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Yamaha S200TXRV problem. Rodbolt, need your help!!!

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  • Yamaha S200TXRV problem. Rodbolt, need your help!!!

    I have been chasing a surging issue at idle for a year now. The engine runs great at WOT. it sometimes runs fine at idle and then sometimes doesn't, it will surge. Things I have done

    Compression test - everything fine @ 120 psi.
    Rebuilt carbs
    Link and sync
    Adjust low speed jets to spec
    Tested coils - there was some corrosion were the coils grounded/bolted to the CDI assembly so I wire brushed it off and still no difference.
    Tested spark on port side and noticed there was very little to no spark on all three cylinders. When I say weak, I mean I had the spark gap on the tester almost touching and it was barely arching.
    Tested spark on starboard side and spark was great. When I say great I mean gap of an inch would get good spark.

    After the spark test it led me to believe this was the cause of the surging.
    What I need help with is the next step. Should I test - CDI (is there a way to test?), stator, or is there a switch that kills those three cylinders when shifting in and out of gear? Any help would be highly appreciated.

    Update - I pulled all of the spark plug caps off and tested them. Each had from 4.75 - 5.25 kOHMs except 1. It had 368 kOHMs. Could this bad cap be causing my idle surge?