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  1. #1

    Looking for more power on my 1990 waverunner 3

    I have a 1990 WRA 650 Waverunner 3 that i absolutely love. As slow as it is, its just so much fun and it just always works. I was thinking about trying to get some more power out of it but hopefully not lose reliability. right now its completely stock but i was thinking about possibly putting a pipe on it, throwing 2nd carb on there (its got a single 44 i believe), a nice SS impeller and maybe quick turn plate. If done right, can something with mods like that be built to be reliable? Can it also be something that can have pretty decent holeshot?

    What pipes would you recommend? what pipe impeller do you suggest and is a 2nd carb worth it? I got the ski for free 5 yrs ago and ive ridden the snot out of it for the last 2.5 and it hasnt complained one bit, is it worth starting to mod it anyway?

    Thanks for all your advice!

  2. #2

    Join Date
    Jan 2006
    Texas City, Texas
    Rethink your approach to more horsepower. Some of the stock Yamaha pipes are not really the problem. In fact, a lot of them are well designed (for instance the GP1200 and GP1200R exhaust pipes). It may alos be true for your boat.

    If it were my boat, I would contact Harry and Gerhardt at Group K using this web address:

    They specialize in getting the most out of an old school two stroke. You may find that you will invest in porting and increased compression rather than buying another carb and pipe.

    Also, consider converting your 650 to a 701cc motor. There are plenty of 701 pistons and cylinders laying around for sale for cheap. There is no replacement for displacement.

    If you communicate this idea to Group K, they will know wether or not the electronics would be compatible. If it were true, then it is a matter of just swapping the pistons, cylinder, head, and rejetting your carb. For sure they will put you in the right direction for the best power increase with the best reliability and the best price.

  3. #3
    vomitspot's Avatar
    Join Date
    Apr 2006
    mobile alabama
    stick with the single carb
    get ya some aftermarket reeds
    maybe raise the compression
    if you can find a pipe buy it wr3 perf parts are gonna be hard to find !
    good ss impeller is always a +
    if its in your budget upgrade to a 701
    the 650 ex port is the size of a quarter but thats what makes it super reliable!

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