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  • motor info:

    can someone explain to me when did they started to put Bonneville motors in Chiefs? Also what are the differences between the stock 74Ci. ?

  • #2
    Hi John 1940-1948 pistons different, slightly higher compression, heavier valve springs,more aggressive cams & followers special carb. mods.


    • #3
      I have seen a sales brochure from 1939 that lists the Bonneville option.

      339 "B" - $405.00
      339 "M" - $425.00
      339 "BM" - $450.00

      might have seen it on another forum.. just remember seeing the prices.


      • #4
        Magneto, larger cylinder head depth, high lift cams, 350 and up carb, or BONN Carb.


        • #5
          A mystery Folks,

          Is why the 1940 Motorcycle Parts Catalog lists Bonneville carburetor parts, when apparently Schebler didn't produce any.

          Any fossil evidence would be greatly appreciated!

          AMCA #776
          Dumpster Diver's Motto: Seek,... and Ye Shall Find!


          • #6
            Grabbed a couple of images from the 1936 - 1942 parts Catalog that I have.

            Bonneville Parts were offered for

            1939-1942 Chief 74"
            1939-1942 SS 45"
            1940-1942 45"

            Here are some of the screenshots

            Bonneville Cylinders.JPGBonneville Heads.JPGBonneville Manifold.JPGBonneville Pistons 74.JPGBonneville Heads SS.JPG

            They offered a Bonneville replacement for the Marvel Carb as well.

            Has anyone got a Bonneville Manifold, how different is it from the standard manifold.



            • #7
              Missed the attachment for the Carb

              Bonneville Marvel Carbs.JPG


              • #8

                That carb listing is similar to the '40 book (attached);
                The mystery is why there were Bonne carbs listed for '39-only twins before Linkerts were introduced for Indians in '41.

                Nobody seems to have ever encountered a Schebler stamped 'Bonne', and I have never encountered a 1 1/8" Schebler venturi.
                Listing in the '42 catalog as "replacements" is not such a mystery.

                I have never found much of a difference (other than cast iron vs aluminum) in Chief manifolds.
                Sport Scouts do vary greatly in porting, however.

                You confuse me about the 'Bonne' Marvel, as I do not see the '36-only Four model listed.
                ( But I have encountered those with differing jets... for what that's worth.)

                PS: All Bonnes I have encountered appeared to be typical for Linkert's '40 or later productions. If a '39 Indian Bonne Linkert exists, it would be nickel, with the "4-line script" on the side.
                Attached Files
                Last edited by T. Cotten; 04-15-2015, 11:55 AM.
                AMCA #776
                Dumpster Diver's Motto: Seek,... and Ye Shall Find!


                • #9
                  Thanks for the update Cotten, it fascinates me that a company has such poor record keeping, or I guess a lot of it was lost or throw out when the company ceased trading.

                  It's like doing a jigsaw that is missing some of the pieces and you have no picture to work from, so really don't know what is missing anyway.



                  • #10
                    Forensics is our task, Mike!

                    Parts books from many marques are questionable upon specifics, and the Indian '36-'42 is often cited for blatant flaws.

                    Once again, if anyone has examples from the 'fossil record' about pre-'41 Bonne's, please post us with clear photos.
                    As a student, I will greatly appreciate it.

                    AMCA #776
                    Dumpster Diver's Motto: Seek,... and Ye Shall Find!


                    • #11
                      I have found eight factors that comprise a Bonneville Indian. Plus, much higher top speed than the Standard Chief with 92 mph.
                      1. Magneto ignition
                      2. Cam measurement-Lobe Height=1.575" (standard=1.510")
                      Base Circle Dia=1.100" (standard=1.110")
                      3. Cam Lifters and Followers.
                      4. Heads-3/4" reach to spark plug (standard-1/2")
                      5. Kickstarter pedal-11 tooth (standard 10 tooth). Kickstarter Gear-28 tooth (standard 32 tooth).
                      6. Linkert Carburetor-Stamped M-BONN, and I believe is larger than Standard Indian Chief. Linkert Stamped 350-352 will also work.
                      7. Heavier Valve Springs.
                      8. Bonneville Cylinders intake measurement different than standard Chief.
                      Last edited by Lonewolf_51; 06-03-2015, 12:26 PM.