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  1. #1

    Join Date
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    Rebuild lean siezure Disaster..

    Hi, guys.

    bad news... first calm day, after my rebuild, and i had a lean siezure. did a highspeed run and she cut out, managed to get back in to shore, got her home and did a compression check 150,80,150psi. center jug lost some piston crown by the exhaust port, but no cylinder scoring at all, outer two pistons show some signs of siesure, slight build up of aluminum on the edge of the crown. i don't understand how this happened. i run stock 38's dechoked and casting bosses removed, 110 mains high 1 whole turn out. stock is 107.5,95,107.5 for mains i believe( i have not got them to hand) and 7/8 turn out +/- 1/4. i have had these carbs apart 3 times for poor running, found some dirt in the low's, fitted new diaphragms, and check valves, and the 110's.

    i have a few questions.

    i have not stripped the motor right down, but as the compession is ok on the mag, and pto, and no cylinder scoring, could i leave these pistons in and just replace the center?

    do you think the fuel pump could cause this?

    before this happened it had a running problem. if you crused at half 3/4 throttle then came off the gas for a few seconds and then pulled her wide open she cut out. if you did the same and kept the throttle open very slighty then opened her full she ran ok. it's running standard low's and 1 turn out (within manufacturer specs) with standard needle valve and spring..



  2. #2
    Moderator DrewNJ's Avatar
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    air leak?

    I don't see any problems just replacing what needs to be replaced on the middle jug. But a lot will have to do with what the other 2 look like overall... If 1 & 3 show signs of seizing then it will be more prone/easier to seizing in the future.

  3. #3
    philip_gpr's Avatar
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    post up pictures of both the piston tops and a picture showing the inside of the bottom of the pistons (this probably will show if lean and how lean)



    "pulled her wide open she cut out."

    this sounds like a symptom of being lean

    lean the motor cuts out

    rich the motor stumbles


    if it is lean then it could be the jetting or a faulty fuel pump - the pictures will help solve this by showing if all 3 cylinders were lean or just 1
    Last edited by philip_gpr; 04-27-2008 at 08:41 AM.

  4. #4
    cheatin' piston popper addicted's Avatar
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    Quote Originally Posted by akatitan View Post
    i run stock 38's dechoked and casting bosses removed,

    meaning that big ass block of aluminum down the side? if so, that will drasticly alter your jetting. the way the incoming air plays on that and the fuel passages affects how the fuel is pulled out of the carbs.

  5. #5

    Join Date
    Feb 2008
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    Ashford,Kent,UK
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    addicted,
    i removed big ass block of aluminum down the side as you put it, on my 700 raider with no ill effects. i am not saying that this may not be the problem it may be apples to oranges, but i am just trying to be subjective. anyway here is some pics.
    i added the pto, just to show how much oil this engine has ! is this normal?
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  6. #6
    Wow lean across the board!

  7. #7

    Join Date
    Feb 2008
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    Quote Originally Posted by ZMANN View Post
    Wow lean across the board!
    thanks,
    yes i think we have established it is lean, i am trying to find out why.

    Zmann, what is the advantage of copper gaskets i see you have some for the 1100..
    Last edited by akatitan; 04-27-2008 at 02:37 PM.

  8. #8
    copper gasket ? not me! I don't sell, what grade of fuel do you get where u live? Z Edit ! I see were u would think I sell parts! that is Zigler's site I will clarify my sig thanks
    Last edited by ZMANN; 04-27-2008 at 03:14 PM.

  9. #9

    Join Date
    Feb 2008
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    Ashford,Kent,UK
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    i run yamlube 50:1 premix, and 95 RON, i think it is the same as the U.S 92..

  10. #10
    Thanks for the conversion the ron always gets me! I run 91 and 40 to 1 in all my rides ! I guess you need to rethink your jetting! you have a high compression head and some breathing mods the guys on here dialed my jetting in on my 1200's

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