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6 speed tranny's for Harley's

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  • 6 speed tranny's for Harley's

    I'm putting new gears in my 4 speed ( 1984 Soft tail ) and a lot of people ask why I don't spend a little more and get a 6 speed tranny. I don't get this 6 speed stuff, I don't use the 4 gears I have most of the time. This whole idea of adding more gears to a bigger inch motor just seems backwards to me. More gears is usually to help an under powered engine. Having 100 plus inches and adding 2 more gears seems like a lot of extra weight and shifting with no real gain. What I'm doing is putting a lower first ( 2.60 in place of a 2.44 ) and upping my high end with a larger transmission sprocket and a smaller wheel sprocket. ( 24 and 49 tooth) This puts 1st very close to stock and a 4th cruising speed calculated at about 74 mph at 3100 rpm. Thats about 300 rpm less than stock.
    I just have an 80 inch engine and I think this gearing will serve me well on the street but I think if I were to drag race a 100 inch or bigger I would be tempted to go with a 3 speed. Any way, I was just wondering if any one here is racing the big inchers and what they are using transmission wise ? Also any comments from any one using a 6 speed ?

    If any one is interested, here are my new ratio's.
    primary - 1.54 / 1
    1st - 2.60 / 1
    2nd - 1.82 / 1
    3rd - 1.23 / 1
    4th - 1 / 1
    final - 24 - 49 front & rear tooth count


    Here are my old ratio's.
    primary - 1.54 / 1
    1st - 2.44 / 1
    2nd - 1.65 / 1
    3rd - 1.23 / 1
    4th - 1 / 1
    final - 23 - 48 front & rear tooth count ( stock had a 51 tooth rear )

    With my health the way it is, I was considering trying to find a tranny with a reverse in it. Then decided, naa. I want to keep first slowed down for when I get out in the National forests and such.

  • #2
    if you are not planing on racing it there realy dosent seem any point to the 6 gears. like ya said you have no need to stay in the power band just crose it.
    a reverse might not be too bad an idea, i dont know what they run $$ wise but on a big bike it could come in handy. i know they make them just dont know how much $$ it would be or if its werth the $$ to ya.
    man i gotta get another bike.

    Comment


    • #3
      On the lower displacement engines like your puny harley, true there isn't much point getting the 6spd, though on my IronHorse texas chopper running a 124 CI with alotta extra torque and zoom power it's nice to have the extra gears.....

      Comment


      • #4
        Originally posted by cruizer
        On the lower displacement engines like your puny harley, true there isn't much point getting the 6spd, though on my IronHorse texas chopper running a 124 CI with alotta extra torque and zoom power it's nice to have the extra gears.....

        And youll need them to catch the Honda's

        Comment


        • #5
          And youll need them to catch the Honda's

          ummm.... .......... dont you mean to TRY to catch the honda's.

          Comment


          • #6
            Originally posted by cruizer
            On the lower displacement engines like your puny harley, true there isn't much point getting the 6spd, though on my IronHorse texas chopper running a 124 CI with alotta extra torque and zoom power it's nice to have the extra gears.....
            I think you missed my point. On my 80 CI, I have enough extra power to spare that if I'm in 1st gear I'll skip second and go directly to 3rd, or if I'm in 2nd, I'll skip 3rd and go directly to 4th.
            On you're 124 CI, are you running all 6 gear's consecutively ? Its hard for me to imagine there being much difference between gears since the first five run up to a direct drive the same as my 4 speed, the only difference is the overdrive, I think its like .86 / 1 ratio. Do you know what the 1st gear ratio is on the 6 speed ?

            Comment


            • #7
              Keep the 4 and the kicker.

              Comment


              • #8
                your just cruzzzing along like it was ment to be ridden, i agree keep the 4.

