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So, if you take a motor with a wilder cam, higher CR ( i.e. 38mm), more piston area (i.e. 904), and good chamber design, would the result be no change to the advance?



As long as the +'s equalled the -'s that would be correct, but it doesn't tend to work out like that.

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Why does the 790 look incomplete? Should I re-map (if thats possible) if I go big bore, keeping stock 790 cams?



The 790 50%, 75% & 100% maps start off with higher advance at low revs, that's why it looks incomplete. It's beneficial to remap when engine changes are made, but you'd expect me to say that. Not remapping certainly won't hurt your engine, it's your choice.

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If I understand this correctly and assuming that each colour range represents around 1 Degree of advance with initial advance set at 4 to 6 degrees BTDC, the 790 at 100% TPS load has about 3 degrees of less advance at max rpms that the 865? I thought the throttle maps for the 790s were a bit more radical and they make their power at higher rpms.



The maps were created using the automatic "scale to page size" so each map is a slightly different scale to the other.

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Higher rpm usually mean more advance?????



Except at wider throttle openings where the engine is more efficient, so less advance is needed.

Mike (UK) _____________ 2008 Bonnie Black Special 2010 Speedmaster https://www.triumphtwinpower.com