1. Some members were not receiving emails sent from XJbikes.com. For example: "Forgot your password?" function to reset your password would not send email to some members. I believe this has been resolved now. Please use "Contact Us" form (see page footer link) if you still have email issues. SnoSheriff

    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.

MAC 4-1 with gaskets

Discussion in 'XJ Technical Chat' started by Kylew11, Jul 25, 2011.

  1. Kylew11

    Kylew11 Member

    Messages:
    55
    Likes Received:
    0
    Trophy Points:
    6
    Location:
    Victoria, BC
    I haven't had a problem with the stock exhaust to date other than the fact that it rusted out. I got my brand new MAC 4-1 kit to install. I also had new exhaust gaskets. Upon firing up the bike it was immediately obvious there's a leak out the gaskets. does anyone know exactly which gaskets belong on my bike to properly seal a mac 4-1 system? are they the same gaskets as with the stock system? any and all input will help.
     
  2. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,097
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    should be the stock gaskets, loosen it back up and give it a few wiggles, maybe it isn't seated right
     
  3. lostboy

    lostboy Well-Known Member

    Messages:
    1,225
    Likes Received:
    324
    Trophy Points:
    83
    Location:
    Tillsonburg, Ontario, Canada
    When I replaced my MAC 4 into 1 I doubled up on the gaskets and used hi temp copper silicone to get a good seal. Like Polock said make sure the pipes are centered. Be careful not to over tighten the flanges they bend easy.
     
  4. Kylew11

    Kylew11 Member

    Messages:
    55
    Likes Received:
    0
    Trophy Points:
    6
    Location:
    Victoria, BC
    I ordered some of the aftermarket gaskets.. From what I can see they will not work. The OEM ones are flat copper gaskets, correct?. Anyway, I didn't expect them to differ by much but these aren't Functional for me at all. Does someone have a pic of OEM vs. Aftermarket?
     
  5. Kylew11

    Kylew11 Member

    Messages:
    55
    Likes Received:
    0
    Trophy Points:
    6
    Location:
    Victoria, BC
    Never mind, I found it.. http://www.xjbikes.com/Forums/viewtopic ... haust.html

    Has anyone else used the aftermarket gaskets with the Mac 4-1 system?? The metal OD of the gasket is spot on with the OD of the header so in my opinion it's guaranteed to leak. If someone can inform me otherwise I would appreciate it. Also, if i were to order the OEM gaskets, is the OD of those the same as the aftermarket ones? does anyone know the size? Meanwhile, I'm trying to find some gaskets locally so I don't have to wait another week to ride my bike that's been out for 5 weeks already!! BOO
     
  6. bigfitz52

    bigfitz52 Well-Known Member Premium Member

    Messages:
    21,283
    Likes Received:
    418
    Trophy Points:
    83
    Location:
    Rural SE Michigan 60 miles N of Motown
    There are PICS of BOTH styles in my how-to you posted the link to.

    Other than material and "style" of construction, dimensionally they're virtually identical. They kind of have to be to be interchangeable.
     
  7. Kylew11

    Kylew11 Member

    Messages:
    55
    Likes Received:
    0
    Trophy Points:
    6
    Location:
    Victoria, BC
    so my next question is, have you installed a mac 4-1 system using the aftermarket gaskets or the oem ones? I have the aftermarket ones and the diameter of the aluminum outer ring is the same size as the flange of the header. It will be impossible to create a seal against that. the stock header has a nice flat face that mates well with the element contained within the two rings, I just wish the new exhaust system was that easy. I just need someone with hands-on details about this system with the two different gaskets. Since there shouldn't be any difference between each gaskets in terms of OD, I doubt the copper OEM ones will work properly either.. i'm going to pick up the OEM type after work.. i'll post some pics later to help illustrate the point.
     
  8. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,097
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    i used the ones from Len "chacal" and never gave it a second thought
     
  9. Kylew11

    Kylew11 Member

    Messages:
    55
    Likes Received:
    0
    Trophy Points:
    6
    Location:
    Victoria, BC
    you used the OEM ones or the Aftermarket ones? and you used them on a MAC 4-1 system? the ones I have now are the aftermarket ones from Len. The problem isn't in the gasket, its that the mac system has a different mating face with the gasket. i'll post pics later to illustrate the point.
     
  10. wizard

    wizard Active Member

    Messages:
    5,282
    Likes Received:
    26
    Trophy Points:
    38
    Location:
    DEVON ENGLAND
    I always set the gaskets in clear silicone (both sides) makes a perfect seal, but can be peeled off next time.
     
  11. KrS14

    KrS14 Active Member

    Messages:
    1,642
    Likes Received:
    9
    Trophy Points:
    38
    Location:
    St Marys, Ontario
    I used the aftermarket gaskets when i put my MAC 4-1 on. It leaked when I first started it up, only cause I was being a pansy with the torque lol.

    Wrenched it down a bit more and it's sealed fine, the tabs didn't bend at all.

    Now i gotta find a solution to changing the oil without dumping oil all over the nice new exhaust (the actual 4 to 1 is right under where it would drip) lol.

    Figure i'll get some cardboard and bend it so it fits in between #2&3 headers, use it like a V type funnel into my oil pan. This is WITH the spin on filter adapter.
     
  12. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,097
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    there was no yamaha sticker on the bag so i guess they are after market, yes mac 4/1.
    something to look at is the angle that the pipe meets the head, if the collector end is high, that puts a space at the top of the exhaust port.
    before i had the bracket made i tightened the nuts till they just touched the flange and moved the collector end up and down till i felt the pipes being flush in the head, then block it up there and tighten the flanges
     

Share This Page