strange” stamping on the cylinder barrels. There’s a “B” on the outer surface of both and a * on the front of only one cylinder (LH - see photo). I thought these might have been identifying the pistons for correct clearance (they were originally rebored to +40 when I bought my box of bits) but there’s no corresponding marks on either piston.
Anyone got a idea what they’re for please?
Bruce
It's the grade of piston to…
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Thanks John - glad I’m not …
Thanks John - glad I’m not “missing” something on the rebuild then! As they’re the only barrels I’ve got out of 3 engines it was a bit of a mystery as nothing to compare to.
Bruce
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It's the grade of piston to be fitted when new at Norton. Production boring was not as accurate as the piston makers capabilities in that period so they bored and measured before selecting a piston to fit. A reborer is more accurate as they are all one offs so no need for graded oversized pistons.