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  • Special muffler angle?

    Hi all. I've managed to get hold of a set of OEM headers with the plan of returning my SF back to 4-2 instead of the 4-1 it has fitted at the present. The headers have had the mufflers cut off. There is just enough pipe left to weld another piece of tube on so I can attach some slip-on mufflers. Could one of you Special owners tell me the degree of angle at which the mufflers are from the headers?

    Rob
    Rob
    XS Eleven SF
    Could this be the finest Triumph Bonneville ever built ?
    (Cycle January 1979)

  • #2
    Tact weld them to pipe extension with muffs installed and rear hanger bolted up, then remove, TIG weld completely, and re-install while still hot. This keeps from any stress fractures of weld.
    81H Venturer1100 "The Bentley" (on steroids) 97 Yamaha YZ250(age reducer) 92 Honda ST1100 "Twisty"(touring rocket) Age is relative to the number of seconds counted 'airing' out an 85ft. table-top.

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    • #3
      Originally posted by robbo View Post
      Hi all. I've managed to get hold of a set of OEM headers with the plan of returning my SF back to 4-2 instead of the 4-1 it has fitted at the present. The headers have had the mufflers cut off. There is just enough pipe left to weld another piece of tube on so I can attach some slip-on mufflers. Could one of you Special owners tell me the degree of angle at which the mufflers are from the headers?

      Rob
      Hopefully, where the muffs were cut off, it was behind the crossover pipe. Slip-ons use a connector band. You should use the bands if you can to check out performance and angles. Harley Davidson has some excellent connector bands. Rather than weld, try the connectors if you can. I suspect that you are asking because the location of the cuts is not amenable of slip ons... If that is the case my suggestions are complete bunk.
      Skids (Sid Hansen)

      Down to one 1978 E. Stock air box with K&N filter, 81H pipes and carbs, 8500 feet elevation.

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      • #4
        Originally posted by motoman View Post
        Tact weld them to pipe extension with muffs installed and rear hanger bolted up, then remove, TIG weld completely, and re-install while still hot. This keeps from any stress fractures of weld.
        Thanks motoman
        I dont have any mufflers yet, plus I dont weld so will need to take them to a welder. Thats the reason I wanted to know the angle between headers and muff so I can give the headers to a welder so he can set the pipe to be welded at the correct angle. Then when I get some mufflers I can just bolt it all on to the bike.


        Skids I have barely an inch of pipe to attach another piece of pipe, but I get what you're saying and I think I will have a lil bit of scope to experiment with optium lengths the way Im proposing to do it. The piece of pipe that will be welded on to the headers will prolly be 6" in length. I was thinking of fitting a crossover pipe between the two, creating an H shape of the new tube section Im having welded on. Would that be benifical or is that putting the crossover pipe to close to the headers, as obviously the crossover on an OEM system is futher up the muffler.
        Rob
        XS Eleven SF
        Could this be the finest Triumph Bonneville ever built ?
        (Cycle January 1979)

        Comment


        • #5
          Originally posted by robbo View Post
          Thanks motoman
          I dont have any mufflers yet, plus I dont weld so will need to take them to a welder. Thats the reason I wanted to know the angle between headers and muff so I can give the headers to a welder so he can set the pipe to be welded at the correct angle. Then when I get some mufflers I can just bolt it all on to the bike.


          Skids I have barely an inch of pipe to attach another piece of pipe, but I get what you're saying and I think I will have a lil bit of scope to experiment with optium lengths the way Im proposing to do it. The piece of pipe that will be welded on to the headers will prolly be 6" in length. I was thinking of fitting a crossover pipe between the two, creating an H shape of the new tube section Im having welded on. Would that be benifical or is that putting the crossover pipe to close to the headers, as obviously the crossover on an OEM system is futher up the muffler.
          I think the location of the crossover is important, but I imaging just having one is better than not. I have pipes from a model H on a model E and the mufflers are different as is the location and configuration of the crossover. The crossover interfered with retracting the center stand and I had to remove the stand. I still have the stand for maintenance purposes, but not having one could be problematic with changing a rear flat tire while on a trip.

          I think you should wait to have the fabrication done until you get the slip-ons so you can mount them at the rear connections and measure the angles. There is probably more than one angle to consider as they are likely upswept and also probably not completely parallel to the frame, if you follow me...
          Skids (Sid Hansen)

          Down to one 1978 E. Stock air box with K&N filter, 81H pipes and carbs, 8500 feet elevation.

          Comment


          • #6
            Skids I think I will incorporate a crossover pipe, like you say prolly better with one than with out. But if anyone knows a problem with having the crossover pipe further back than factory please chip in. You're right, better to wait until I get the muffs, then I can set the mufflers at the correct angle with the footpeg hangers then getting the fabrication of the new pipe from the headers should be a breeze
            Rob
            XS Eleven SF
            Could this be the finest Triumph Bonneville ever built ?
            (Cycle January 1979)

            Comment

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