Re: Geoff Duke--349cc
No Ian -- wasn't an error.
If you look at the programme, Geoff was entered originally by Reg Dearden on a 348 Norton - bore and stroke 76mm x 76.7mm, 348.1cc. Standard production Manx dimensions of the time.
Towards the end of practice week, however, Norton's offered them an experimental engine. This was a very short-stroke motor, 80mm x 69.5mm, equal to 349.45cc. Bill Lacey had worked on this engine, which had a one-piece crank, plain bearing big end, and coil valve springs.
Before they had a chance to try it properly, however, Norton's took it back and gave them a 1954 works 350 engine to use -- 78mm x 73mm, 348.96cc, so you could I suppose call it 349!!
After all that, the bloody thing wouldn't rev over 6000 on race day, and finally expired at Sulby on lap one!!
Incidentally, and still looking at the programme, Bob Mac was entered by Joe Potts on another 78 bore/73mm stroke 350 Norton, so Joe had obviously blagged a 1954 factory 350 himself!
The calculation hadn't been done in this case, however, and the programme calls it a "348 Norton Single Cylinder 78 x 73"!
Just goes to show, there ain't no such thing as standard Manx Norton dimensions!!
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