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  1. #1

    Problem surging and loud noise from reed valve filters....

    Second run since reinstalling the head, and multiple minor upgrades to exhaust intake etc. Today when getting back to the dock the engine started surging about 800-1500 like a continous wave. It sometimes stalls. It's also got a new loud echo/hissing from the filter I installed at the two reed valve plates that are on top of the valve cover. I don't know what they do, but they seem to be ported to the exhaust valves. I think one of them is stuck open.

    Engine runs great besides a constant miss under load at 3,000 rpm but clears up at WOT. I'm getting 55 mph and great throttle response too. While crusing at 3,000 rpm (10 mph) you can clearly hear one cylinder dropping in and out like it's loading up. Maybe I have the valve clearances out of wack after reinstalling the head... I've had that problem before, runs great cold but hot it drops a cylinder.

    Besides the obvious changing the plugs, is there something else common with this 1200F engine???? BTW it's a 2005 STX 12F with 43 hours on it.


  2. #2
    nicjak's Avatar
    Join Date
    Mar 2008
    Warragul, Downunder
    just block the valves off with a block off plate, they are not needed and yes they are open direct to the exhaust ports.

  3. #3
    Thanks, I just also looked at teh R&D kit. I can probably do it myself right? It makes sense, they may be causing surging if stuck open. Also may be why my top speed is less than last year.

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