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  1. #1

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    Gutting gpr waterbox (100 rpm)

    Ha Ha Ha!!!!just kidding about the 100 rpm but! Has anyone ever tried doing this?I know there has been a recent thread on the 4 stroke section about gutting out the waterbox. There are some possitive results on the 4 strokes so what about the 2 strokes?
    if i had an extra box i would try it and see!!! i was thinking of gutting it out but yet leaving the sound supression in.I cant see what it would hurt may not do anything at all except make it a lil louder. whats everyones thoughts on this?


  2. #2
    OLD # 7 IEGPR's Avatar
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    Well the first thing that come to mind is your going to reduce back pressure. this is a good thing for 4 stro but BAAAAD for 2 stro

  3. #3
    THE PLATE MAN JIM'S PERFORMANCE's Avatar
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    bad idea to gut water box on a 2 stroke you will lose a lot of rpm's, 2 strokes need back pressure.

  4. #4
    Quote Originally Posted by JIM'S PERFORMANCE View Post
    bad idea to gut water box on a 2 stroke you will lose a lot of rpm's, 2 strokes need back pressure.
    +1

    1200 water box with a riva blue tube is the ticket for a big bore single pipe.

  5. #5
    Gutted box on a GPR with tripples requires 26mm stingers (32 is FPP standard) to get the right back pressure. This is for 1200cc all out race motor on MS109

  6. #6
    YudLuz2's Avatar
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    Quote Originally Posted by rossnemo View Post
    +1

    1200 water box with a riva blue tube is the ticket for a big bore single pipe.


    +1

  7. #7
    Moderator RX951's Avatar
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    Backpressure is important for a two stroke.

  8. #8
    What backpressure would be required on a 1460 running tripples??
    Anyone?? Stingers between 32mm and 26mm or just 32mm??? Is anyone running a factory waterbox with a 1460?

  9. #9
    Quote Originally Posted by bigrob View Post
    What backpressure would be required on a 1460 running tripples??
    Anyone?? Stingers between 32mm and 26mm or just 32mm??? Is anyone running a factory waterbox with a 1460?
    Depends on your timing at 7400-8000 rpm and your compression/fuel. Some tripple pipes ran 36mm stingers on GPR's.

  10. #10
    Pistonwash's Avatar
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