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Engine fires but won't start

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    Engine fires but won't start

    I recently started bringing my hawk out of deep storage and have encountered a problem when trying to start the bike. The engine will fire with the enrichment lever engaged for a couple of revs but won't stay running (I did get it to start for a few minutes one time, but haven't had any luck since). I rebuilt the carbs via the tutorial I found on the site, put new gas in the tank and everything seems to be right, but clearly something is amiss. Without the enrichment, it will turn over with no signs of starting. The plugs have spark and gas is going into the carbs (i have tried draining the bowls a few times) and it did start that one time and idled for a few minutes after a short warm-up.

    Anyway, I am stuck. Any suggestions would be appreciated.

    #2
    It sounds like you're describing a lean pilot circuit. Got any other pilot jets?

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      #3
      Yes, I have a stage 3 factorypro kit installed with pods. I thought I had it set up correctly the last time I rode it but I will try some bigger jets.

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        #4
        Lean it would still idle. Stock idle jets idle just fine even on big modded motors. If you have other slow jets swapping them out may help, but the size of the slows you have in there is very likely not the issue.

        Somthing is clogged/wrong somewhere.

        Where you able to get a wire through the jet? Is the fuel pump working? How about the intake boots, are you sure you are seated in them and that they are not letting a bunch of air in?
        Don't spend money and buy, spend time and learn.

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          #5
          I am going to pull the carbs and double check everything. Fuel pump is definitely working.

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            #6
            Sounds like clogged pilots to me.

            If you're already cleaned your carbs. Clean them 3 more times.

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              #7
              Originally Posted by Yoshihns View Post
              Sounds like clogged pilots to me.

              If you're already cleaned your carbs. Clean them 3 more times.
              but he claimed he rebuilt his carbs, so you're sayin he diddn doa good job ?
              "It's only getting worse."


              MY rides: '97 VFR750, '90 Red Hawk, '88 Blue/Black Hawk, '86 RWB VFR700 (3), '86 Yamaha Radian, '90 VTR250, '89 VTR250 (2), '73 CB125, '66 Yamaha YL-1

              Sold: '86 FJ1200, '92 ZX-7, '90 Radian, '73 CB750, '89 all-white Hawk, '88 blue Hawk, '86 FZ600, '86 Yam Fazer 700 , '89 VTR250, '87 VFR700F2, '86 VFR700F.

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                #8
                I think the floats are set wrong. If the fuel level is too low, it won't get picked up by the jets. Or the mixture screws are too lean.
                Eric Y.
                NT663/VFR800/CBR600F4i
                Yuzon Designworks

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                  #9
                  Carbs are off but no time to look at them yet. Pretty sure the floats are set right although I will check those as well once I get them apart. I'm guessing there is something clogging the jets that I missed when I was in there before. Thanks for all of the input!

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                    #10
                    don't forget to make sure the screens above the float valves are clean too.
                    Brian - Richland, WA
                    1991 Hawk GT
                    1997 VFR

                    Comment


                      #11
                      post-3647-0-85981000-1347898810.jpg
                      "It's only getting worse."


                      MY rides: '97 VFR750, '90 Red Hawk, '88 Blue/Black Hawk, '86 RWB VFR700 (3), '86 Yamaha Radian, '90 VTR250, '89 VTR250 (2), '73 CB125, '66 Yamaha YL-1

                      Sold: '86 FJ1200, '92 ZX-7, '90 Radian, '73 CB750, '89 all-white Hawk, '88 blue Hawk, '86 FZ600, '86 Yam Fazer 700 , '89 VTR250, '87 VFR700F2, '86 VFR700F.

                      Comment


                        #12
                        Originally Posted by squirrelman View Post
                        This ^^^^^^^
                        Don't spend money and buy, spend time and learn.

                        Comment


                          #13
                          Originally Posted by squirrelman View Post

                          but he claimed he rebuilt his carbs, so you're sayin he diddn doa good job ?
                          Carbs are only clean up to the moment they are back on the bike. I've done hundreds of carb cleans. Check to make sure everything is clear and right. Sometimes there's just something in the line or something that'll clog it right back up. Sometimes you just missed something. Just cause you cleaned it once doesn't mean it's still not an issue. Consider it a joke of wisdom.

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                            #14
                            Last year, saw a bike that had been stored a while, the fuel filter was so old it disintegrated and chunks were getting into the carbs. Resolution included swapping out all the fuel lines because they kept passing bits of the filter over time.
                            Flock of Hawks | '13 Tacoma | '69 Falcon (currently getting reassembled!)
                            I've spent most of my money on women, beer, cars and motorcycles. The rest of it I just wasted.

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                              #15
                              I finally had some time and took things apart. There was some old fuel congealed in the jets, so I cleaned that out. My diaphragms look sort of wrinkled, there are no holes but do they need to be replaced? Thanks for all of the replies.
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