Thursday, December 2, 2010

900SS With FCR 39 and 41 Carbs

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Two 900SS, both fitted with slip on mufflers (Staintune, Gia.Co.Moto), std airbox lids without snorkles and std jetting. Before they were pretty similar:
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After, FCR41 in red, FCR39 in green. Both runs done with the same 152 main jets.
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With FCR39 before and after
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With FCR41 before and after
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2 comments:

bigiain said...

How much of the difference do you suppose is due to the A/F ratio differences? The blue trace is generally closer to stoichiometric...

Brad The Bike Boy said...

I'd say on average the blue lean is as much too lean as the green line is too rich. But I doubt there'd be more power in either of them. These two runs were actually done with the same main jets (152). I tried in the 39's and then removed them and fitted 150 to it. I fitted them to the 41's to give a direct comparison, no idea why there's so much variation though.