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Thread: atc 70 project help...motor swap?

  1. #1
    Join Date
    Aug 2010
    Location
    Clinton, TN
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    72

    atc 70 project help...motor swap?

    I might be getting an atc 70 with no motor for cheap. Ive never done a motor swap on anything or had any motor completely out of a bike before so Im gonna need some help from you guys.

    Im wondering if this is a motor that will work for me and also is this everything Ill need? What can I use for some better brakes?
    http://cgi.ebay.com/ebaymotors/LIFAN...item19bfe65621

    thanx

  2. #2
    Join Date
    Aug 2010
    Location
    Clinton, TN
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    72
    anybody???

  3. #3
    Join Date
    Jul 2008
    Location
    MD
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    911
    Your gonna need a kill switch and some sort of throttle. I am not sure if you have the stock 70 parts or if you could even wire then to work.
    Also remember this is a kick start engine and the rear fenders will get in the way unless you do the pull start conversion on it.

  4. #4
    Join Date
    Aug 2010
    Location
    Clinton, TN
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    72
    Ok...Isnt there a site that sells the 70 parts and the whole motor swap kits?

  5. #5
    Join Date
    Jun 2010
    Location
    Nebraska
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    105
    Wish you lived closer, I would GIVE you a 90 engine that runs great and is in my way all the time...

  6. #6
    Join Date
    Jul 2010
    Location
    texas
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    7
    dratv.com sells everything you need, plus has the wiring diagrams. You will want to add the pull starter off of your honda engine because you can't kick start it with stock fenders.

  7. #7
    Mosh is offline I'm the one with all the 2 stroke around here! The day begins with 3WW
    Join Date
    Jun 2005
    Location
    na
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    5,702
    I just put a Pirhana 125 4 speed manual clutch in my 70..
    I am no expert, but I will try to give you some good reading here for some good tips..

    1st of all..Do you want it to be auto clutch or full manual?
    If you want the auto clutch, then a Lifan 125 would be best, but I have heard that the trannies dont hold up well in a auto clutch engine above 110cc.
    I used the 125 Pirhana engine with a clutch, specifically becuase I wanted something that had balls and clutch action, since I have a stock 70 to putt on.
    So you need to make your decision. I would advise nothing bigger than a 125 either way..140 and 160 engines in a 70 chassis will wear you out in minutes. Unless you are a big boy..

    2nd.. Only go with Pirhana, Pitster Pro or Lifan..They seem to have the best durabilty.

    Now as long as you stay with the 125 engine or smaller, they almost bolt right in. You may have to grind about 1/8 inch off your frame at the rear upper motormount for the case to clear the frame..No biggie..Hell a file will work.
    Get the complete set-up with the carb, and electrical..They hook up easy and are tuned right outta the box for the most part. You can even wire your stock thumb throttle killswitch to ground the coil and kill the motor.
    You can use the stock cable, but it has to be modified for the bigger carb..A pain in the butt, for what a proper cable will cost, and be simple I would suggest the proper cable.
    You will have to get a pipe. Either a 70 bigbore pipe from Sterdy, or you can use a cheap pitbike pipe and silencer and tweak the rear tube to clear your fenders. But it has to be done right or you will melt your fenders.

    The 2 biggest problems are these.
    1)The bigger carb will not clear the gas tank..There are many ways around this.
    Some guys notch the intake bolt holes at the head, and rotate the carb to the inner frame rail, then dent the back side of the gas tank so the carb clears.
    Others buy a shorter intake, that allows the carb to clear the tank, and others will cut the intake and reweld it so the carb clears the tank.
    Some guys just adapt a different tank..
    2)The starting..
    You can either push start it...PITA
    Or you can shave your fenders, and widen your axle and use the kickstarter like me...
    Or you can buy a pullstart conversion kit...

    Now here is some links for you...

    This is a large thread of highly modded 70's, that has some great tips on how to make these engines fit..But you have to read the whole thread..They answer alot of questions..
    http://www.3wheelerworld.com/showthr...-70s-In-action!!


