1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

Exhaust Header Support

Discussion in 'XJ Technical Chat' started by sybe, Jul 8, 2019.

  1. sybe

    sybe Active Member

    Messages:
    576
    Likes Received:
    138
    Trophy Points:
    43
    Location:
    NYC - Brooklyn
    So I have this recurring issue where i keep breaking exhaust nut collars. The mufflers i am using are from a Harley that were shorted with a slash cut. I am thinking the larger diameter muffler is putting stress on the exhaust collars and it might be causing it to snap over time. So in stead of using the stock screw posts/studs, would it be safer to remove the stock studs and use bolts. My thinking is the stock studs dont give me much play when installing and is where most of the stress comes in. However using normal bolts scare me, i dont want to strip the threads on the head or snap a bolt.

    I also want to add the mufflers are welded on.
     
  2. sybe

    sybe Active Member

    Messages:
    576
    Likes Received:
    138
    Trophy Points:
    43
    Location:
    NYC - Brooklyn
    Here is a pic of the exhaust.
     

    Attached Files:

  3. jayrodoh

    jayrodoh YimYam Premium Member

    Messages:
    2,522
    Likes Received:
    1,102
    Trophy Points:
    113
    Location:
    Cleveland
    I wouldn't think the weight of the mufflers would affect it if you are still supporting the exhaust properly in the rear. Do the exhaust pipes sit flat against the head or has changing the mufflers moved the exhaust up or down in the rear? That's a lot of leverage on the little studs if you grab the exhaust from the rear and move it up and down. If it was not sitting flat against the head you would have some movement with might be breaking things as you ride.

    Bike is looking good man!
     
  4. Chitwood

    Chitwood Well-Known Member

    Messages:
    866
    Likes Received:
    374
    Trophy Points:
    63
    Location:
    Fort Atkinson, Wisconsin
    Are the mounts in the rear still factory rubber for the muffler hangers? Do you have rubber or solid engine mounts? Perhaps the engine mounts have worn allowing excessive movement putting undo stress on the collars/studs? Just thinking out loud. Mine likes to break right in front of the Harley mufflers I put on my 650
     
  5. sybe

    sybe Active Member

    Messages:
    576
    Likes Received:
    138
    Trophy Points:
    43
    Location:
    NYC - Brooklyn
    Thanks! thats the bike before the r6 front end swap. I went to take her out yesterday for a test ride but noticed the collar broke during my pre-check. When I unhook the rear mounts the exhaust drops so there is movement and proper support. When i install the headers they sit flush on the head. Its not a perfect fit. When i install the exhaust i have to keep everything loose and then wiggle the collector with the mufflers attached to make them settle in and fit properly and then go tighten everything up.

    I have rubber mounts all around. The engine mounts are still in good condition. I actually inspected all of the engine mounting points this past weekend. Except for some skuzzy looking bolts everything is in good shape.

    The collar that broke is on #1 and the previous one was #3. When I install #1 header, I install it with the collector and muffler already attached. #2 header is then installed and is typically hard to get on and aligned up with the collector. I have to keep #1 header and the muffler mount loose to jiggle #2 on. I can see this process putting force on #1 and making the collar snap.

    Would I be better off losing the stock studs and just directly bolt the collars to the head? Losing the studs will give me more wiggle room.
     
  6. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    Is the mounting bolt for the collector in place and tight? That's where most of the weight in the system is.
     
  7. sybe

    sybe Active Member

    Messages:
    576
    Likes Received:
    138
    Trophy Points:
    43
    Location:
    NYC - Brooklyn
    Not sure which mounting bolt. I have 4 for the headers 1 for the cross member and 2 for the mufflers which are defunct. If i am missing one that might be why its breaking.
     
  8. jayrodoh

    jayrodoh YimYam Premium Member

    Messages:
    2,522
    Likes Received:
    1,102
    Trophy Points:
    113
    Location:
    Cleveland
    That’s originally a maxim 650? There is no collector mounting bolt. Hangs at the engine and two points in the back.
     
    k-moe likes this.
  9. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,093
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    with two mounting points, the weight of the mufflers picks the headers up.
    whatever you do, don't use bolts. that's just asking for trouble
     
    sybe likes this.
  10. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    I oopsed. Though it was a 550.
     
  11. jayrodoh

    jayrodoh YimYam Premium Member

    Messages:
    2,522
    Likes Received:
    1,102
    Trophy Points:
    113
    Location:
    Cleveland
    Easy to do, especially with one that is modified. I’ve made my share too!
     
  12. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    Working 10 hours a day packing and hauling trash doesn't help my mental state.
     
  13. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,093
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    i would have thought the studs would have bent/broke before those collars
     
    k-moe likes this.
  14. jayrodoh

    jayrodoh YimYam Premium Member

    Messages:
    2,522
    Likes Received:
    1,102
    Trophy Points:
    113
    Location:
    Cleveland
    I wouldn't use bolts either. I wonder if you are tightening them too much? Using stock gaskets in there?
     
    sybe likes this.
  15. sybe

    sybe Active Member

    Messages:
    576
    Likes Received:
    138
    Trophy Points:
    43
    Location:
    NYC - Brooklyn
    I learned the hard way to only use OEM part/gaskets for the engine (except pods!). It was a very expensive lesson. I'll double check the exhaust gaskets and the exhaust port make sure there is nothing is in there causing an issue. i might be over tightening them too. I never really checked the torque specs for exhaust mounts.

    I had one stud break on #3 when i took off the stock exhaust for the very first time. I lucked out and half of the stud was still left and came out easily.


    I am sure the tank threw you off too.
     
  16. jayrodoh

    jayrodoh YimYam Premium Member

    Messages:
    2,522
    Likes Received:
    1,102
    Trophy Points:
    113
    Location:
    Cleveland
    7.2 lt lbs. Not much really. I was skeptical too when I put my bike together but never had a leak in the time I was able to ride it. If it was too tight and the heat cycles were expanding the pipe outwards etc. repeatedly I could maybe see one breaking.
     

Share This Page