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Hard start issue when hot

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  • Hard start issue when hot

    Hello all, having a bit of an issue with my bike. Have a 90 1100 bone stock with about 54000 on the clock. Have been having a hard start problem for some time when hot. Cold starts fine and runs good. When I take it out for a 20 minute ride or so and shut it down, on restart I have to have the throttle cranked opened or let it crank for a long time for it to start. I can smell fuel and occasionally fuel drips out of the rear tube that connects to the carb I adjusted the valves and found the exhaust and most of the intakes were to tight. Adjusted and bike smoothed out quite a bit but still have the hard start issue. Battery is good, spark plugs are good, not having any bog or real idle issues. I ordered some coils thinking that its a heat soak issue will see if that helps. Also considering the relay coil mod. Any suggestions would be much appreciated!
    1990 1100

  • #2
    Check your oil for fuel.fuel shouldn't drip at anytime.
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    • #3
      Thanks for the reply, I smelled the oil and no fuel smell there. There is a line the runs to the back of the bike and ends above the rear brake caliper, thats connected to the carb. Assuming that is the overflow, it only leaks when I have this hard start issue and continue to crank. Once started there are no leaks and it doesn't leak at any other time.
      Last edited by ranger2003dog; 04-16-2017, 02:44 PM.
      1990 1100

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      • #4
        The only time fuel should come down that hose is when it's on its side. You could be over heating and heat soaking the carbs.
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        • #5
          Originally posted by 92xjunker View Post
          The only time fuel should come down that hose is when it's on its side. You could be over heating and heat soaking the carbs.

          Hmm, maybe a oil cooler restriction?
          1990 1100

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          • #6
            Possible...or running too lean
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            • #7
              Originally posted by 92xjunker View Post
              Possible...or running too lean
              Once shutdown from riding it does seem to be pretty hot. Its never died when idling etc. I have a oem air filter installed, as mentioned bike is stock, oem mufflers etc. I have heard some popping on decel occasionally.
              1990 1100

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              • #8
                Run some fuel system cleaner in the fuel. I use redline rated #2 in effectiveness.
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                • #9
                  Originally posted by 92xjunker View Post
                  Run some fuel system cleaner in the fuel. I use redline rated #2 in effectiveness.
                  Will do, I appreciate the replies! I never thought about a carb heat soak issue but it makes sense as the fuel might be boiling out etc. Can you pickup the red line at a big box store?
                  1990 1100

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                  • #10
                    Not sure on that..
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                    • #11
                      Has anyone else had hard restart issues when hot? Will be pulling the carbs soon to make sure there isnt an issue there. Ran seafoam through since I couldn't find redline and it helped slightly to smooth things out. Still having the problem.
                      1990 1100

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                      • #12
                        If you are pulling the carbs, it would be a good time for a full clean and new o-rings if it hasnt been done since new, 27 years ago.
                        1989 GSXF 750 Katana.
                        V&H supersport exhaust, ported head, GSXR cams
                        Michelin PR2's, RT fork springs and R6 shock

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                        • #13
                          1) You could be hydro-locking (I think thats the correct term)...what I mean is if the gas tank can't breath it creates a vacuum and fuel can't flow.
                          2) I found my timing pickup thingy loose one time. My bike fell over/friend sat on it and dropped it...busted the right side/front cover. I removed the cover to find one screw had backed out about half way from that pickup device. That could cause hard starting/timing issues. However, I seriously doubt thats your problem...just saying.
                          3)If your riding a 1100, the service manual suggest 89 octane. Depending on your sea level, outside temp, and pilot screw settings, that may cause problems. Warning, those screws are a bitch to adjust. I bought a finger bit screw driver with Motion Pros extended bit. http://www.ebay.com/sch/i.html?_from...river&_sacat=0

                          https://www.motionpro.com/search?q=bit
                          EDIT: Take carb cleaner spray and get a friend to hold the throttle wide open. Then spray the insides of the carb bodies really good while lifting the diapragms to clean the needles too. The most important part is that your trying to clear the pilot circuit holes of carbon build up. Be sure to start the bike immediately after to keep the drain off from actually seeping back into the holes. It worked for me

                          EDIT:
                          4) Is your petcock on prime ?
                          Last edited by katanarider; 04-17-2017, 01:36 AM.
                          My Katana-1100 17" wheel swap
                          http://katriders.com/vb/showthread.php?t=136894

                          Comment


                          • #14
                            Originally posted by ZookRick View Post
                            If you are pulling the carbs, it would be a good time for a full clean and new o-rings if it hasnt been done since new, 27 years ago.
                            I actually bought a good used carb set several years ago and went through it before reinstalling them. Also have synced them multiple times since. Last sync and clean was about a year ago. Are the o rings you are talking about for the fuel pipe? I did not replace those last time I had it apart. The fuel dripped has been an issue for quite some time. It drips fuel when having this hard start issue and extended cranks to fire it when hot. I have had it leak a few times on shut down as well, kinda baffled about that. When actually riding the bike there isnt a bog or surge of power at all. The idle sometimes will randomly drop to about 800 rpm and then bounce up. It just has been an issue for so time and seems to be getting worst. Not sure if its electrical or carb related could be something else as well

                            Originally posted by katanarider View Post
                            1) You could be hydro-locking (I think thats the correct term)...what I mean is if the gas tank can't breath it creates a vacuum and fuel can't flow.
                            2) I found my timing pickup thingy loose one time. My bike fell over/friend sat on it and dropped it...busted the right side/front cover. I removed the cover to find one screw had backed out about half way from that pickup device. That could cause hard starting/timing issues. However, I seriously doubt thats your problem...just saying.
                            3)If your riding a 1100, the service manual suggest 89 octane. Depending on your sea level, outside temp, and pilot screw settings, that may cause problems. Warning, those screws are a bitch to adjust. I bought a finger bit screw driver with Motion Pros extended bit. http://www.ebay.com/sch/i.html?_from...river&_sacat=0

                            https://www.motionpro.com/search?q=bit
                            EDIT: Take carb cleaner spray and get a friend to hold the throttle wide open. Then spray the insides of the carb bodies really good while lifting the diapragms to clean the needles too. The most important part is that your trying to clear the pilot circuit holes of carbon build up. Be sure to start the bike immediately after to keep the drain off from actually seeping back into the holes. It worked for me

                            EDIT:
                            4) Is your petcock on prime ?

                            Will try this carb clean method thank you! No the pet cock is in the normal position, 9-3. I have thought about the hydro locking ( vapor lock ) issue may be the problem since I am in phoenix AZ where its ungodly hot. May have to check to see if the vent is working properly
                            Last edited by ranger2003dog; 04-17-2017, 02:41 AM. Reason: Automerged Doublepost
                            1990 1100

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                            • #15
                              If your floats are sticking, you can try Lucas upper cylinder lube mixed with your gas. That may lubricate the floats and needles. Also, your vacuum assist diaphragm on the petcock maybe pulling too hard or stuck open or some thing crazy like that.
                              My Katana-1100 17" wheel swap
                              http://katriders.com/vb/showthread.php?t=136894

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