exhaust nuts

Discussion in 'Sportster Models' started by dozerman, Sep 5, 2011.

  1. dozerman

    dozerman Member

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    Have had this rattle for about 4 days now and was about to drive me crazy. At first thought it was engine noise but sometimes it got louder and sometimes nothing at all. Was changing oil and primary today and gave her a good all around inspection and finally found my rattle. The exhaust flange was vibrating on the header pipe because both nuts are gone. Will any old nut with the right threads work or are they some special kind of metal?
     
  2. Breeze3at

    Breeze3at Well-Known Member

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    Any 5/16"x18 grade 5 or better, nut will be ok. I just use lock washers with them. Do not use a lock nut that has nylon or plastic as it will melt. To me, checking exhaust nuts is a routine maint. item, because they either seize to the stud or fall off if left unchecked.
     
  3. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    Best to put some high temperature anti seize on the studs and use 2 nuts per stud and lock the nuts together that should stop them getting stuck on or falling off

    Brian
     
  4. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    If you can find high grade stainless nuts...even better...corrosion due to heat and contact of dissimilar metals and moisture all conspire to make the hardware not last...:(
     
  5. mat 60

    mat 60 Senior Member

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    5/16x18.........Is the 18 the thread count per inch...Thats a fine thread isn't it.?
     
  6. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    It is a coarse thread 5/16x24 would be a fine thread

    Brian
     
  7. gator508

    gator508 Senior Member

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    I'm with Breeze on this one. You wouldn't think this would be a routine maintainence issue, but I have noticed these little guys loosen up after a few rides even though I've replaced the stock with ss and lock washers, tighten them to 120" pounds. The back cylinder is the main culprit on my bike.
     
  8. Hoople

    Hoople Account Removed

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    Did you have popping from an exhaust leak caused by the missing flange nuts?
     
  9. Jack Klarich

    Jack Klarich Expert Member

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    Check all the exhaust hangars as well, The stock H D exhaust nuts are a problem here, use the best grade 5-8 nut and lock washers you can find with some anti sieze to 10 ft lbs:s
     
  10. dozerman

    dozerman Member

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    Yes had some popping noise Just lately like the day before I found the nuts missing. Oh by the way it was the front cylinder. Got lock washers and double nutted both studs with grade 5 nuts. Will definitely keep an eye on this from now on.