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  1. #1

    Grenaded 787 RFI

    Just picked up a 2000 GSX RFI that had a brand new topend put in it. Not 5 minutes into the first ride the crank locked up. Pistons look like they just came out of the box (one has some dings in the dome), cylinders still crosshatched but it wont turn over. Upon further dissasembly I found some debris had passed through the rotax blade (unsure if that is the correct terminology) and grooved the cases pretty good along with bending the rotary blade pretty good and breaking up the intake port on the edge. Pretty sure it was some crank parts, probably lower rod bearings. I was originally going to just buy a new crank, one piston and any rotary shaft parts needed but am now thinking it is just easier and more cost effective to buy a complete SBT motor. Is this correct?


  2. #2
    KrunchovXPL-GTX-RX's Avatar
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    I am not a personal fan of those guys, but I have heard that their 787s are pretty decent.

    In your situation, with so much case damage to deal with, this may well be the best solution.

  3. #3
    Quote Originally Posted by KrunchovXPL-GTX-RX View Post
    I am not a personal fan of those guys, but I have heard that their 787s are pretty decent.

    In your situation, with so much case damage to deal with, this may well be the best solution.
    Yeah I have heard good and bad on SBT but the price is right. And it could save me a bunch of work.

  4. #4
    Quote Originally Posted by Yamanube View Post
    Yeah I have heard good and bad on SBT but the price is right. And it could save me a bunch of work.
    This may prove to be costly if you actually have case damage ...

    If you have a busted intake manifold thats one thing but if the mating surface between the case and manifold is busted up that can get expensive

  5. #5
    Quote Originally Posted by radeon View Post
    This may prove to be costly if you actually have case damage ...

    If you have a busted intake manifold thats one thing but if the mating surface between the case and manifold is busted up that can get expensive
    Yeah, I was told they will hit me for a core charge most likely. So I guess I would be better off finding a good set of used cases? Are they hard to find and what is a fair value for them?

  6. #6
    TX21's Avatar
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    I did two 787's one from SBT (my first one) and then did the second motor myself. Its easy as hell and cheaper to do it yourself. Sounds like the prev. owner tossed two pistons in a messed up motor and didnt clean/inspect the crankcase or crank.

  7. #7
    mibunkerking's Avatar
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    i had basically the same thing happen to me, except the top end needle bearing gave out and the needles fell into the crank. sheared the rotary gear, destoryed the rotary vavle and mating surfaces. i paid a machinist $94 to resurface the RV surface while maintaining the gap clearence. replaced the seals, RV gear, RV degree plate, new top end. in all i think it was like $400. but i was able to save the crank. if the crank is toast then SBT is the way to go

  8. #8
    Well the grooves in the rotary valve surface are about twice as deep as the valve is thick along with some very nice damage to the edge of the intake runner right at the valve, I can't imagine they can be repaired without welding. I found a nice set of used cases for $200, may just go that route with an SBT crank and one new piston.

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