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ZMA Sprocket Gear ratio

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  • ZMA Sprocket Gear ratio

    I was going through the previous Overdrive Magazine, Nov 2003 issue, the topic was sprocket the rocket, there they have mentioned that if ZAM front sproket teeth is increased to 1 teeth or rear sprocket teeth in reduced to 3-4 teeth the max speed would be in range of 140kmph, the calculation is mentioned is as follow
    FT RT MS CFT MS CRT MS
    13 42 125 14 134.62 44 119.32
    FT-Front Teeth, RT- Rear Teeth, MS- Max Speed, C-prefix to FT,RT for changed,
    the Hero Honda Karizma which sports a 13T front and 42T rear sprocket and reaches a top speed of 125kmph. Increase the teeth at the front to 14 resulting in a ratio of 1.08 which ultimately increases your top speed to a 137kmph. On the contrary you want better acceleration but are not so concerned about the top speed achieved then increase the rear sprocket size to 44T which gives you a ratio of 0.95. This gives you better acceleration but reduces your top speed to a 119kmph.

    This calculation theoretically looks current, but do we really get any boost in real life changes, would the engine be able to handle the extra speed due to the gearing change.

    Has anybody tried this on the ZMA, the ideal combination would be Stock ZMA front speocket with 13T and Ambition rear sproket which has 38T at the rear, this will make the top speed to 138.15 Kmph.
    Let me know if any body has tried and ZMA was able to sustain this extra speed load.

  • #2
    The Karizma hits abt 125kmh at 8000RPm , which I think means gearing is a tad short . However , that is riding single . When riding to Satara with my dad , the bike didn;t go pasr 117kmh as trhere are also a headwind . as such the at 117kmh the RPM was in the 7400/7500RPM range .

    For real world conditions which can be pretty varied , the stock set is best , however for thoe whose preferences deviate from the normal you can try small changes , I personally would like a 14T sprocket in front keeping stock 40T rear ( not 42T as printed in Overdrive ) for better cruising and maybe 2-3kmh incease in top speed .
    Man will occasionally stumble over the truth, but most of the time he will pick himself up and continue on.

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    • #3
      quote:Originally posted by Ricci
      ...When riding to Satara with my [u]dad , the bike didn;t go pasr 117kmh ...
      wow! @ 117kph with ur dad! thats cool!

      ~m~
      Destination Anywhere
      Praveen - Trivandrum
      Black Panther - Karizma
      http://s04.imagehost.org/0879/speedozma.jpg

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      • #4
        yeah Moonie , now you know who's the big daddy of bikers ( not bikes )here !!!
        Man will occasionally stumble over the truth, but most of the time he will pick himself up and continue on.

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        • #5
          !!!! u got a nice understandin dad!
          my dad will never sit wid me on my bike
          b/w ; i hv taken my zma to app 125 wid a pillion when we both were sorta tucked in.. in normal sittin posture, it went till abt 120 or so

          My little big blog bunnypunia.blogspot.com

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          • #6
            yup , my dads one of the coolest dads around if not the coolest ....
            and a Bullet fan too !

            Anyways back to topic inhand , did anyone actuall resporckt their Karizmas ? I'm interested in real word results , whether it does gain a couple of kms a I think it should with slightly taller gearing( I know the theory , everybody knows it since OD published their story ) ....but with a different chain/sprocket size ( pitch is the right word ? ) ,you need to have a same sized sprocket or else chainge entire kit to say a CBZ one .
            Man will occasionally stumble over the truth, but most of the time he will pick himself up and continue on.

            Comment


            • #7
              u r right man
              i am looking for a suitable front sprocket for zma but in vain.is there any one who can help us on this matter?
              zma has the biggest front sprocket it seems.
              i found almost matching sprockets from other bikes,but then the chain won't fit properly or the sprocket is too thin to accommodate the # 520 chain of the zma.
              i think i have to get a new chain set of the CBZ and then search for a suitable front sprocket.
              whst do you say guys?
              And Ricci,don't drive that fast with any pillion rider unless the roads are clear.You see,anything can happen in a split second.If any of ur loved ones get involved, you will never be able to forgive yourself for the rest of your life.Drive safe ok?
              ride safe 4 ur family
              [img][img]http://img.photobucket.com/albums/v6...ZK5busaaaa.jpg

