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  • Bike runs fine, then wants to die, then fine again

    Hi all. It's been a while since I last posted... truth be told, I'm considering getting rid of the bike since I don't have the room to store it, the money to put into fixing it up/keeping it licensed/doing required maintenance, or the interest in giving this amazing machine the attention it deserves. Anyway, on to the meat and potatoes...

    Two years ago the bike started running like **** out of the blue toward the end of the season and left me stranded at a grocery store when I couldn't get it restarted. Eventually I managed to get the thing running again but after a few minutes on the road I had to keep the throttle cranked so it wouldn't die. I dumped some Seafoam into the tank and garaged it at my brother's place with the intent to work on it "next year". Obviously that never happened. I have FINALLY found the time to work on it a week ago when a friend wanted to see me fire the thing up. He even bought me a few gallons of premium no ethanol gas and a can of Seafoam!

    I verified strong spark on all four plugs and dunked them in Seafoam to clean off a bit of residue, dried and replaced them, then prayed to the two-wheeled gods. Much to my surprise it started right up once I charged the battery. Warmed up without a hitch, and after I cranked the throttle a few times to see if it was going to mysteriously start sputtering again (it didn't) I decided to put a couple miles on it. Sure enough, halfway through the ride it started coughing and died at a stop. Restarted fine, but I had to keep the throttle cranked to keep it running; even at 3/4 throttle it wouldn't go above 2200 RPM and kept popping as if the mixture was too rich or a plug wasn't firing. Honestly I'm not a mechanic - just mechanically inclined - so I'm kind of grasping at straws here.

    A few hundred feet from my destination it began running great of course, and my buddy thought I was bull****ting when I told him there was a problem. After a few minutes of idling in the driveway the bike started sputtering again. I stuck it in the garage and decided to consult the forums, and that brings us up to present.

    I did a bit of searching and a small break in the pickup coil wire seems like a likely cause given the intermittent nature of the problem. When I go to my brother's place next week with my friend who's more familiar with motorcycles than I am the pickup coil wire is the first thing we're going to check out. I was wondering if anyone had insights as to what else I should look into - and ideally some simple diagnostic procedures - in the event that the coil wire isn't the cause. We already did a "wiggle test" to verify it isn't the spark plug wires. My friend suggested a vacuum leak or a funky air filter, but it seems to me like those would cause consistent problems, not a come-and-go gremlin.

  • #2
    OK, you didn't post what year the XS is, and if it is still running the same year carbs. Yes, that would be my thought, a fuel feed problem.
    #1, try a run with the gas cap loose, not locked down. If it runs great, the vent is probably plugged.
    #2, check all 4 plugs as soon as it starts to run like cr@p, and see if on one or two are black. IF they are, what two makes a difference. From the left, 1&2, 3&4 are paired with the fuel/vents in the carbs. 1&4, 2&3 are paired with the coils, and pickup wires.
    After these checks, let us know what you find.
    Ray Matteis
    KE6NHG
    XS1100 E '78 (winter project)
    XS1100 SF Bob Jones worked on it!

    Comment


    • #3
      Hey New and Ray,

      His bike is an 81 SH. SO unless he's done some modding, then it probably still has the Octopus. That vacuum controlled fuel valve can both stick as well as the vac. line to it can leak....both can cause it to not supply enough fuel, and so after running a little while you can run the bowls a bit low which can also make it feel like it's running on 2 cylinders. SO...to test it being the problem...BYPASS it by putting the petcocks on PRIME....ride it and see if it acts up. Then put it back on ON, ride it and if it begins to act up, switch it to Prime and see if it behaves properly again....if so...then you've confirmed the Octopus has problems. What you do with it is your choice...some get rebuild kits, others just rip it out and remember to turn off the petcocks to prevent accidental flooding IF the carb float valves fail.

      The pickup coil wires don't fail/break any where as often with the later models as the earlier models, but it can happen, so not a bad idea to rule out.

      T.C.
      T. C. Gresham
      81SH "Godzilla" . . .1179cc super-rat.
      79SF "The Teacher" . . .basket case!
      History shows again and again,
      How nature points out the folly of men!

      Comment


      • #4
        T.C. I didn't know what model he had... After all the work I've put into the Quail bike, I tend to focus on the standard. As much as I try to help Ed, you would think I'd keep the Octy in mind, but as my mind is like a sieve now, I guess not.
        The Octy, with a leaky vacuum hose, would make sense.
        Ray Matteis
        KE6NHG
        XS1100 E '78 (winter project)
        XS1100 SF Bob Jones worked on it!

        Comment


        • #5
          Hey Ray,

          I wasn't busting your chops...I'm the least qualified to do that anyways!
          I just looked at his profile, fortunately he had the info there just not in his signature. I just can't recall ever hearing anyone with the 81 year bike that had the PU coil wire failure.....78-80 yes, but not 81....but then again my memory isn't as strong as it used to be either....join the club!

          T.C.
          T. C. Gresham
          81SH "Godzilla" . . .1179cc super-rat.
          79SF "The Teacher" . . .basket case!
          History shows again and again,
          How nature points out the folly of men!

