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  1. #1
    Nizu^'s Avatar
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    2004 Gp1300r Cracking exhaust bolts

    HI, Sorry my bad English.. I have struggled with this matter whole summer now, I tried find same kind of problem from forum without result... My Gp is cracking exhaust bolts all the time. Bolts has now cracked 4 times and every time from end of the pipe. One time bolt cracked in cylinder head(rear bolt keeping exhaust stay to cylinder head), twice bolt has cracked in exhaust(rear bolt which is attached to stay which is back of the cylinder head) and now front bolt which keeps exhaust stay benead exhaust pipe attached to motor. Last time I changed all the bolts new ones(original Yamaha) and tightened all the bolts to 40NM which is recomended by Yamaha and still front bolt of the exhaust stay benead pipe has cracked. Does someone has any suggestions what is problem with my ski?? Motor works fine and compression is ok. Ski has 450Hours now...Thanks!
    Last edited by Nizu^; 08-15-2013 at 03:21 PM.


  2. #2
    Almost's Avatar
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    Did you use loctite when you put the bolts back? You might want to check out all the other bolts and motor mounts. Somthing has to be loose for you so keep breaking the same bolts.

  3. #3
    mudslanger's Avatar
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    It could be the order you are tightening them down. you should loosely snug all bolts down so nothing is binding. if you are tightening the lower bolts first then the exhaust to head next and the nut pulls the pipe over and then the lower rear bolts pull the pipe down all the bolts would be binding and could cause them to break.

    you should be able to run all the bolts in by hand and if you have to use a wrench make sure all the exhaust bolts are run down all the way and NOT tight until every bolt has been run in. then torque then to speck. that way nothing is in a bind.

  4. #4

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    Have you lost an intermediate shaft lately?

  5. #5
    Nizu^'s Avatar
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    Quote Originally Posted by Almost View Post
    Did you use loctite when you put the bolts back? You might want to check out all the other bolts and motor mounts. Somthing has to be loose for you so keep breaking the same bolts.
    Yes, I used Loctite 2701, the 271 which is recommended by Yamaha is not available in Finland. 2701 is little bit harder stuff...I will also check out the motor mounts when I will take the exhaust off and start to drill cracked bolt out from the motor exhaust stay...

    Quote Originally Posted by mudslanger View Post
    It could be the order you are tightening them down. you should loosely snug all bolts down so nothing is binding. if you are tightening the lower bolts first then the exhaust to head next and the nut pulls the pipe over and then the lower rear bolts pull the pipe down all the bolts would be binding and could cause them to break.

    you should be able to run all the bolts in by hand and if you have to use a wrench make sure all the exhaust bolts are run down all the way and NOT tight until every bolt has been run in. then torque then to speck. that way nothing is in a bind.
    I did this wrong last time and that can be the reason, I did it this way
    1. attached stay benead pipe to the pipe and put bolts in 40Nm
    2. after that pipe to itīs place
    3. Put two bolts which attach benead pipe stay to the motor and put them in 40Nm
    4. put two exhaust stays to cylinder head in 40Nm
    5. put the back bolt in

    Next time I will make sure that nothing is binding



    Quote Originally Posted by salty View Post
    Have you lost an intermediate shaft lately?
    I do not know about this I bought ski last winter and it was just rebuild then. Can intermediate shaft problem cause exhaust bolts to crack??

    When ski is idling it makes sound like prob is loose, the sound stops when rpmīs will get higher.
    I do not know if there is some loose that let also the motor move more which could also cause exhaust bolts cracking...

  6. #6

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    [QUOTE=Nizu^;2241385. Can intermediate shaft problem cause exhaust bolts to crack??

    When ski is idling it makes sound like prob is loose, the sound stops when rpmīs will get higher.

    I do not know if there is some loose that let also the motor move more which could also cause exhaust bolts cracking...[/QUOTE]

    No. In this case, a bad shaft is just a symptom of another problem namely a poor alignment. Poor alignments can cause high vibrations which can crack points where the exhaust bolts are mounted onto the engine. A poor engine or pump alignment can cause these problems.

    That noise you are hearing when the boat idles could be the impeller banging against the wear ring which can also be a symptom of a poor alignment. Listen closely near the pump area when the engine is idleing on the trailer to find out if the noise is coming from the pump.

    To your last point, make sure the engine is aligned per the manual, make sure that all motor mounts have the shims in place between the engine and motor mounts and the bolts which hold the engine to the motor mounts are torqued to specs.

    It is all very true that the bolts should ALL be snugged in place before the bolts go through their torque sequence. Even if they were in a bind though, nothing should break. It is when the engine starts and high vibrations put even more stress on these weak links when things start to break. It has been my experience that poor engine AND ESPECIALLY pump alignments cause these mounting points to break.

    I am not saying that this is the only solution to this type of problem, I am saying that this is worth looking into (especially when you do not know what the previous owner did or did not do to the craft before you bought it).

  7. #7
    mudslanger's Avatar
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    Salty when you put bolts in a bind and put repeatedly bouncing stress on them they will break. it has been MY experience from these waverunners at my shop that i have repaired from this same issue. A fastener such as a bolt that relies on head pressure to secure an object in place will do just that but added side pressure can cause that fastener to fail. also bolts that are not torqued properly where the threads are dirty not letting the head to be torqued properly can cause breakage. just some FYI for you.

    To the original poster i hope you find the issue what ever it may be. always glad to help.

  8. #8

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    I agree with you Mudslanger, and in a manner of speaking, we are saying the same thing in different ways. Putting torque on the bolt within engineering limits should not break it. It is what that these components are subjected to once the engine is started is what really causes the damage.... be it bouncing, vibration, wrong torque specs, etc.

    The real point here is that we do not know what this boat has been subjected to, and neither does the owner. So what I am suggesting is that he makes sure that all the important components are put back together the way it was designed, align everything properly, put all the bolts in, snug down and torque to specs. Hopefully his problem will go away.

  9. #9
    mudslanger's Avatar
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    well if people on this forum would work with each other to help solve the posters problem this would be a much better place. i do appreciate the previous post and am not trying to argue but have posted in the past and some a$&% come in and say that is not the issue. that can rub the wrong way and causes strife. but i will stand on what i do know. when you posted even if they were in a bind though, nothing should break. it was taken as contradiction but what ever. catch yall later.

  10. #10
    GoFastGuru's Avatar
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    Quote Originally Posted by mudslanger View Post
    well if people on this forum would work with each other to help solve the posters problem this would be a much better place. i do appreciate the previous post and am not trying to argue but have posted in the past and some a$&% come in and say that is not the issue. that can rub the wrong way and causes strife. but i will stand on what i do know. when you posted even if they were in a bind though, nothing should break. it was taken as contradiction but what ever. catch yall later.
    do what slinger says and find green loctite and you should be fine

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