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Get extra cooling on your bike with black paint.

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    #16
    There is something not right here. I am thinking there is a difference between black metal and metal painted black.
    Believe in truth. To abandon fact is to abandon freedom.

    Nature bats last.

    80 GS850G / 2010 Yamaha Majesty / 81 GS850G

    Claimed by Hurricane Irma 9/11/2017:
    80 GS850G / 2005 Yamaha Majesty / 83 GS1100E / 2000 BMW R1100RT / 2014 Suzuki DL650

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      #17
      You guys are getting way to deep.

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        #18
        Um... Air cooled race motors ARE painted black. Race headers ARE painted black. :-) It really does make a huge difference.
        You'd have to be crazy to be sane in this world -Nero
        If you love it, let it go. If it comes back....... You probably highsided.
        1980 GS550E (I swear it's a 550...)
        1982 GS650E (really, it's a 650)
        1983 GS550ES (42mpg again)
        1996 Yamaha WR250 (No, it's not a 4 stroke.)
        1971 Yamaha LT2 (9 horsepower of FURY.)

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          #19
          Black is Cool....or Hot...depending on which slang you want to use.

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            #20
            Originally posted by Jethro
            Mr. Wizard!! Cool stuff! I'm curious why though if you find the data.

            I love my black engine...
            See. Now you got it figured out\\/ \\/ \\/
            Doug aka crag antler

            83GS1100E, gone
            2000 Kawasaki Concours
            Please wear ATGATT

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              #21
              Originally posted by Rock
              So if I wear a black shirt and pants in the sun I wil stay cooler than wearing light clothing?
              Rock, it depends on the direction. When wearing a tshirt, the sun will radiate towards you more than you radiate away from you. (environment hotter than the object). In an engine, the object is hotter than the environment.

              Since black is a good absorber, bad on a hot day in the sun.
              Yamaha fz1 2007

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                #22
                A couple of things, if someone has a lazer thermometer, some paint and some metal a test can be done. I would have three pieces of metal, one piece should be unpainted, the next should be painted black, and the final one should be painted something like white. Get the bits to room temp, then toss them in an oven for a few minutes, lets say 400F for 10 minutes (or what ever you want). If the hypothosis is acurate then the black metal should be hotter then the white, and hotter then the plain metal. If the plain metal is hotter then the paint is acting as an insolator, and not a conducter of engergy. This is only acurate if the objects are other wise the same, metal, shape, size and weight. A variation in any of these would affect the heating/cooling of the object. I also say look at the heating power instead of the cooling power because its simpler to get the temps all the same at room temp. I suppose you could use the freezer though.

                The second part of this is would a oil cooler or larger cooler be effective in negating any temp increase in the engine?

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                  #23
                  So with this theory my black exhaust should cool better than a chrome one?
                  Currently bikeless
                  '81 GS 1100EX - "Peace, by superior fire power."
                  '06 FZ1000 - "What we are dealing with here, is a COMPLETE lack of respect for the law."

                  I ride, therefore I am.... constantly buying new tires.

                  "Tell me what kind of an accident you are going to have, and I will tell you which helmet to wear." - Harry Hurt

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                    #24
                    Since this is still going:

                    If the metal was black. It would work.

                    But the metal is still shiney, therfore the heat will still reflect of the surface of the metal back towards the engine, preventing the heat from going to the paint, just as much as it would prevent the heat from going to the air. A barrier between metal and paint is still a barrier, just as a barrier between metal and air is. The paint and the metal are not the same, therefore you cannot treat them both the same (if the enginer reflects 70% of the thermal energy inwards, it will still do the same if you put paint on it).

                    This is my theory.

                    Either way, i doubt that there is much of a difference.

                    And as for the black metal of stoves, i believe that has more to do with the carbon content of the iron.

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                      #25
                      Originally posted by gs54
                      You guys are getting way to deep.
                      This is fun! It's not like I have a life anyway:? .

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                        #26
                        Originally posted by Jethro
                        So with this theory my black exhaust should cool better than a chrome one?
                        It does. We both have the same exact exhaust on the same bike with the same engine. Had we thought of it when we took a break we could have checked because the only difference between my chrome exhaust and your chrome exhaust is that mine is silver and yours is black. I guarantee yours cools off quicker than mine.

                        This conversation is funny. You all talking and wondering about something that the bike manufactures knew back in the 80s. This is not new information guys.

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                          #27
                          It's new to me! And interesting. I always knew a dark color absorbed sunlight, but I never knew it affected cooling in anyway.

                          I'm wondering why very few sportbike engines are black these days. And performace car engines. Maybe they have sophisticated enough cooling systems so they don't need to spend money on paint. Still this thread is interesting.
                          Currently bikeless
                          '81 GS 1100EX - "Peace, by superior fire power."
                          '06 FZ1000 - "What we are dealing with here, is a COMPLETE lack of respect for the law."

                          I ride, therefore I am.... constantly buying new tires.

                          "Tell me what kind of an accident you are going to have, and I will tell you which helmet to wear." - Harry Hurt

                          Comment


                            #28
                            Originally posted by Jethro
                            It's new to me! And interesting. I always knew a dark color absorbed sunlight, but I never knew it affected cooling in anyway.

                            I'm wondering why very few sportbike engines are black these days. And performance car engines. Maybe they have sophisticated enough cooling systems so they don't need to spend money on paint. Still this thread is interesting.
                            I think it is more how you think of it. The black isn't so much affecting cooling or heating as much as it is affecting heat transfer. It transfers temperature well so if the item is cooler than it's surroundings it will take heat faster from that environment while if the black item is hotter than its surroundings then it will expel the heat into its environment faster. I am guessing that the improvement gained by this is marginal. If it were a really big difference this would be better known and would be a mandatory modification by most manufacturers.

                            My last comment was only based on the fact that when I was 16 (1983) I asked the sales guy at the Yamaha dealer who was selling me my then brand new 650 turbo that came complete with black chrome pipes and black engine, why in the world they would paint it black when "black attracts heat doesn't it?" This that I said in the last paragraph was the reply I got to that. Maybe this isn't as widely known as I thought it would be but it certainly is not new. Just maybe not as widely published.

                            I do know that my black pipes always cooled off way faster than silver chrome pipes did. That much I have seen myself.

                            Most modern sport bike engines are black are they not? I actually haven't noticed but my minds eye is telling me yes?
                            Last edited by Guest; 08-04-2006, 01:57 PM.

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                              #29
                              Some info on the subject:

                              http://www.sacskyranch.com/paint.htm

                              I suspect that parts painted black may appear to cool off quicker because the paint is either polymer or ceramic based. Either of these have significantly lower thermal capacities than metal (aka insulaters). This would cause the painted parts to appear cooler (as the plastic handle on a pot appears to cool down faster than the pot itself, once it is removed from the oven).
                              Last edited by Guest; 08-04-2006, 04:22 PM.

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                                #30
                                Originally posted by jm_foote
                                This does not however, change the fact that a black engine looks really cool!!
                                Amen. I wasn't pondering radiation or convection when I put the flat black to my old 850's motor. Goes great with yellow.
                                Believe in truth. To abandon fact is to abandon freedom.

                                Nature bats last.

                                80 GS850G / 2010 Yamaha Majesty / 81 GS850G

                                Claimed by Hurricane Irma 9/11/2017:
                                80 GS850G / 2005 Yamaha Majesty / 83 GS1100E / 2000 BMW R1100RT / 2014 Suzuki DL650

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