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This is a discussion on Front end within the General forums, part of the Caferacer.net Forums category; I have an interesting question. A friend of mine who is rebuilding a R75 BMW into an awesome steet bike showed me a neat trick. ...

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Thread: Front end

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    Senior Member Pete Casper's Avatar
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    Front end

    I have an interesting question. A friend of mine who is rebuilding a R75 BMW into an awesome steet bike showed me a neat trick. He put a spare lower triple tree fork brace (with stem and excess metal shaved off) on about halfway between the working lower triple tree bracket and the fender bracket/brace. I thought this was a neat idea to really make the front end tight and reduce flex. He swears that it works and I believe him. Anyone ever try this on their CB350 or is it just not needed if you have a good fender bracket/fork brace?

    Pete

    Yeller'
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    FR
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    quote:
    I have an interesting question. A friend of mine who is rebuilding a R75 BMW into an awesome steet bike showed me a neat trick. He put a spare lower triple tree fork brace (with stem and excess metal shaved off) on about halfway between the working lower triple tree bracket and the fender bracket/brace. I thought this was a neat idea to really make the front end tight and reduce flex. He swears that it works and I believe him. Anyone ever try this on their CB350 or is it just not needed if you have a good fender bracket/fork brace?

    Pete
    If I understand this, it sounds like the new brace is attached to the fork legs, not the sliders. If that's the case, I hope he's figured out how to limit the fork travel internally, 'cause it's gonna be "interesting" to say the least, when the front wheel or fender comes up into that thing. It'll be tight alright...but something's gonna flex.


    FR


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    Senior Member champ's Avatar
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    Pete

    I'm not an expert but I would think that would make the front to stiff. The font end is designed to flex and if it's to stiff it it will probably brake something.

    JS

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    Senior Member Geeto67's Avatar
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    Basically what he built was a tweak bar. Tweak bars are what chopper guys in the 70's use to keep their extended front ends from flexing.

    Does it work? well some of the larger 70's superbike racers used to use extenders to the triple clamp to keep their front ends from flexing (you see this most on kz900s and kz1000s) during cornering so there is some thing to it. basically you are giving the bike the rigidity of a really short front end without changing rake or trail, meaning the tubes are less likely to flex and when they do they flex in unison. However it does not work as well as well as a real foke brace which attaches to the sliders since the sliders are the more dynamic part of the front end. In addition a tweak bar can have the effect of causing the sliders to flex out of alignment more since they are now having to absorb more of the cornering flex.

    Personally I think on a street bike a tweak bar is useless, or worth less than a real slider brace because road surfaces tend to be rougher than track surfaces and that extra flex give you a little extra suspension effect. On a race bike it would make more sense because it would be used in conjunction with a slider brace. Your friend made his out of an old bottom clamp which to me is a heavy lump of shit. In my opinion it sounds like it is more weight than it is worth.


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    LiLBull's Avatar
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    old addage what works on a race machine doesnt always work on the street.Two different enviroments.so alot of things that work on the track dont work on the street.like cams alot of newbies throw in cams in their cars and bikes with out understanding its a comprimise in sacrifice.A cam that works on high end will kill the bottom end ,and vise versa.The factory does do its home work on road machines and everything from suspension to cams are chosen for a WIDE RANGE of conditions .A race bike or race car has two things A narrow and well defined enviroment and engineering choices for its enviroment only (a very narrow range).
    Once you start changing and up grading for performance you are making compromised sacrifices ,giving up one one end of the spectrum to gain another end of the spectrum to your own tastes.

    Im so far behind ,that I think Im in first.

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    Senior Member Pete Casper's Avatar
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    thanks for the response folks. I was just interested in varing views. The folk braces are no wheres near the sliders, but I thought of that as well.

    Yeller'
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    Ask not what the wanker can do for you, but what you can do for your wanker!

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    Senior Member JAM614's Avatar
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    I have acquired some triple trees to do the same mod on my R50, R75 and possible the cb350.
    If you look carefully at the CC Products Junkyard Dog this has been done ( For those that doen't know, this bike kicked butt for years on the national level in Formula 750);

    Just use some zipties on top of the sliders to find max travel on the tubes and then go a little beyond to prevent bottoming.

    Jeff


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    LiLBull's Avatar
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    wish that picture was bigger ,my cyber eyes can see closer .

    Im so far behind ,that I think Im in first.

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    Senior Member JAM614's Avatar
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    For a bigger pic of the "Dog" go here;
    http://www.flickr.com/photos/[email protected]/104010663/




  11. #10
    Senior Member Pete Casper's Avatar
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    JAM - From one airhead nut to another...nice ride!

    Yeller'
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    Ask not what the wanker can do for you, but what you can do for your wanker!

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