              Comment


              • #8
                quote:Originally posted by ayush_sasi

                And Ricci,don't drive that fast with any pillion rider unless the roads are clear.You see,anything can happen in a split second.If any of ur loved ones get involved, you will never be able to forgive yourself for the rest of your life.Drive safe ok?
                [sarcasm on ]
                Na na , I was doing 115kmh right in middle of 10 ft wide crowded road with cattle , dogs and kids playing cricket everywhere . Oh I forgot to add there were also broken bricks , sand abnd gravel all over .[sarcasm off]
                I know how safe it is to speed accordingly , thanks for your concern . I was on Satara road where an RD350 might feel slow and clear for over 500metres of no/ sparse traffic ....

                leave the judgement to the rider . preaching safety after you'v ejust ridden with/observed others riding is one thing , trying to be a wise guy is another .

                PS : I'm also the slowest guy in my group , staying most further under the safety line ....and you ride bikes not drive 'em .

                Man will occasionally stumble over the truth, but most of the time he will pick himself up and continue on.

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                • #9
                  I will be refitting my ZMA with new sprockets i'm probably gonna be changing the front one to a 13T sprocket, only if you are changing both the front n rear sprocket is the whole set including chain n stuff required or else if changing a single sprocket the original chain can be reatined and used.

                  @ricci I came to knoe that ur the sprocket guru so am gonna be contacting you pretty soon for some queries hope you dont mind and can spare me ur no if possible would really help.
                  Also guys have seen ricci's driving whilst meeting fo rteh lonawala g2g last mnth havent seen anybody ride better and safer than him, keep it up ricci.
                  If BHP is power than I consider myself as GOD.

                  Comment


                  • #10
                    guys you can even try front cbz sproket which is 14 teeth and our bikes with 17 bhp cannot pull a smaller rear sproket especially if we have a 13front. so try ont cbz sproket it would give 137kmph. but your accleration would be dropped. i have broken my head whether i want acc or top speed... but never reached a conclusion... so just left it with stock ones... anyway some one try out and post the results.... mind you.. your milege wont be affected.

                    Comment


                    • #11
                      quote:Originally posted by zaidzaveri

                      I will be refitting my ZMA with new sprockets i'm probably gonna be changing the front one to a 13T sprocket, only if you are changing both the front n rear sprocket is the whole set including chain n stuff required or else if changing a single sprocket the original chain can be reatined and used.

                      @ricci I came to knoe that ur the sprocket guru so am gonna be contacting you pretty soon for some queries hope you dont mind and can spare me ur no if possible would really help.
                      Also guys have seen ricci's driving whilst meeting fo rteh lonawala g2g last mnth havent seen anybody ride better and safer than him, keep it up ricci.
                      Thnx for the acclaim ; flattering but I'm no guru yet .....
                      the ZMA has a 13/40 tooth front/rear combo . What do you want more of , acceleration or top speed ? Either ways , don;t expect a major jump .

                      Generelly its advised to change the entire set as differingf wear of chain & sprocket can wear out newer sprockets quickly too . Given the Karizma's chain is larger ( don;t know the actual size ) , other sprockets of desired no of teeth may not be of same size , but given the current power output I reckon a smaller chain like CBZ's would be fine .
                      Man will occasionally stumble over the truth, but most of the time he will pick himself up and continue on.

                      Comment


                      • #12
                        @ricci: Dont think you can use CBZ chain\sprockets on Karizma.
                        I had seen since the difference in size variation wont allow you to fit cbz onto karima.
                        I would like to know if some one has already done it and the changes afterwards [?]
                        Freeird-- Experience is what you get when you don\'t get what you want.

                        www.flickr.com/maniya

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                        • #13
                          @ricci would be getting custom sprockets made for my bike so dont think size or fitting will be an issue, thinking of gettin both front n rear 14T n 44 T sprockets made and then time the bike and compare them.
                          btw the stock ZMA sprockets are 13T n 42T n not 13T n 40T.
                          If BHP is power than I consider myself as GOD.

                          Comment


                          • #14
                            Nope , it is 13/40 stock , Overdrive's 42T published number is wrong . Open the chain guard and count yourself .
                            Also , 14/44 is shorter than 13/40 stock , assuming you want to gera taller .
                            Man will occasionally stumble over the truth, but most of the time he will pick himself up and continue on.

                            Comment


                            • #15
                              I guess so, he is aiming at taller gear only with his sort of configuration on same.
                              Freeird-- Experience is what you get when you don\'t get what you want.

                              www.flickr.com/maniya

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