    Here is a link to my build, which is still currently under construction, but it is rideable now..
    http://www.3wheelerworld.com/showthr...pdate.-9-23-10

    Now I bought my engine from these guys..But they only deal Piranha engines..But they had it all in stock, great prices and 30 minutes from my house.
    http://stores.wholesale-cycle.com/StoreFront.bok

    Sterdy has a crap ton of parts for the 70 mods, and they are the ones that have the throttle cables you will need..
    http://www.sterdyproducts.com/

    And these guys have some things too. Dr ATV..They have the pullstart kits..
    http://www.dratv.com/newreen.html

    As far as the rear brakes, you either have to figure something custom out and adapt newer stuff, or add some front brakes..
    Someone else can chime in on that.

    It isnt that hard to do this conversion..And it is cheap..
    Sorry for the long post, but it should give you some good ideas and a start point.
    Here is where my long useless list of stuff nobody cares about should go...


    Proudly NOT a member of

    "Team on the Teat"

  8. #8
    Join Date
    Aug 2010
    Location
    Clinton, TN
    --
    72
    Wow Mosh, thanx for all the info. Im hopefully going to get the 70 in the moring. The guy who has it owns a boat repair shop and he put it up on the roof to attract customers but I just cant keep driving by it everyday knowing its just getting rustier(sp?) everyday...lol

  9. #9
    Join Date
    Aug 2010
    Location
    Clinton, TN
    --
    72
    Well guys I picked up the 70 today. Its a 82 model and its in pretty good shape. No motor but I was planning a motor swap anyway. I think Im gonna get the pirahna 125 motor. Thoughts on it? What kind of handle bar setups are you guys running on your modded 70s? Will I need a different top clamp? Also my 70 dosent have foot pegs. Can I just buy stock ones and mount them on the pirahna motor or do they mount to the frame?

    thanx
    Last edited by parker88; 10-14-2010 at 02:16 AM.

  10. #10
    Race Demon is offline At The Back Of The Pack Arm chair racerFirst time rider
    Join Date
    May 2009
    Location
    coshocton
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    245
    Pro Taper crf50 bars or the cheap copies, you can find them on ebay,they fit the stock triple clamps, the stock pegs will work if you put a spacer between the pegs and motor, I use alot of the Pirahna motors and like them.

  11. #11
    Join Date
    Aug 2010
    Location
    Clinton, TN
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    72
    Thanx Race Demon...Will the new pirahna motor come with the bolts I need to mount the motor, cause I dont have them?

  12. #12
    Join Date
    Aug 2010
    Location
    Clinton, TN
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    72
    Heres the pics guys...






    These last two pics just show the main things its missing and the busted up sprocket cover...



  13. #13
    Join Date
    Jan 2010
    Location
    Springfield Mo
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    3,309
    Can't beat free!!! The 125cc will be a great Mod for that. The Lifan will bolt right in with no problems. Check out Mosh's threads above. Great info there.
    Keep on Triking!!!! "I am the NIGHT RIDER!!!"

    RIP Ninja!

    Feedback thread: http://www.3wheelerworld.com/showthr...-for-thestud25

    Trike Fest 2011, 2012 Vet!
    Founding member of the Haspin 6ft Bats Club!!

    Trikes Currently Owned:
    87 Big Red 250es
    86 Kawasak KLT110. All documentation, bought from original owner.
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  14. #14
    Race Demon is offline At The Back Of The Pack Arm chair racerFirst time rider
    Join Date
    May 2009
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    coshocton
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    245
    Quote Originally Posted by parker88 View Post
    Thanx Race Demon...Will the new pirahna motor come with the bolts I need to mount the motor, cause I dont have them?
    no you will have to buy some motor mount bolts, you will also need a clutch cable and clutch lever and perch, you will have some other mods to do once you get that far

  15. #15
    Join Date
    Aug 2010
    Location
    Clinton, TN
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    72
    what kind of chain and sprocket setup are you guys running with the 125 motors?
    I dont have any of the stock wires or anything from the 70 motor. My 70 is just a roller. Is there anything from the pitbike motors that is supposed to hook up to any of the old wiring or anything?
    Last edited by parker88; 10-15-2010 at 08:26 PM.

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