Newbie Tech questions
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Thread: Newbie Tech questions

  1. #1

    Newbie Tech questions

    I recently bought a used bike ( 1989 kawi zx750 ). It comes with a after market exaust. I'm not sure whether its a slip on or whatever.
    see for yourself.

    anyway the thing is really loud and i don't think it passes air care. It's so bad that after having the bike on in the garage for like 10 mins a strong smell of exaust fume is stuck on your clothes and totally wants to make you puke.

    my question is what should i do to make the bike quiet and aircare friendly again? If i have to change the whole thing i think i might just go undertail exaust system.

    i know a newbie shouldn't be riding a 750 but im not rich so its one bike only. no money for a smaller one then a bigger one then a newer one. i also i got this for cheap. the gear alone robbed me blind.

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  3. #2
    Registered User Array
    Join Date
    May 2002
    West Vancouver
    '79 Honda 500SE<- Joke, I have a nice bike
    Unless I have missed out on something in the last couple months, aircare isn't an issue for bikes. If you are worried about the environment, you need to get a different bike. A 1989 Kawi is a smogpusher to begin with. It didn't even have a cat converter if I remember correctly.

    As for the loud part, I wouldn't worry until you get a ticket. There are many extremely loud bikes. Now if you just want to be a good person you are probably stuck paying for a stock exaust. Pretty much every aftermarket pipe/system is louder than it's stock equivelant, unless someone out there can suggest another option. I have seen some products for reducing the noise of dirtbikes that didn't interfere with the exaust flow, but I have never heard of anyone putting them on a streetbike.

    Don't worry about riding that 750. It's less powerfull and twitchy than most of the new 600 sportbikes anyway. If you can handle the extra weight then you'll be as safe on it as you would on a 600.


  4. #3
    Registered User Array
    Join Date
    Aug 2003
    Greater Vancouver
    Yeah, no aircare for bikes. Your exhaust looks like a supertrap brand exhaust. There's a series of plates at the end of the exhaust, and you can make it quieter by removing a couple of these. Doesn't make a big difference though. Sometimes old pipes can be repacked with new insulation which will make them quiter (they get louder over time as the insulation wear out), but I'm not sure if supertrap's work that way? Some other aftermarket pipes may be quieter, but I don't know how you'd tell without trying one. If you can find a used stock system that may be an option.

    As for running it in your garage producing toxic fumes: don't run it in your garage! Once it's warmed up it shouldn't produce black smoke or anything out of the exhaust, but if it does while it's warming up and the choke's on I wouldn't worry about it. You'll probably have to ride it to get it properly warmed up.

  5. #4
    Addicted to two wheels Array rscudiver's Avatar
    Join Date
    Jun 2003
    Kawasaki ZRX1200R
    Air care is only for the 4 wheel motorcycles. That is NOT a slip on!

  6. #5
    Moderator Array TeeTee's Avatar
    Join Date
    Feb 2002
    Out to pasture in the 'Wack
    04 Kawi Z1000,
    First off if you run any bike in a closed space the exhaust gas smell is going to stick to you like a cheap tart after she sees you're pay wad. Now if your bike is particularly bad then it may be jetted too rich. Hard to say without looking into it and checking it out.

    That muffler is a tiny little can that isn't much larger in diameter than the pipe leading into it. I seriously doubt it's got much if any packing in it. If there IS a perforated core that normally has some fiberglass packing around it then it's probably way overdue for some packing material to be put in there. Also that is the style of can that has the adjustable stack of noise limiter plates at the rear. Try pulling off the stack to check to see if you can pull out the core and repack with glass fiber and while you're at it take off about 1/3 of the noise discs at the rear.

    Imperial has packs of fiberglass wool that is coarse enough to live a while at $15 a bag. One bag will easily pack that can about 4 times over. Pack in LOTS. Really jam it in there. The firmer you can make the glass packing the lower and more mellow the sound. And then fine tune the noise with the number of end cap discs.

    But I fear that a can that small in diameter is never going to be truly quiet but with new glass wool and some playing it should be tolerable.

    Good luck. And I don't need to tell you to treat that bike with respect. It's a heck of a bike to learn on if you can't hold your ego in check.
    A backyard mechanic without a service manual is just like a hooker without a lamp pole.... they are both in the dark.

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