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longest-run motorcycle engine

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  • longest-run motorcycle engine

    I asked the hillbilly at Jerome about this motorcycle, parked a few feet from his sawmill. He said it was a 1942 Harley 45. I'd only heard of the Harley 84 and Sportster, and was surprised they made a 750cc. I shouldn't have been -- this engine had one of longest runs of any motorcycle engine, from 1929 to 1973.

    What other motorcycle engines might have rivaled this longevity?

    Allan Ostling

    Phoenix, Arizona

  • #2
    Bmw?

    I'm guessing that BMW very well might have something to come close to that. Indian maybe?
    James Kilroy

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    • #3
      Sochiro Honda's horizontal singles are by far the most widely produced IC engines in the history of mankind. I personally owned a 1963 pushrod 90 and they're still in production today. The Chinese are copying them like crazy.

      OTOH, I'd love to have that Harley! That'd be a flathead BTW. Foot operated clutch with a 3 speed aka "suicide shift trans".

      Need an edit after thinking about Kilroy's BMW mention. Is the opposed twin boxer motor a pre WWII design? Memory escapes me, but I used to know!

      SP
      Last edited by pntrbl; 07-20-2007, 11:25 PM.

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      • #4
        That's my bike

        Deleted/erased-out
        Last edited by oldtiffie; 08-20-2007, 03:48 AM.

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        • #5
          About BMW (source Classic Motorcycles by Vic Willoughby)

          The first BMW was made in 1923. Opposite cilinders, integral gearbox and shaft drive.

          Designer was Max Friz, debarred from continuing to design aircraft engines by the Versailles treaty, and switched his talents to motor cycles.

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          • #6
            The true story about Max Fritz was he was told by BMW to design a motorcycle to keep the firm going as they had been banned by the treaty of Versailles from producing aircraft engines after the first WW1 spat.

            Now ower Maxie boy was a arrogant little bugger and though that designing motor cycles well well below him and flatly refused. No amount of pushing by BMW in the form of pay rises, incentives or the firing squad could move him.

            In the end they asked what they could do to keep him happy and get him to design thier new found fortune [ as yet unfounded ]. His answer was a stove.

            In the early 20's it was bloody cold in them Barvarian mountains and fuel and most things were short in a defeated Germany so BMW installed a stove in his office and ower Fritz went on to design one of the most longest running engine designs, After the Germans finished with it, it was passed over to Russia as the Ural, after the Russians finished with it , it was passed onto the Chinese and has only just been replace in the Chinese army by a 400cc single .

            So from 1920 when it was first designed up until 2005 it owes a lot to a cast iron stove.

            .
            .

            Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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            • #7
              I wonder if anyone could post photos of the innards of the HD KR 45 flat track racer engine. THey are almost jewel like.

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              • #8
                Originally posted by John Stevenson View Post

                In the early 20's it was bloody cold in them Barvarian mountains and fuel and most things were short in a defeated Germany so BMW installed a stove in his office and ower Fritz went on to design one of the most longest running engine designs, After the Germans finished with it, it was passed over to Russia as the Ural, after the Russians finished with it , it was passed onto the Chinese and has only just been replace in the Chinese army by a 400cc single .
                I saw this Ural at the gas pump an hour ago, owned by a middle-aged couple who had picked it up in Prescott two days earlier. I guess this must be the Chinese version you mentioned. It was 2WD with a shaft to the sidecar. That could come in handy on muddy roads, so I'm surprised this configuration is not more popular.


                Allan Ostling

                Phoenix, Arizona

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                • #9
                  Originally posted by aostling View Post
                  I saw this Ural at the gas pump an hour ago, owned by a middle-aged couple who had picked it up in Prescott two days earlier. I guess this must be the Chinese version you mentioned. It was 2WD with a shaft to the sidecar. That could come in handy on muddy roads, so I'm surprised this configuration is not more popular.
                  They sell those at a shop down the street from me. Guy had one out this winter in the snow. Didn't seem to be having any problem.
                  Gene

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                  • #10
                    H-D used many of the 45s as trikes fot meter maids, etc, Very gool!
                    Also in WWII.
                    Last edited by flylo; 06-03-2013, 03:24 PM.

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                    • #11
                      Originally posted by heavysteamer View Post
                      I wonder if anyone could post photos of the innards of the HD KR 45 flat track racer engine. THey are almost jewel like.
                      Hmmm, I don't have pictures, but I usd to race a 1946 WR. That was the factory 45 cu. in. racer that was the predecessor of the Model KR.

                      They shared many similar characteristics. They both had much larger cylinder fins than their civilian counterparts, which would have been the WL and K, respectively. They also had larger intake and exhaust valves and used a 1-1/2" ID carburetor.

                      The valves on both engines were inclined a few degrees towards the cylinder to assist in airflow and the tops of the cylinders were relieved down to the level of the first piston ring, again to aid airflow.

                      The WR used Dow metal pistons and crankcases. Dow metal is roughly 50% magnesium and 50% aluminum. This was somewhat lighter than pure aluminum. I don't know about the crankcase metal in the KR but I do know that they used Dow metal in their pistons.

                      Both machines had roller bearing top end bearings like the civilian models but the main and cam bearings were all ball bearing. Both machines had magneto ignition and made use of rather low compression, probably less than 6:1. Harley found out that the flatheads ran very well with low compression so long as the airflow was properly designed.

                      Both machines used what were called "horsehoe" valve lifters" instead of the standard round roller type that Harley used on the civilian models. These gave increased valve duration for racing. They wore out rather quickly, however.

                      These machines were very competitive against the Indian racers which were their main competitors at the time. Both brands did well on Class C tracks until the advent of the Tiger Triumphs and BSA Gold Stars, at which time their dominance was over.

                      Nonethelless, a complete, running example of either a WR or KR would be a valuable unit at this point in time. They are as rare as hens' teeth.

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                      • #12
                        Actually BMW licensed the boxer engine design from Douglas. ABC also licensed the design from Douglas. The ABC company had made Sopwith aircraft and at the end of the war found that demand had dropped so much that they went into motorcycle manufacture and, like BMW, looked for the best engine design and licensed it from Douglas.
                        "Patriotism is the last refuge of a scoundrel"

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                        • #13
                          That Don Robertson sure has a lot of junk.
                          I really like his International KB-12 truck.
                          Is Pedro the mule still alive?

                          --Doozer
                          DZER

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                          • #14
                            What other motorcycle engines might have rivaled this longevity?
                            My motorized bicycle is a clone of a 1940's german design (As best as I can tell) where the only signifigant change (other then thinner gas tank and other cost saving measures) is they now have a slanted sparkplug hole for higher compression. Although not sure about what the cylinders used to be, they now use chrome lined aluminum. Kit is still being sold today by many manufacturers.
                            Last edited by Black_Moons; 06-03-2013, 04:03 PM.
                            Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                            • #15
                              Originally posted by jep24601 View Post
                              Actually BMW licensed the boxer engine design from Douglas. ABC also licensed the design from Douglas. The ABC company had made Sopwith aircraft and at the end of the war found that demand had dropped so much that they went into motorcycle manufacture and, like BMW, looked for the best engine design and licensed it from Douglas.

                              I was not aware of any formal license... but you can see the obvious similarity in engine layout..


                              P1010017 by aardvark_akubra, on Flickr

                              .......this was my 1952 Douglas 80+, since sold.

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