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Thread: honda atac???

  1. #1
    Join Date
    Apr 2009
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    Default honda atac???

    started to clean up my bike tonight since she is dirty and grimmy from its long life.. anyways i noticed the atac system on them... i got a little bit of info on it threw searching google..

    but im not understanding it fully.. im guessing its a early power valve system??? since it was replaced by the HHP set up.. Read that some people remove it by installin a aftermarket pipe ( im looking to get a dg national pipe for it) which removes that.. BUT what are the effects of removing the atac in favor of aa/m pipe??

    BTW my bike is a 84 honda cr125r.. stock except for a old school answer s-a pro spark arrestor/ silencer ( was thinkin of putting my powercore2 on it but its stupid loud with the pc2 on it)

    im a bigger guy, 5'11'' 255 so i dont want to do anythingt hat will hurt the little bit of low end it has,
    84 atc 200x msr bars scott grips fast trekker rears durablue spacers moose filter dg exhaust, dropped and ready to slide!

    84 cr125 R.I.P. 1984-2009

    'let those who slide decide'

  2. #2
    Join Date
    Feb 2009
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    new castle pa
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    Default

    It is an early power valves system, which I believe is rod actuated. It opens a butterfuly, giving the bike more low end. There is a way to adjust it, but I am not fully aware of how to do so either. Check with SLIDER, he should know.
    1980 RM250
    Stock, 90% complete, needs restoration, for sale perhaps....

    1988 CR125
    std. bore, FMF fatty pipe, powercore silencer, possibly Eric Gorr 144cc candidate in the future...

  3. #3
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    Default

    +1 for ask SLIDER, hes the know all dirt bike guy.
    03' blaster


  4. #4
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    Default

    Quote Originally Posted by cds00bsmg View Post
    It is an early power valves system, which I believe is rod actuated. It opens a butterfuly, giving the bike more low end. There is a way to adjust it, but I am not fully aware of how to do so either. Check with SLIDER, he should know.
    yeah that much i gathered.. pretty simple set up it seems, works just like a hhp set up.. passes into the can under the chamber than out into the expansion chamber.. than when the butterfly opens it passes straight into the pipe.. giving low throttle power and high rpm power..

    whats gonna happen if i go a/m pipe?? loose a ton of bottom end? i dont mx race and never will so my bike wont spend most of its life in the high revs,

    the national pipe eliminates the atac, so i dont see a pipe maker making something that will have advers effects on the power?? unless it looses low end and picks up a crap ton of top end?
    84 atc 200x msr bars scott grips fast trekker rears durablue spacers moose filter dg exhaust, dropped and ready to slide!

    84 cr125 R.I.P. 1984-2009

    'let those who slide decide'

  5. #5
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    You may lose a bit of bottom, but the gains in the mid and up top will be woth it imo. Also a good pipe will add power all around, my vote is to go with an a/m pipe.
    03' blaster


  6. #6
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    Quote Originally Posted by 2stroker27 View Post
    You may lose a bit of bottom, but the gains in the mid and up top will be woth it imo. Also a good pipe will add power all around, my vote is to go with an a/m pipe.
    looks like DG is the only pipe available for it yet... unless there is something out there besides the dg
    84 atc 200x msr bars scott grips fast trekker rears durablue spacers moose filter dg exhaust, dropped and ready to slide!

    84 cr125 R.I.P. 1984-2009

    'let those who slide decide'

  7. #7

    Default Pipe

    I sent in a bike i bought to get fixed and the old owner took the whole thing apart and lost some parts in the manafold... i donno two much about bikes....but the pice i need is the
    ARM A, ATAC VALVE ... honda stoped making them and its so hard to find....so with this pipe will it illiminate the Manafold ? if you could help me out that would be so great

    Cheers

  8. #8
    Join Date
    Oct 2007
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    Ohio
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    Default

    If you need low end, and going by your size, you would be better off saving all your $, selling the 125 and getting a 250.

    Or, save any money you would modding the 125 to suit your needs, and ride it and save what you can to get a 250. LOTS more low-end power.
    Toys:
    84 250R, 300 kit, Balanced Crank, FLOTEK porting, Wiseco piston,38mm Keihin, Vforce 3, DG type II, UNI Filter
    1980 XL80S
    6.5 HP minibike
    2002 Ranger,Junkyard rebuild
    1969 Broncco TX-6

    Any system that seeks punishment of an individual for "wrongs" committed against noone but the law itself is not interested in peace or equality, but in being able to control and manipulate it's citizens.

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  9. #9
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    Oct 2008
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    Anderson, Indiana
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    The ATAC power valve system was an early attempt by Honda to give the bike some low end pull. It worked okay but was replaced later in 1987 by the spindle style which was integrated into the cylinder and adding a pipe to the bike was a lot easier to work on than the 84-86 ATAC machines.

    If you can find a Pro Circuit pipe for your 84 buy it. It was the best pipe for that machine besides the famed HRC pipe. (that is what I run on my 88)

    Here is a diagram of yours:


    The plunger was built into the exhaust manifold and is total pain in the ass to tune. Some say this exhaust system hurt the Honda when it failed because it choked the machine out quite a bit and it took some time to get it right after you rebuilt the top end. My advice on these is to port out the exhaust exit and dummy up the ATAC totally. Then put a decent pipe on your bike.

    Now on totally removing that exhaust manifold I am not sure what you can find to replace it anymore which is why it might be easier to box up the parts for the ATAC and just make a block off plate and use a good pipe to get your machine dialed in.
    If it ain't broken yet, you ain't tryin' hard 'nuff.