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  1. #1
    Water Bum Rodneyae's Avatar
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    Differences Between 780 and 650/750 jugs

    Ok, I am looking at doing something different. So I need to know what the differences are beetween the heads. I tried to do a search on it and came up empty handed. I rember something about not being able to use the 780 on a 650/750 case. But I would like more info. Also a compatibility thread might be helpfull for future referance.

    Thanks,
    Rodney


  2. #2
    ph2ocraft's Avatar
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    The difference is in the exhaust manifold pattern. If you wanted to install the 780 cylinders look for an exhaust manifold as well.

  3. #3
    Thats a good question! besides what Pho said what is the difference between the 750 and 780? besides the flipped manifold mounting holes? I glanced at the specs and both jugs seem like they have the same bore? I know the case is relieved for a 780 is it just the rods?Z

  4. #4

  5. #5
    Cool! Thanks dart I guess I miss read at one time! so the crank is the same but why is the case modified on the 780? or am I still off base?
    Z

  6. #6

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    Cool

    if you update to 780 topend make sure to use 780 head gaskets or you'll have over heating problems

    later cd

  7. #7
    Hayabusa's Avatar
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    Quote Originally Posted by ZMANN View Post
    Cool! Thanks dart I guess I miss read at one time! so the crank is the same but why is the case modified on the 780? or am I still off base?
    Z
    The upper case on a 780 are "factory ported" for performance. It's worth a few extra ponies over the unported 650-750 cases.

  8. #8
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    First, the 780 top case has 2 large channels plowed out for more fuel. The pistons have interesting voids in the sides above the pin. The cylinders have 2 more ports on the exhaust. As previously stated, the exhaust manifold is different. And a different CDI that has more agressive timing and possibly a higher rev limit? (not sure on that rev limiter)
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