Hello Norton Enthusiasts
I hope someone can help. I am completing the rebuild of a Norton 500T engine 1947. The maintenance manual says ignition timing 5/8" BTDC. The internet varies and some say 38 degrees and others 42 degrees BTDC. Which is correct?
Secondly the timing marks on the gears, are these likely to be correct for this year. I have read that these can be very inaccurate. the engine is very similar to the ES2 (alloy barrel difference).
Thanks for reading my request.
Fran
Read page 134 of the singles…
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Re ignition timing - page…
Re ignition timing - page 169 has info. Note that with these long stroke engines, measuring 5/8" gives good accuracy. It's what E.F.Franks wrote.
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If you're running a flat top…
If you're running a flat top piston it will probably have a compression ratio of about 7:1 which will need 5/8" advance, any higher ( say 8:1 ), it will need bringing back to about 1/2", you might need to experiment to get it right.
John
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Read page 134 of the singles compendium on the technical section of the website. Should answer a lot of your querys