                Comment


                • #9
                  my 1.5 cents

                  I'm not anything close to an expert about the two wheeled variety, in fact I'll go so far to say that I don't know squat about a bike unless its on dirt, and then I know just enough that is learned as boys on their toys playing in the mud, but IMHO, for most of the riding people will do, the 6 speed is 2 gears cooler than the 4, that's it If you put them side by side and said to me which one, of course I'd take the 6, whether or not the tradeoff would actually be worth it for a 6 clicker, well....... now that's using logic, and sometimes that stuff just don't belong, but at least I'd be able to say it had the 6

                  Comment


                  • #10
                    Hey Pete,
                    The need for a six speed comes in when the engine builder builds an engine with a very narrow power band. Some guys like a cam that is quick reving and builds power real fast so you get super quick acceleration but with that you loose power quick as well so time to grab another gear. Now on your mostly stock 80 incher that has a cam that builds nice power over a real wide range, if you were going to go after some ricers you would most definitely need to change the cam and rework the heads, change the rods and get that 6 speed. In 94 I won the Easy Rider horsepower shootout with my 80 incher and Skeeter Todd on the seat from Easy Rider(121hp at the tire). This thing would eat CBR 600s, but was no match for the CBR 800's.
                    Good luck,
                    Bulldog

                    Comment


                    • #11
                      I have a RevTech 4 spd in my '73 84 in. shovel. I have it overgeared (48t vs 51t rear). Cruises good. A little slow off the line, but worth the tradeoff to me. The OD is to lower RPM while cruising. My 4 1/2" stroke gives me enough torque to overcome the gap between 3rd & 4th. My $.02.

                      Comment


                      • #12
                        Originally posted by cruizer
                        On the lower displacement engines like your puny harley, true there isn't much point getting the 6spd, though on my IronHorse texas chopper running a 124 CI with alotta extra torque and zoom power it's nice to have the extra gears.....
                        You'll need all the help you can get just to try and keep up with the Suzukis.

                        Maybe you could rip a 13 speed tranny out of a Kenworth!

                        Comment


                        • #13
                          The point missed is extra gearing means lower RPM's which equate to longer engine life. The extra gearing evolved due to interstate travel. Plus there is no law that says you have to use all six gears all the time.

                          Those who are more mechanically inclined will understand what I have said..

                          Stick with your three speeds and keep that puppy wound tight.

                          Comment


                          • #14
                            Originally posted by Bulldog View Post
                            Hey Pete,
                            The need for a six speed comes in when the engine builder builds an engine with a very narrow power band. Some guys like a cam that is quick reving and builds power real fast so you get super quick acceleration but with that you loose power quick as well so time to grab another gear. Now on your mostly stock 80 incher that has a cam that builds nice power over a real wide range, if you were going to go after some ricers you would most definitely need to change the cam and rework the heads, change the rods and get that 6 speed. In 94 I won the Easy Rider horsepower shootout with my 80 incher and Skeeter Todd on the seat from Easy Rider(121hp at the tire). This thing would eat CBR 600s, but was no match for the CBR 800's.
                            Good luck,
                            Bulldog
                            Thanks Bulldog;
                            Thats the kind of stuff I was after. I was thinking along the lines of a heavy load or pulling a trailer, but I've been loaded very heavy with my 80-CI 4-speed and pulled a trailer,(not at the same time though ) and did just fine with 4. On the speed end only, it would seem that unless you plann on 300 mph, 6 speads is not really needed.
                            The only argument I would have with you're explanation,( and it is a factless argument since I never ran a big inch 6 speed ) Is that you would wast too much time shifting gears to keep it in a narrow rpm range to win races.
                            How tight of a power band can you really get on a big inch Harley ?

                            I did recam mine, first with an ev-46 then changed to an ev-13 witch I like a lot better. Its more of a dresser style cam, a lot of low and mid range performance. I'm also running 10 /1 pistons but that is not by design, thats all I could get in a 15 thousanth over (long story, I think I have the last set in existance) , I wanted to keep a low compression. The 10 / 1 pistons CCed to only 9.3 / 1 when it was finnished so I'm OK with that.

                            Comment


                            • #15
                              Originally posted by moe1942 View Post
                              The point missed is extra gearing means lower RPM's which equate to longer engine life. The extra gearing evolved due to interstate travel. Plus there is no law that says you have to use all six gears all the time.

                              Those who are more mechanically inclined will understand what I have said..

                              Stick with your three speeds and keep that puppy wound tight.
                              You don't understand these " harley " types. Lower RPM = Lower Exhaust Noise. They need em wound tight to be LOUD !!!!


                              Side Note - I own a Harley - fully restored STOCK 1972 XLH 1000 - not ridden much if at all - it's a Harley after all!

                              Comment

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