1970 Cl350 stutters between 2850 rpm & 3000rpm
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  1. #1
    Junior Member Quackowski's Avatar
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    1970 Cl350 stutters between 2850 rpm & 3000rpm

    After finally getting my "Crimson Cadaver" up and running, I'm finding it has a slight hesitation, or a stutter beginning at around 2850 rpm. Once the rpm's are past 3K, the bike runs fine again.This scenario plays out in all gears. Some backround info on the bike: the mileage is 22K, it sat for 12-14 yrs. before I bought it. I changed the oil & cleaned out the oil filter cup, replaced the points, plugs, rebuilt the carbs, cleaned out the gas tank, rebuilt the petcock, new fuel lines, adjusted the valves & cam chain tensioner, and set the timing. I did not remove the mounting plate for the points and I'm wondering if the problem is caused by a malfunctioning spark advance mechanism. Any thoughts or theories?1970 Cl350 stutters between 2850 rpm & 3000rpm-dscf0001-22-.jpg

  2. #2
    Senior Member mike in idaho's Avatar
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    Most likely it's that open exhaust pipe causing it. It isn't uncommon, when switching to open exhaust, to have the engine stutter or miss in a particular rpm range. There is a common misconception that these motors need back pressure in the exhaust system to run right. More correctly, the exhaust pressure pulses need to dampened in such a way to keep exhaust reversion pulses from upsetting the carburation. Google exhaust reversion, some interesting reading there.
    Last edited by mike in idaho; 08-10-2019 at 10:16 AM.
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  3. #3
    Senior Member singletooth's Avatar
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    I'd be happy to buy that open exhaust pipe from him. More than happy. Welcome to the board.
    Living It Up On The Down Side

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  5. #4
    Senior Member Kerosene's Avatar
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    Got a timing light to verify the advancer is working properly? Carbs 100% clean?
    74 CB350F
    72 CL350

  6. #5
    Junior Member Quackowski's Avatar
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    Quote Originally Posted by Kerosene View Post
    Got a timing light to verify the advancer is working properly? Carbs 100% clean?
    I'm in the process of borrowing a timing light to check and hopefully eliminate the spark advance mechanism. The carbs are Felix Unger clean.

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