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Thread: New tuning project. (72cc Torque motor)

  1. #1
    micah apriliaforum com
    Guest

    New tuning project. (72cc Torque motor)


    After years of trying to get the highest rpm and absolute max bhp out of the RS50 motor I have decided to try to build the best/most torquey motor possible. I now have no problem getting over 16 bhp at 14,000 rpm running out to 15,000 rpm. The problem is that for street use no one wants to launch their bikes at 12,000 rpm.....and parts wear out infinitely faster at high rpm. The most torque I have ever measured on my dyno was 6.4 ft/lbs from my RSW68....at 12,000 rpm. My new goal is to build a bad ass street motor with 8-10 ft lbs of torque and a redline (where useable power ceases) of no more than 12,000 rpm....probably 11-11.5K. This all makes good sense for you guys since most of use either the Arrow or Leo pipes, which are perfect for making a torquer street motor. I am going to cheat on the street aspect a bit and use race fuel and sky high compression but, to get what I need I must do what I have to. I am going to use either a TP72cc Double ring cylinder or a custom ported Malossi 68cc I have ordered since the ports are more conservative and it is a double ring which will not cause the huge frictional losses at the lower rpm the new project motor is designed for. Torque makes great wheelies and on tight tracks it is the bomb for racing as well.....for fast tracks the 15,000 rpm motor is a keeper. I will start on this when ever my new cylinder gets to America.

  2. #2
    suzuki1
    Guest

    whazzaaaaaaap


    Once my cylinder gets back from being bored over we're gonna do some testing, so get ready brudda. I'll bring the Red Stripe ... Hooray Beer!!! I got good power using the stock cylinder with stock clearance (sloppy), so I'm thinking this puppy should get some really good hp numbers with the overbore and race specs. Waiting on parts is killing me ... <img src=http://www.ezboard.com/intl/aenglish/images/emoticons/ohwell.gif ALT=":\">

    I'm determined to make our bike run with the heavy weights, so when your new parts get here you'll have all the data needed to get 20hp... or lots of torque.



  3. #3
    rs50rider
    Guest

    Motors


    How many motors do you guys have for the race bike? It seems that you are always building new motors. Its great for us to learn from. Have fun.

  4. #4
    suzuki1
    Guest

    different top-ends


    Every bike has the original tranny, but a few teams have extra top-ends as a backup if the bike seizes, and for testing.



  5. #5
    micah apriliaforum com
    Guest

    How many motors do I have?


    I have about 10 motors/bikes in the test fleet, they range from street bikes to 50cc, 68cc, 70cc and 75cc race motors. I will soon (in the next year) get my new MHR Replica motor built using the new Malossi/MHR parts that they will be selling in the coming year. They (Malossi) have a new MHR 50mm cylinder kit(78cc), pipe, 26mm carb, ignition and tuning parts coming in the next year according to the new PDF catalog I got recently.

    When all is said and done I just want two motors, my short-track and long track engines. I build customer race engines all week long....and publish most of what I do to them for consumption.

    PS: If anyone has an extra (blown up prefered) motor I would like to have a spare to build just in case.

  6. #6
    CrAiGrOx2002
    Guest

    Re: How many motors do I have?


    Micah u dont wanna try some doppler stuff do you, and/or MK, airsal etc, all these are available to me... and fast (nextday)

  7. #7
    Clarkie
    Guest

    Re: How many motors do I have?


    Micah, youve said that u'll either use a TP72 or a ported 68. i understand that porting increases power, but you're after tourqe, so how will your porting differ from if u were trying to find power?

  8. #8
    CrAiGrOx2002
    Guest

    Re: How many motors do I have?


    there are several differed methods of porting, for speed power/torque increasing squish, compression etc...

  9. #9
    speedfreak117
    Guest

    re:New tuning project. (72cc Torque motor)


    Wow I was just thinking about this last week after I was looking at a couple dirt bikes. I kept thinking if I could get their power band on my rs50 that would kick ass for the street. Are you going to build this project so someone like me who doesn't have a lot of tuning skills could do this too?

  10. #10
    micah apriliaforum com
    Guest

    Re: re:New tuning project. (72cc Torque motor)


    That is the plan.... Porting in this case just means getting the correct duration of the ports for the powerband you are after....and having a bunch of pipes around helps too. The Arrow pipe works best at 10,000 rpm so I am setting up the ports for 10-11,000 rpm and the jetting to suit. I may actually have to lower the port heights by cutting from the base of the cylinder....we shall see.

    BTW, did I mention I am getting a posotive displacement supercharger as well.....

  11. #11
    speedfreak117
    Guest

    re:New tuning project. (72cc Torque motor)


    whats that charger going on?

  12. #12
    BikerGeek
    Guest

    Supercharger


    The RS50/75 motor with some mod's should be able to handle a supercharger. What a killer idea!

    My only concern would be brakes and wheel bearings.

    Ride safe.

  13. #13
    micah apriliaforum com
    Guest

    Re: Supercharger


    I am going to try tu use it as it was intended. Posotive displacement "blowers" were invented to scavenge the case on two stroke deisel motors in the early days of engine design. Car guys then figured out that you could make them way less efficient to "boost" the motor. My plan is to use the blower as a replacemnet for the reed block itself since a posotive displacemnet device cannot backflow (like reeds cannot backflow). I am currently limited in bhp I can get from the motor due to reed area primarily.....this becomes obvious when 21mm, 24mmm and 28mm carbs are all making the same amount of power. The blower should allow me to feed a lot more air to the cylinder and get the power up, I am not actually planning to run much of anything in the way of true boost. This is my little two stroke winter project....do not expect to hear much about it before then.....way to busy right now with the normal stuff to start a whole new design project. If it actually works I will make public how to do it on your own motor. I just want to get way more power at a lower rpm to reduce wear on my endurance race motors. I do not actually have much hope that it will work well, just something different to play with. If it sucks on the two stroke you can bet it will find its way onto my incoming Rieju 125 Motard.....where I know it will kick ass.

  14. #14
    speedfreak117
    Guest

    re:New tuning project. (72cc Torque motor)


    bump. Just keeping this up on top.

  15. #15
    micah apriliaforum com
    Guest

    Re: re:New tuning project. (72cc Torque motor)


    I got my used TP72cc cylinder yesterday....the ports measured up pretty well for a torquer.....this cylinder should rock with either the Leo or the Arrow pipe. I am overboring it to 75cc and using a single ring TP piston for minimum friction. I am going for about 200 psi compression on the cylinder and head combo. I am not going to use the blower just yet...I have a lot of research to do to get that one right.

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