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New Meat

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  • New Meat

    Hey folks,new guy here.
    I'm working on my first F head,1919 police. Probably be drivin' y'all crazy with questions and ideas.

    My current dilemma is finding 20 over pistons. Anybody ever thought of using Tecumseh pistons? The HH80,HH100 and OH140 have the same 3.12" bore. Been trying to get the info on pin dia and comp. height. I've owned two OH Tecumseh motors and I know from experience they are tough as nails.

    Next ?
    IF I do wind up using such a beasty would it be a good idea to omit the oil ring.

    Thanks, SW

  • #2
    I'm motor challenged, SW but I have owned a number of early Js. Cylinders, and top end work is a problem as there are unique issues with pocket valve motors, blind bore cylinders, and cast iron pistons. Apparently, many Cannonball riders have found solutions to those problems, but they seem very reluctant to share the knowledge. You should check out this 1919 build by our fellow AMCA member, John who very graciously shared his discoveries, and detective work on this thread:

    https://forum.antiquemotorcycle.org/...Harley-Model-F
    Eric Smith
    AMCA #886

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    • #3
      Talk to Dale at Motion Machine in Lynchburg VA. He shows a video doing a couple of JD cylinders in a CNC machine. Does both in under a minute. I think he does a lot for the Cannonball guys. You can Google them and it should come up.

      Tom (Rollo) Hardy
      AMCA #12766

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      • #4
        I'm capable of doing the work. I may have to farm out the initial bore because of the huge ridge at the top of one of the cyls. I have micrometer hones and lots of measuring devices to finish up with. It's allocation of parts that is the problem.

        There is a used piston assembly on fleabay. Reckon I'll have to buy it to get the measurements then throw it in the trash.

        Working on the generator today. Had to make the screw that retains the interrupter plate. 1/4-32 countersunk head is not something you're gonna get at Ace hardware.

        I love my ol' atlas lathe!!

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        • #5
          I'm trying to follow along here
          You said "Had to make the screw that retains the interrupter plate. 1/4-32 countersunk head is not something you're gonna get at Ace hardware."
          I don't know what the interrupter plate is. Got a part number for it as well as the screw you mentioned? I'd like to be able to understaned which part your referring to.
          Thanks

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          • #6
            HI, welcome to the forum. Like eric said, I have built one of these from a starting point of zero knowledge on these early F's and J's. I am no expert although there are a few genuine experts on here, however if you have any questions that I can answer I will gladly chip in. Mine is a 20F so one year later although the differences (i think) are small.between '19 and '20.

            John

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            • #7
              The centrifugal switch on the back of the 235 generator that disconnects it from the battery when the engine stops. The plate that holds the weights is mounted to the back end of the armature shaft with a countersunk screw. That screw is 1/4"-32 RH thread. A monkey with tools had cross threaded that screw sometime in the past and booggered it up so it wouldn't tighten the plate and the whole assembly was flopping around in there.

              The screw slot was pretty McF***ed also.

              I used a 1/4" grade 5 hex head bolt with a couple inches of unthreaded shank and threaded the shank to 32 tpi then cut the counter sink head and screwdriver slot.

              I've had to make a lot of parts for this old beater. Some of the parts could be bought but hell,what's the fun in that.

              I'm a clockmaker by trade these days and making parts for 100+ year old machines is an everyday thing.

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              • #8
                Mine is an "F" so no generator so I cant help with any tips.

                Have you any pictures to post? I am sure lots of folks would love to see some even if it is just a pile of parts.

                John

                Comment


                • #9
                  Originally posted by TechNoir View Post
                  HI, welcome to the forum. Like eric said, I have built one of these from a starting point of zero knowledge on these early F's and J's. I am no expert although there are a few genuine experts on here, however if you have any questions that I can answer I will gladly chip in. Mine is a 20F so one year later although the differences (i think) are small.between '19 and '20.

                  John
                  Thanks John!
                  Yeah man,I saw your old bike. What a mess when you got it.
                  Fortunately the one I'm working on is in pretty good shape other than many miles of use and monkeys with tools.
                  I'm thinking it ran until worn out then repainted and loosely assemble for display only. Cylinders are still stock bore and the bottom end is worn slap out. It will be getting new shafts and rollers as well as the top end rebuilt.
                  Unfortunately I'm doing this for someone else and have to give it back once it's done.

                  Comment


                  • #10
                    Originally posted by scooterwrench View Post
                    Yeah man,I saw your old bike. What a mess when you got it.
                    That was not a mess; that was beauty. That's the way you want to find them in the world of antique motorcycles.
                    Eric Smith
                    AMCA #886

                    Comment


                    • #11
                      Originally posted by exeric View Post
                      That was not a mess; that was beauty. That's the way you want to find them in the world of antique motorcycles.
                      This is what this ol' girl looked like when she came in;
                      20200115_112950_HDR1.jpg
                      20200115_112820_HDR1.jpg

                      This is her know;
                      20200224_102213_HDR1.jpg
                      20200224_102230_HDR1.jpg

                      I'm trying to knock as little of the rust off as possible,gotta leave a little stank on her.
                      Last edited by scooterwrench; 03-31-2020, 02:18 PM.

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                      • #12
                        looks like a fairly complete, nice solid project.
                        pretty sure the seat is a 21-23 type. my 19J has the exposed springs while yours has the later enclosed type.

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                        • #13
                          "The centrifugal switch on the back of the 235 generator that disconnects it from the battery when the engine stops. The plate that holds the weights is mounted to the back end of the armature shaft with a countersunk screw. That screw is 1/4"-32 RH thread. A monkey with tools had cross threaded that screw sometime in the past and booggered it up so it wouldn't tighten the plate and the whole assembly was flopping around in there."
                          Thanks for the clarification. I'm up to speed now.
                          Good luck with the project, a great piece to start with.

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                          • #14
                            The story I got from the man that owns it is he traded a station wagon for it 50yrs ago and has kept it in his garage since and never heard it run.
                            That was my task but after firing it up I discovered the front cyl. was cracked just below the head area. Sprayed oil on the downtube.
                            Pulled the motor and front cyl. to find the rod could be shaken up and down about .010" Pulled the bottom apart and pretty much everything is worn out. I think I can reuse the right side bushing with a new pinion shaft and the left race with a new sprocket shaft and .003 over rollers. Competition Dist. is gonna love me!

                            Well the Tecumseh piston idea was a bust. The wrist pin could be made to fit but the compression height is almost 5/8" too low,reckon I'll be making pistons too. Anybody got an 8" piece of 3.5 2618 aluminum round stock laying around?

                            Comment


                            • #15
                              Speak to Jon Neuman at Sagebrush Cycle in Texas about pistons.

                              John

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