          Comment


          • #6
            Originally posted by TopCatGr58 View Post
            I just can't recall ever hearing anyone with the 81 year bike that had the PU coil wire failure.....78-80 yes, but not 81....but then again my memory isn't as strong as it used to be either....join the club!

            T.C.
            Brant/Motoman did on his '81 Venturer. I was at his house and he asked me to listen to the engine so he fired it up and I told him it sounded like the pick-up coil wires were bad. They were.

            He swore up and down it couldn't happen to an '81 but has the rotating Vacuum Advance plate like every other XS11, it just doesn't have the Mechanical Advance because Yamaha was only half way from ditching the moving parts and learning how to use electrickery.

            .
            -- Scott
            _____

            2004 ST1300A: No name... yet
            1982 XJ1100J: "Baby" SS Brakes, '850 FD, ACCT
            1980 XS1100G: "Columbo" SS Brakes, '850 FD, ACCT
            1979 XS1100SF: "Bush" W.I.P.
            1979 XS1100F: parts
            2018 Heritage Softail Classic 117 FLHCS SE: "Nanuk" It's DEAD, it's not just resting. It is an EX cycle.

            Comment


            • #7
              Just a reply here, not really an update... haven't gotten a chance to work on it yet...

              I have always had the petcocks on RES. On all my bikes going back to 2005. Even when I park and store them (I just put a catch pan underneath so as not to drip on pavement). I keep the tank as full as possible and am a member of the Church of Seafoam - either that or Lucas is always in the fuel. This has never failed me and so long as the battery has good charge my bikes have always fired right up.

              The reason for this is that I Ran into a problem with my old Virago and got stranded due to petcock failure which I attributed to age and overuse. If I should still try the "ride it on PRIME" troubleshooting method I will - gotta be honest in that I only have a basic understanding of fuel delivery from a 2 cycle engine perspective and don't quite get how a vacuum system comes into play.

              As an aside, I would like to thank you guys for helping here. I know how frustrating it can be to advise people with limited topic familiarity (I do computer tech support, mostly for elderly clients) and appreciate your patience. Hopefully my detailed messages are more helpful than aggravating.

              Comment


              • #8
                Don't sweat it, do you think the body of knowledge sprang fully formed from Zeus', erm, Yamaha's forehead for any of us?

                Just keep going!

                .
                -- Scott
                _____

                2004 ST1300A: No name... yet
                1982 XJ1100J: "Baby" SS Brakes, '850 FD, ACCT
                1980 XS1100G: "Columbo" SS Brakes, '850 FD, ACCT
                1979 XS1100SF: "Bush" W.I.P.
                1979 XS1100F: parts
                2018 Heritage Softail Classic 117 FLHCS SE: "Nanuk" It's DEAD, it's not just resting. It is an EX cycle.

                Comment


                • #9
                  Originally posted by newtoXS11 View Post
                  Just a reply here, not really an update... haven't gotten a chance to work on it yet...

                  I have always had the petcocks on RES. On all my bikes going back to 2005. Even when I park and store them (I just put a catch pan underneath so as not to drip on pavement). I keep the tank as full as possible and am a member of the Church of Seafoam - either that or Lucas is always in the fuel. This has never failed me and so long as the battery has good charge my bikes have always fired right up.

                  The reason for this is that I Ran into a problem with my old Virago and got stranded due to petcock failure which I attributed to age and overuse. If I should still try the "ride it on PRIME" troubleshooting method I will - gotta be honest in that I only have a basic understanding of fuel delivery from a 2 cycle engine perspective and don't quite get how a vacuum system comes into play.

                  As an aside, I would like to thank you guys for helping here. I know how frustrating it can be to advise people with limited topic familiarity (I do computer tech support, mostly for elderly clients) and appreciate your patience. Hopefully my detailed messages are more helpful than aggravating.
                  Hey New,

                  Can we get an "AMEN"! I'm a SeaFoam Devotee as well!

                  Leaving your petcocks on Reserve is setting yourself up for another stranding.. IMHO. Granted, you have the Low Fuel Warning Light to alert you to that status so you can start looking for a station. But warning lights go bad, or the sending unit, also could be riding with the sun in your face so that you might not notice the light....and then already being on Reserve, you can run the tank dry, and then you're stuck on the side of the road without any gas!

                  Also, a catch pan isn't enough in the case of petcock/Octy/carb float needle failure....carbs flood, can flow forward into the intake, past the valves, rings, and down into the oil.....which can then lead to bearing failure and burning up your motor!

                  Okay, you're a techie...so you should no problems setting up a Photobucket account, and then take some photos of your bike, from several angles, so that we can better see what your bike has, etc.! Also, hopefully you've edited your profile/signature to add your bike's year/model so when you post another thread you can include your signature info.

                  Hopefully you'll be able to do the Prime test this weekend, and report back your findings for further troubleshooting as needed!

                  T.C.
                  T. C. Gresham
                  81SH "Godzilla" . . .1179cc super-rat.
                  79SF "The Teacher" . . .basket case!
                  History shows again and again,
                  How nature points out the folly of men!

                  Comment

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