Hi all, I have recently managed to get my 650 Dommie back on the road after a dalliance with an offset crankshaft which turned out to be a monumental disappointment, but I digress.
The bike starts and runs pretty well up until about half throttle or so, then it starts to splutter and will not rev any more. I cannot get it to rev any more than 3500.
I bought the carbs new from Amal (930s). They came with 106 needle jets and 280 mains. I have had them apart and cleaned them, raised the needle position to the highest and made sure the choke slides are not interfering. The float levels are also within spec.
The ignition system is a Tri Spark setup, I have checked the ignition timing with a light and it has full advance of around 28 to 30
My question is, are those jet sizes right for the 650 motor? Any help here would be greatly appreciated.
Stewart Denton-Giles
Your main jets appear to b…
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Your main jets appear to be far too large for twin carburettors. Re-jet with 220 mains and take it from there. See attachment for other settings.
Attachments norton-carbs-1959-1965-doc