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  1. #1

    Join Date
    Apr 2011
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    australia
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    96

    Gas valves and what is so special about them ?

    Ok what is so good about the gas valves,how do they work and why do people change from electronic valves to gas ones ?
    also where is the best place to get a set and how much are they worth ?


  2. #2

    Join Date
    Jan 2006
    Location
    Texas City, Texas
    Posts
    1,249
    +1
    15
    They are simpler with less parts to operate than the mechanical valves. They are tuned independently.

    The gas valves operate on gas pressure from the cylinders and they literally "pop open" when your rpms reach between about 4600 - 4900 rpms. Because of how they suddenly pop open, it feels as if your engine has gone into another gear..... it feels great. The mechanical valves have a smooth transition when they open.

    On the 1200 models, the stock cdi will ramp the rpms down when ever you hit the rev limiter and the mechanical valves will close on a temporary basis. It gives that brakes on feeling when you ride in rough water. With the gas valves (or an aftermarket CDI) this feature is no longer there.

    They have a huge shoulder on the shaft, so if the valve were to break (it is very rare, but on occasion they do) the shoulder will prevent the valve from falling and hitting your piston and grenadeing your engine. When this happens, you will loose 2-300 rpm. At this point, you just replace the one valve.

    There is a lean spot in the mid to upper 4000 rpm range when you use the stock Mikunis which makes the engine prone to detonation at that point. The mechanical valvess slowly transition you through that spot. If you stay in that range to long, you can hurt your engine. The gas valves basicly jump over the lean spot, so your chances of detonation are reduced.

    You do not gain any rpms over the stocker valves. Because of the ease of operability, cleaning, and safety features, I chose to get some and would not go back. They are expensive for no added performance gains though.

  3. #3

    Join Date
    Apr 2011
    Location
    australia
    Posts
    96
    good information thankyou i will be running carbon fibre reeds a riva cdi novi 48 carbs riva heads and a set of tripple pipes so it sounds like its worth buying them tho how much are they ive seen people buying them for around $600 is this correct or a bit more for brand new ones ?

  4. #4

    Join Date
    Aug 2009
    Location
    LI, NY
    Posts
    344
    +1
    3
    Quote Originally Posted by ryancoggo View Post
    good information thankyou i will be running carbon fibre reeds a riva cdi novi 48 carbs riva heads and a set of tripple pipes so it sounds like its worth buying them tho how much are they ive seen people buying them for around $600 is this correct or a bit more for brand new ones ?
    Check out Art at Jetworks on his blackjack carbs. Cool project.

  5. #5
    Riva quit makin em good luck finding them if u do let us no where.

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