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1942 Harley XA - Interesting M17 Linkert Problem

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  • 1942 Harley XA - Interesting M17 Linkert Problem

    Been slowly piecing together a "period custom" Harley XA for a few years now (or is it decades?). In final assembly now, drive train built, and waiting for sheet metal and a few other bits from my painter. (For the purists out there, yes, I know what isn't "correct" and original, and no, I haven't destroyed/removed a bracket, tab, or anything else that the next "caretaker" can't take advantage of if they want an "original bike.) While waiting, the bike is assembled enough that I thought I'd try to start it up. It started on the 4th kick! That said, it ran really badly, especially on the left side - SUPER rich and lots of black smoke!

    The stock Linkert M17 carbs use fixed 320 high speed jet with a "fixed" high speed needle screwed all the way in to shut off the needle hole from supplying any gas. Instead of a high speed adjustment knob, there is simply a plug that screws in on top of the needle to hold it in place. I was missing the high speed needle assembly for one carb so thought I'd just use a standard adjustable high speed needle in both (for consistency side to side) screwed all the way in. Seemed like an easy solution. What I hadn't noticed was that the bottom of the high speed needle knob actually hit the Linkert carb body slightly before the needle was fully seated all the way leaving the left side needle with almost a 1/16" to go and the right side needle about half that! Net-net, super rich running with the left side way worse than the right! It took me a while to find the problem but a quick chuck in a lathe to remove a bit of the bottom of the needle knobs fixed it. Starts easy and seems to run well. Still haven't ridden it, but should be soon. Not sure what other models use a fixed high speed jet, but something to be aware of if you go down the same path....

    Thanks.
    Chuck S.

    Started with this:

    XA Basket - 01.jpg

    XA Basket - 06.jpg

    As of this week:

    DSC09762.JPG

    DSC09766.JPG

    Linkert High Speed Needle Mod.jpg
    Last edited by wallaman; 07-23-2023, 07:50 PM.

  • #2
    Amazing progress, Chuck. There was a great thread on this, or the CAIMAG forum that showed the process of a German XA enthusiast who did incredible fabrication of rare XA parts. You're probably aware of that, but just wanted to give that guy recognition for his (somewhat) forgotten talent.
    Eric Smith
    AMCA #886

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    • #3
      exeric,
      The guy's name is Thomas and he is a great guy and amazing fabricator! He was VERY active and actually sponsored his own XA forum while he was restoring his XA (almost entirely from NOS parts!). We actually traded quite a few parts between us then, and he provided a number of reproduction parts that I used on this project. Unfortunately, once he was done with his restoration, his forum went away, and I believe he eventually sold his bike. I still stay in touch with him and hope to meet him one day in person if I get to Germany again. Definitely NOT forgotten (by you and me at least)!

      Comment


      • #4
        Amazing build Chuck. Nice work. A rare bike brought back from extinction!

        Comment


        • #5
          Beautiful work, Chuck! i love those upswept pipes.
          Steve Swan

          27JD 11090 Restored
          https://www.youtube.com/watch?v=ClUPIOo7-o8
          https://www.youtube.com/watch?v=LtuptEAlU30

          27JD 13514 aka "Frank"
          https://forum.antiquemotorcycle.org/...n-Project-SWAN
          https://www.youtube.com/watch?v=hNRB...nnel=steveswan

          https://www.youtube.com/watch?v=RSDeuTqD9Ks
          https://www.youtube.com/watch?v=bwlIsZKmsTY

          Comment


          • #6
            Steve,
            The upswept pipes are actually "stock" XA. Gives the bike that ADV look! LOL!

            XA - 13.jpg

            image_29725.jpg

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            • #7
              So made a bit more progress on my XA project and thought I'd share. Still waiting on a few more bits from my painter and the tanks still need some detail work (mounted them to be sure everything lined up as it should).

              DSC09813.JPG

              DSC09826.JPG

              DSC09818.JPG

              Comment


              • #8
                Nice work. I've seen quite a few of these civilianized but this is the first real bob job. Very well done. My friend has enough parts to build about four XA's.Very few parts exchange for regular BT items. Specialized for sure. Very cool!
                DrSprocket

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                • #9
                  RichO,
                  Appreciate your note! I'm not a "Military" guy from a collector's vantage point, and given what I started with, I was trying for what a guy just home from WWII who rode one of these would build from an Army Surplus sale. Sort of that post WWII "Bob Job" look, all the heavy stuff stripped off, etc. At the same time, I wanted to keep the "roots" of the bike intact. I'm pretty pleased with the result so far. Still a little ways to go, but hopefully won't be too long.

                  As for parts interchange, the bike is pretty unique from a "parts list" vantage point, but there are a lot of interchangeable/familiar assemblies. While not identical, a lot of the front end and electrical parts are basically the same. As for the drive train, a BMW guy would be a LOT more familiar with what's there

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                  • #10
                    So got final paint back from my painter. Time to put some test miles on!

                    DSC09983a.JPG

                    DSC09960a.JPG

                    DSC09970a.JPG

                    DSC09964a.JPG

                    DSC09990a.JPG

                    Comment


                    • #11
                      Really nice work wallaman. I admire the touches you did to make it yours. Enjoy the fruits of your labor.
                      Pete Cole AMCA #14441
                      1947 Indian Chief

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                      • #12
                        Very sharp looking XA. Definitely a one of a kind! Thomas is still around and frequents the XA forum (since he is the moderator) on FB which is still being used.
                        My XA is just about finished as well. Carb's were removed this past Fall, cleaned, some carb. parts replaced and put back on bike. Been south for the winter and now I'm back home which means I can get back on the bike to continue. Next will be adjusting the carb's.
                        To be continued.......
                        *****

                        Comment


                        • #13

                          Sambo42XA,
                          Hope you get your XA back up and running soon. Glad to hear Thomas is still alive and kicking! I'm not a FB guy, so no clue what goes on in that corner of the universe. Please tell him I said hello!

                          I've got a couple hundred miles on mine now and enjoying it more each time I ride it. Easiest starting motorcycle I think I've ever owned. Overall impression at this point is it is clearly a motorcycle that was "under development". Guess they all were at that point in time. Fun to ride, quick enough to keep up with traffic around town, but not a freeway rider - 65mph feels a bit like it's screaming! Would be nice to have a little lower rear end ratio for a little more top end. That said, guessing it was just right for the military purpose it was built for. And the transmission is a bit crude - well, it was 1942 after all. The "geometry" of the foot shift mechanism just seems off. Downshifts are fine, but upshifts require your foot to pull up AND back on the shift lever. All part of vintage hardware I guess... It's a shame Harley didn't pursue this design a bit further. Easy hand clutch with foot shift, auto ignition advance, shaft drive,.. My Knuckles could have learned a thing or two LOL! It could have been a winner...

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