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Lean or fat?

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I looked in the forums but I do not understand this fact: if the motorbike (4 strokes) with the accelerator to the max or near the max loses some hits to top revs, when is still building revs, in a discontinuous manner, is main jet lean or fat?

I prefix that: the limiter was removed; the over revs should reveal itself more hardly; changing the needle clip position is irrelevant; the main jet is 168, the carb is a FCR41, the motorbike a VOR400 with worked head; the distribution and the valves just revised by a specialized vor mechanic; the jd jetting kit ( JDK001 ) just ordered but not arrived yet.

Thank you to all.

Paolo

:)

I hope you understand my exposition, it's hard to explain the thing in italian ( I'm italian... ), imagine in english...

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Your bike can sputter or cut out from being too lean or too rich. It would be very useful to get a spark plug reading. That should tell you in a very obvious way. If the plug is black, too rich. If the plug is white, and the bike seems hotter than Phoenix in July (American expression) you are too lean.

Are you jetted the way your owners manual tells you to start out as a baseline?

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did you say if you removed the rev-limiter you can get more top end?

most 4 strokes will float the valves around the time of rev-limiter so if you do that you are only hurting the motor more.

most bikes drop off in power before the rev limiter kicks in.

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Is this a 2005 VOR 400?

If this is a stock '05 VOR 400 with FCR carburetor, use-

#42 pilot jet

Blue marked needle, #3 (3rd from top clip position)

#172 main jet.

If this is a replacement FCR carburetor with older type pilot jets-

#48 pilot jet

Blue marked needle, #4 (middle clip position)

#172 main jet

Thanks,

James

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Thanks James, the vor is a 2001 model with older 41 FCR type.

Binder, the limiter was removed by a previous owner.

I'll try the settings suggested...

Thanks to all

Paolo

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