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    4 into 4 exhaust?

    Hi, thinking of trying something dumb and could use some advice and/or discouragement.

    I noticed for the first time the other day that the exhaust on my 79 gs850 was pretty leaky around all the joints where the tailpipes slip over the headers. That wasn't too big of a concern to me really as it has been running and riding very well(in my opinion), but another thing that DOES bother me is that at one time somebody did a botch job of cutting my pipes back a little and then also POUNDED some kind of homemade looking baffles in. Really gnarly looking, all rusty and dented. But to their credit, they seemed to work decently, if not sound the best(bike was $400, I ain't about to complain).
    So I got a bug up my arse today and tore the whole works off, with the intention of knocking out the baffles and then researching what kind of aftermarket ones were out there that might work and while I was at it using some 2000°F caulk that left work with me to seal up the joints better.

    Of course the tail pipes are tapered, which makes finding a baffle difficult, and I had to severely abuse them to separate them from the headers. Looks like they were maybe squished slightly in a vise, apparently somebody thought they might come apart somehow while riding. I don't get it. Oh, and those baffles were sure enough at the end of their life. First couple jabs I took at one with a 24" extension went right through.

    Anyways I got to thinking about what to do without spending TOO much money, and I hit on the idea of keeping the original headers and extending each one out with a piece of 1.5" 14gauge stainless pipe and securing a baffle in each one then painting the whole thing with ACE brand 1000°F BBQ Black flat paint. Still probably cost between $150 and $200, but it's something to do and I'd be real curious to see how it sounds.

    Question is; What are the odds that I will never be able to get this thing to run right at all? AND I've also read about how cutting out the crossover pipe can hurt low end power. This bike never had a crossover(to my knowledge), but will dividing the pipes in the manner I'm proposing have a similar effect?

    I've got it pretty well worked out in my head and on paper exactly how I would go about building and securing this exhaust, just wondering if better heads than mine can tell me why I shouldn't.

    #2
    No extra power, but definitely extra weight.
    "Thought he, it is a wicked world in all meridians; I'll die a pagan."
    ~Herman Melville

    2016 1200 Superlow
    1982 CB900f

    Comment


      #3
      Probably easier, cheaper and better just to get a pair of these:



      Current:
      Z1300A5 Locomotive (swapped my Intruder for it), GS450 Cafe Project (might never finish it....), XT500 Commuter (I know - it's a Yamaha )

      Past:
      VL1500 Intruder (swapped for Z1300), ZX9R Streetfighter (lets face it - too fast....), 1984 GSX750EF, 1984 GSX1100EF (AKA GS1150)
      And a bunch of other crap Yamahas....

      Comment


        #4
        The sound of a 4-into-4 would be a bit more "chatter", much like the Honda CB750K. Some might like it, others ... not.

        As far as jetting, you will be pretty much on your own, in uncharted territory. I have not heard of anyone trying that before.

        I installed a pair of the mufflers that hillsy showed on my son's 450. Not quite as quiet as stock, but far from 'loud'. Thinking back, it's sort of like the difference between G or E pipes and L pipes.

        You are correct, the '79 850 did not have a crossover pipe. I have replaced a rusted-out crossover on at least four 850s so far, with no noteable difference in power. The sound is ever-so-slightly different, but you have to know what to listen for to notice.

        .
        sigpic
        mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
        hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
        #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
        #2 son: 1980 GS1000G
        Family Portrait
        Siblings and Spouses
        Mom's first ride
        Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
        (Click on my username in the upper-left corner for e-mail info.)

        Comment


          #5
          Originally posted by dad is retired View Post
          Question is; What are the odds that I will never be able to get this thing to run right at all?
          If you are keeping the stock airbox and filter arrangement then jetting for a tweaked exhaust isn't going to be very hard at all.


          Originally posted by hillsy View Post
          Probably easier, cheaper and better just to get a pair of these:

          http://www.ebay.com/itm/UNIVERSAL-CH...FUfdjh&vxp=mtr
          I would say that would be an excellent solution for OP and the price is very reasonable.


          Mark
          1982 GS1100E
          1998 ZX-6R
          2005 KTM 450EXC

          Comment


            #6
            Interesting, I didn't know the pre 80 bike didn't have a crossover. Guess I've never looked under my part bike to see. Although My parts bike was made in 79 so I don't know if that means it's an 80 model or a 79 model.

            Comment


              #7
              I'm running '79 exhaust system (no crossover) on my '80. No issues whatsoever

              Comment


                #8
                Originally posted by GSinNH View Post
                Interesting, I didn't know the pre 80 bike didn't have a crossover. Guess I've never looked under my part bike to see.
                Although My parts bike was made in 79 so I don't know if that means it's an 80 model or a 79 model.
                How complete is your parts bike?

                There are several differences that are easy to spot, if you know where to look.

                1979:
                chrome front fender
                VM carbs
                "choke" lever is on carbs
                points ignition
                kick starter
                separate rectifier and regulator
                12-pole stator
                headlight switch probably works
                side cover badge says "GS850"

                1980:
                painted front fender
                CV-type carbs
                "choke" is a knob in the steering stem
                electronic ignition
                NO kick starter
                integrated R/R
                18-pole stator
                headlight switch probably still there, but disabled
                side cover badge says "GS850G"

                There are more, but most of these are easy to see (except the stator).

                You can also look for the actual production date on the steering stem.
                Anything after 8/79 might be for the 1980 production run.

                .
                Last edited by Steve; 06-17-2016, 02:04 PM.
                sigpic
                mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
                hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
                #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
                #2 son: 1980 GS1000G
                Family Portrait
                Siblings and Spouses
                Mom's first ride
                Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
                (Click on my username in the upper-left corner for e-mail info.)

                Comment


                  #9
                  Think I'm scrapping this idea for now. I'd like to be able to ride on fathers day and I can't get any kind of baffles that will work without ordering them. Think the kickstand might need to be tweeked ever so slightly too. Center stand not an issue, for all I know that got taken off thirty years ago and is on someones bike who is reading this. Beautifying the original exhaust as we speak then off to ACE to buy some stuff to attempt a DIY baffle of my own. Actually I'm glad I'm doing this, always thought I could use a tad more restriction, bike pops pretty good occasionally during deceleration. Maybe restriction is the problem, maybe not, but I get psyched about fabricating anything so trying this first. I'll post some before and after pics if it turns out well. If not you will not hear from me again on this topic.

                  Comment


                    #10
                    that's interesting, as my bike is indeed a '79 and the choke knob is up by the handlebars BUT it has VM carbs. Who knows what has been swapped around with bikes this old though.

                    Comment


                      #11
                      Originally posted by dad is retired View Post
                      that's interesting, as my bike is indeed a '79 and the choke knob is up by the handlebars BUT it has VM carbs. Who knows what has been swapped around with bikes this old though.
                      Mine was built 11/79 and has (or had) all the parts for an '80. But when I was into the wiring during the first resto-mod, it seemed to be some kind of mix between the two years, according to the diagrams.

                      It wouldn't be a surprise to see a mix of some parts during model year changeovers, even when they were new. And yes, now you add in 35+ years of owners' repairs and modifications.......

                      Comment


                        #12
                        Originally posted by 850GT_Rider View Post
                        Mine was built 11/79 and has (or had) all the parts for an '80. ...
                        Considering that the '80 production started in August, that sounds correct.

                        .
                        sigpic
                        mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
                        hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
                        #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
                        #2 son: 1980 GS1000G
                        Family Portrait
                        Siblings and Spouses
                        Mom's first ride
                        Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
                        (Click on my username in the upper-left corner for e-mail info.)

                        Comment

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