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  • 3 speed with reverse

    need some instruction with putting 3+R in a 4 speed case thanks

  • #2
    What year of transmission, meaning tin primary, 65-69 or 70 up? There are a couple of reverse gear sets that are not interchangeable, so make sure the gear sets match. Also if your case is not machined for the reverse idler gear, it will need to be machined.

    I run a 1969 flh sidecar bike with a 3R transmission that I built and installed. I am going to put the 4 speed back into the bike because I put a lot of miles on it and the 4 speed would be the better choice for an over the road transmission. So what are you going to use the bike for, daily runner or very seldom ridden, it makes a difference?

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    • #3
      I wouldn't do it unless necessary.
      The 3-spd 2.71:1 first gear is substantially worse (lower number) than the 4-spd at 3.00:1, which is the opposite of what you want for more weight. The 3-spd's 1-2 shift falls off a cliff with 45% RPM loss (4-spd is 39%), the 2-3 is very bad at 33% ( 4-spd is 19%). This means you have no downshift at higher speeds - you can't reach second without buzzing the motor.
      These work as OEM gearing because the engine (and transmission?) sprocket is smaller.

      4-spd: 3.00, 1.82, 1.23, 1.00
      3-spd. 2.71, 1.50, 1.00
      Last edited by kitabel; 10-26-2022, 11:31 AM.
      The Linkert Book

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      • #4
        I prefer 3R for around town over 4spd

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        • #5
          I run a 21 tooth engine sprocket with a 23 tooth trans sprocket with my 3R trans, I cannot downshift from 3rd gear down to 2nd gear until I go down to 20-25 mph, this makes it a pain once in a while like going up a hill behind a slower driving car or in a hilly area in general. As far as power is concerned, It is not an issue and you get use to riding with the 3r trans over time. The 3R trans is also a sliding gear trans that grinds once in awhile, like a Model A or a tractor. I had a couple of issues with my trans that ended being a clutch issue, the clutch has to be adjusted almost perfectly.

          My bike pushes very easily and I only have one leg, so the 3R is coming out of my bike, mainly because of the 3-2 downshift. I get 35 mpg without a passenger, 30 mpg with my wife in the sidecar and 25 loaded down with camping gear for 2 separate people and my 200 lb nephew.

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          • #6
            Thanks all for your help. Putting together a trike with a shovel motor. I think I would like the idea of having reverse but am almost talked out of it. This bike would be used on occasion for small trips and most likely ridden on back roads. Have put together many rachet top four speeds.

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            • #7
              3+r is an aquired taste and a new skillset. You must give it time to appreciate it. It helps to have other 4 speed bikes available.

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              • #8
                Big engine, low speeds,good low RPM power: fewer gears, farther apart (truck, cars 70 years ago)
                Small engine, big cam, high speed, bad low RPM power: more and closer gears
                The Linkert Book

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                • #9
                  I built my 44UL specifically for sidecar use 45 years ago and used a 3&R transmission. It is still in the same configuration and still my favorite bike. It has been on thousand mile trips with a passenger over high mountain passes (for example Red Mountain Pass, 11018 ft) here in the Rockies. At times a 4 speed may have been nice but it has always performed just fine within its limitations and I would never change it.
                  Robbie Knight Amca #2736

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                  • #10
                    Originally posted by shovelheadstan View Post
                    Thanks all for your help. Putting together a trike with a shovel motor. I think I would like the idea of having reverse but am almost talked out of it. This bike would be used on occasion for small trips and most likely ridden on back roads. Have put together many rachet top four speeds.
                    I would go for the 3R for your trike. Like I commented earlier, you will get use to the 3R trans like staying in 2nd gear from time to time to stay within the power curve of the engine so you are not lugging in 3rd gear. I have put many happy miles on mine and it took roughly a couple hundred miles to get use to the trans.

                    ps: Have you thought about a 5 speed because reverse gear can be added without effecting the forward gears?

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                    • #11
                      Thanks all for the comments. I think I'm going to pull the trigger and go with the 3R. I have been in situations with a two wheeler and wished it had reverse. Next question, where to source transmission parts. trying to run cone shovel primaries with electric start.

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                      • #12
                        Look at the Shovelhead forum on here, member Ryan just bought a pile of parts with a 3&R in it.
                        Robbie Knight Amca #2736

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                        • #13
                          Originally posted by Rubone View Post
                          Look at the Shovelhead forum on here, member Ryan just bought a pile of parts with a 3&R in it.
                          Yes, I have a 3R transmission for a cone shovel. It only has about 2k nautical miles on it, now that is just a guess because I am not sure how many miles it is from the Ohio river, down the Mississippi river to the Gulf of Mexico. LOl
                          Last edited by ryan; 10-28-2022, 01:38 AM.

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                          • #14
                            Ryan, is the 3R for sale

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                            • #15
                              Originally posted by shovelheadstan View Post
                              Ryan, is the 3R for sale
                              I sent you a private message. Take care

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