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  1. #1 Carb question regarding cams 
    C-Moto Senior arancara's Avatar
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    Typically as airflow improves you rejet up, but does that also apply to longer lift cams? Yes I've tried google without any success, the way I see it air gets mixed with fuel as it passes through carb, since the duration increases of the lift so does the exposure of air going through the carb, so I'm not sure if jetting is required for cams.
    Lexmoto XTR-S 156FMI (156cc big bore) - 163FML Cams (+1mm lift) - Foam Filter - Sports Exhaust - 17T Sprocket - 110 Main Jet - PZ30 Carb - Aprillia RS Ignition Coil - Casoli CDI

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  2. #2 Re: Carb question regarding cams 
    Senior C-Moto Guru Zorge's Avatar
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    And a little experimenting is not an option for you?

    Тampering with jets is inexpensive hobby, isn't it?
    Ask me nothing - I DO NOT speak english. Really...
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  3. #3 Re: Carb question regarding cams 
    C-Moto Senior arancara's Avatar
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    I have jets of different sizes, but need to know if I require more sizes if cams do require more jetting for when the cams arrive. As I imagine on a injection engine the duration of the injection would be increased with a longer lift cam, but since carbs are just air passing through and getting exposed to petrol I am not sure if jetting is needed or not.
    Lexmoto XTR-S 156FMI (156cc big bore) - 163FML Cams (+1mm lift) - Foam Filter - Sports Exhaust - 17T Sprocket - 110 Main Jet - PZ30 Carb - Aprillia RS Ignition Coil - Casoli CDI

    My Project: http://xtrsproject.wordpress.com/
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  4. #4 Re: Carb question regarding cams 
    Senior C-Moto Guru Zorge's Avatar
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    Let's not bother ourselves with theory in vain because only God knows what look like lobes of that new camshaft, and thus the timing and duration. I would have thought of jetting only after installing the camshaft.
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  5. #5 Re: Carb question regarding cams 
    C-Moto Senior arancara's Avatar
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    I'm asking if more aggressive or longer lift camshafts in general need jetting.

    If yes I'll order a few sizes up so once the cam arrives I can install accordingly and do it all in a few days rather than installing cams, only to find out it does require jetting, ordering and then waiting a week for jets.

    Also Humanbeing if your around any chance of finding me another seller of the CB150 longer lift cams, I placed an order through an agent and sadly its been two weeks without the seller responding at all so I need to find another seller of cams for the OHC variant.
    Lexmoto XTR-S 156FMI (156cc big bore) - 163FML Cams (+1mm lift) - Foam Filter - Sports Exhaust - 17T Sprocket - 110 Main Jet - PZ30 Carb - Aprillia RS Ignition Coil - Casoli CDI

    My Project: http://xtrsproject.wordpress.com/
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  6. #6 Re: Carb question regarding cams 
    Senior C-Moto Guru MJH's Avatar
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    I think you will have a stumbling engine at idle, that will smooth out at high rpm.
    Performance cams have wider lower lobes and increase the cycle overlap in the valve timing.
    It will increase the rpm the whole process happening faster, it may not require more fuel as the size of the chamber is constant the air and fuel is optimized separately. I would say, my concern would be more that of timing of the firing and it matching the new cam. That being does the stock CDI work with the new cam? I wonder if it could fall short in its ability to charge and discharge fast enough? It may have a limit?
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