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  • #21
    Their Main jet suggestions are a bit screwy as well.
    A CV Carb, and they have a huge step due to elevation.
    A stock carb has a 165 Main, and their stepping down to a 160, when a stock 165 is already lean with pipes and intake upgrades.
    Even a bone stock carb at WOT, will flow more fuel then the 160 with more elevation on the needle.

    On top of a 50 Pilot, they have the Tech backing the PMS(idle mixture screw) out 3 1/2. They also also refer to it as a Pilot air screw, when it adjust fuel. Interesting.

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    • #22
      Thank you thank you, I am learning alot, that is why this forum is so awesome.
      Life is tough, it's even tougher if your stupid----John Wayne

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      • #23
        There’s nothing wrong with the Speedstar kit, just remember it won’t use the same jetting recommendations as those normally recommended for a Barons kit.

        Just my $.02. I’d use a 37.5 Mikuni Pilot. A 172.5 Mikuni Main. 4 or 4 1/2 on the needle.

        I’m just tossing this out, based on davej’s experience with a 1700, and how the jetting changes go with the Barons kits for the 1600 and 1700 motors.

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        • #24
          I also say Barons kit. There is a known once and done jetting and no fooling around with it again.

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          • #25
            Thank you, the jet kits should be here by the time I return. Going to be out for a few days.
            Life is tough, it's even tougher if your stupid----John Wayne

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            • #26
              Mike,
              Checking my carb settings and the Yamaha 1600 service manual, the stock pilot jet should be a # 35 for the non California models. I'm not sure what the Calif. models use. I'm running the stock pilot jet #35, 65 main jet, and the needle set on the 3rd clip. The PMS screw is turned out 2 1/4 turns. My profile shows the pilot jet as #27 but it's the stock # 35.
              I did drill the slide, (2 vacuum holes) to 7/64" for quicker throttle response and reamed the bottom 4 holes out .001" on the emulsion tube. Running pumpless w/3mm float valve.
              I am running the Speedstar pistons and heads, aluminum intake, open air box, and Hard Krome 2 into 1 pipes. Spark plugs are indexed and gaps opened to .038". My elevation is 5200'.

              I'm a true believer for the 40mm CV carburetor, and the reason I say this, is my other 1600 RS is set up just alike, but has a HSR 42mm slide carburetor w/TPS on it. It does run well, about the same, but altitude really affects the out put and the best fuel mileage I've had was 38 mpg, where the CV carb wins hands down. I'm getting over 50 mpg if I keep it under 75 and not hot rodding around. With the slide modification on the vacuum holes, I could not feel any difference in acceleration between both carbs.
              I'm just letting you know what I have found out and what has worked with my bikes.
              Duke.

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              • #27
                Duke, The stock jetting for all 1600's is 35 pilot and 165 main jet not 65. The stock non adjustable needle clip position is at the same spot equal to the 4th groove in a barons and speedstar needle. If You are running a 165 main and 35 pilot jet you are running on stock jet size and if on the 3rd groove on the needle you are also running leaner than stock. I understand that the CV carb will tolerate/compensate for altitude change for the "most part" but at altitude you can also tolerate a little leaner jetting than the rest of us with less or no ill effect. You will also get a little better MPG up there. I also believe the CV carb is a great carb. I also drill the slides for better throttle response. The jetting configuration that most of us have gone to is going up in size on the pilot jet. It works great and it was not discovered by accident and old school guessing by butt dyno. I did a few actual dynos at the dealership to compare jetting changes along with exhaust changes to compare the AFR numbers in relationship to HP & TQ readings. Then I purchased a bike mounted AFR meter to tweak my readings for optimum performance with live real time AFR readings. I have jetted somewhere around 50-60 Roadstar carbs maybe even more, they all get a larger pilot and perform better than with the stock pilot jet. Here is a pic of the live real time AFR gauge. I'm not guessing as to what jetting works best.

                Comment


                • hotrod460
                  hotrod460 commented
                  Editing a comment
                  love to know where you got that AFR gauge ????

              • #28
                Dave, I'm not saying you are guessing with the jet sizing, and I'm not guessing either. The stock main jet size for our 1600 is a 160, manual says #60. With the mods on my bike and carb, I had to go up 2 sizes (165) to dial it in. No, I haven't had access to a dyno, but using a stop watch and highway markers works fairly well. You say old school, and I say poor boy. I do know how to read spark plugs and yes you could say old school but some of that works as well.
                I use to build dirt track V-8 race engines and used a dyno to help break in the engines, as well as dialing in the timing and carburetors. Haven't done 50 or 60, but have done at least 14 engines.
                I know several bikers that had only changed out the pipes and didn't have to change the jetting, but when changing the air box to a more free breathing box, jet changes were needed.
                I'm not saying you are wrong, I'm just thinking your telling me that I am.

                I'm' just letting Mike know what works on my bike. I give him the numbers, my elevation, and this info for reference for him to work with, not telling him what to do.

                Thank you for your response. Duke.

                Comment


                • Duke
                  Duke commented
                  Editing a comment
                  SORRY Dave, my manual does say main jet is 165. The first time I went into my carb, it was a 160 according to my records. Have you ever herd of dealers changing jets on new bikes? Duke

              • #29
                Actually, the stock 1600 Main for the CV Carb, is a Mikuni 165. Always has been.

                Comment


                • Duke
                  Duke commented
                  Editing a comment
                  I bought it new in Rock Springs, Wyoming, 2001. The carb had a 160 main jet in it from the factory. Manual says # 60.
                  Purchase 2 carbs for that bike off eBay both having 160 main jets.

              • #30
                Been on this forum for 6 plus years and 100’s of people looking for jetting info. The Old forum had been up and running for close to 15 years, with pages of jetting info. Your comment about your stock main being a 160, is a first.

                Just saying.

                Comment


                • Duke
                  Duke commented
                  Editing a comment
                  I don't know why my bike and the carbs I purchased would have the 160 in them if they shouldn't be? I know for a fact that my bike came with a 160 main jet. The dealer took it out of the shipping crate that way. I had to wait a day to pick it up for assembly and service. Just checked Yamaha parts and they do show a 165 jet. I'm baffled!!!!
                  Last edited by Duke; 6 days ago. Reason: Just checking Yamaha parts and found that interesting news

              • #31
                Hi guys , just to add to this conversation,,,,,,,, first of all im in UK and have a standard needle with 5 grooves,,,,,,,,,,im running primary 37.5,,,,main 180 and clip on 4th groove with spacer and one washer, PMS at 1.5 turns,,(aftermarket thumb screw type, has smaller tip),,,im at 167ft with open pipes and S&S teardrop filter.

                This works for me, ive been working on it for a while, and any smaller main runs a little flat at WOT, rest of the throttle band works fine, no problems to date. plugs read ok and pulls hard all the way

                Im not saying this is right or wrong but it works for my bike and my riding style
                Sometimes it takes a whole tank of gas before i can think straight

                Comment


                • SKWEARpeg
                  SKWEARpeg commented
                  Editing a comment
                  If the 180 is a Mikuni, then that bears out my thinking on the Speedstar needle allowing for a fatter Main.
                  The Wildstars came from the factory, with a multigroove needle, and I’d imagine the profile would be more like a Speedstar, then the slimmer faster tapered Barons or DJ.

                • hotrod460
                  hotrod460 commented
                  Editing a comment
                  Yea i guess that too, after reading all about the jetting with baron and dynajet, it was just not working for me,,, then the penny dropped,,,ive got a uk standard needle, so, start from the pms/primary and work up, and it seemed to work.,,,,,yes all mikuni jets

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