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    #1

    Problem: Electrical or Carbs

    Something strange just popped up with my bike (1980 GS750L; K&N pods; re-jetted; 4-1 exhaust). Here it is: the bike idles and runs excellent until I hit about 50mph. At 50mph it starts to sputter (as if it is not gettin' enough fuel). However, in a lower gear I can really "get-on-it" and I don't feel any sputterin'. So in low gears with high revs it runs fine. In addition, yesterday I was in third gear pullin' about 7K revs and it totally shut down. I immediately checked (after pullin' over to the side of the road, obviously) fuses and found that the 'ignition' fuse had blown. I replaced the fuse, the bike started right up but once I hit 50mph it started sputterin' again. I know this sorta indicates a carb problem, but what about the blown fuse? This just happened, outa nowhere. The bike has run great for the past 7 years and I haven't made any changes. (I do of course change plugs, clean carbs, charge battery, etc.---- Although I haven't charged the battery since the Spring)

    Could it be plug wires, plugs, ignitor, battery, coils?????? Please help me, my baby is sick!!!!!!!

    Much Appreciation for any knowledge/experience you can provide. I've got all my other bikes tore-down so it is essential that I get this fixed within the next few days or I'm headed for severe withdrawal!

    Thanks Much from the Mountains: David
    Tags: None
    #2
    running better at higher revs and missing at lower rpm could easily be a plug or plug wire.

    I just replaced a Plug wire and boot yesterday for exactly the same symptoms. Running fine now.

    I just did a temp fix and put on an NGK wire and boot with one of their connectors. I will be doing it up permanently when I get a chance.

    Comment

      #3
      Well, I've had similar sputter problems and found my Fuel Line was kinked a bit, thus restricting the fuel. I had recently been working on it, so was the first place I looked.

      I've also had a "Miss" of sorts, not quite a sputter, but I guess you could call it that. I ended up losing a cylinder. Turned out I had blown A plug boot. So, after I got 4 new boots ($4-5 each) I trimmed the plug wire back about 1/2" and screwed em on and running fine ever since.

      I never blew a fuse, so not sure about that one. However, check the fuel line and check your plug caps and wires. Easy enough to do. Cheap enough to replace also.

      Good Luck.

      Comment

        #4
        Blowing the fuse - sounds like your R/R is letting too much voltage through.
        The voltage at your battery terminals at any RPM should be no higher than 15 volts DC. You're probably seeing it blow in higher gears because you spend more time at high RPM in the higher gear (I'm guessing that you're using the lower gears for brief periods of high RPM for acceleration purposes only - like most of us).

        Comment

          #5
          Interesting, aside from my low speed problems that come and go (still have no idea about that one yet) my bike has recently picked up a high speed problem. Almost without fail when I am in 5th gear it refuses to go over 50-55 and gets this kind of growling noise, like it is fighting to push past something, it will gradually slow down to 40-45 and then somtimes quit. However in lower gears I can get higher rpms and go faster. One thread suggested removing my carb vent hoses, that didn't help though for me anyways. Apparently for some it did. How do I change the plug wires, mine appear to be glued into the coils?

          New battery and Honda R/R whats next? Atleast my signals work better :*)

          Thoroughly confused...
          intercessor

          1985 GS300LF 14,000

          Comment

            #6
            Sounds like one cylinder isn't firing. My 450 which is also a two cylinder will go 55 on cylinder but it has that weird growl because the other cylinder doesn't fire. Mine was fouling the #2 plug because of the petcock diaphragm being bad. Pull your plugs and see what they look like. Replace with fresh and see what happens.

            Comment

              #7
              Why would a plug foul if the petcock was not working properly?I forgot to mention that if I let the bike quit it takes 5 or so minutes and then it will start again...

              Still trying to fifure out if I have electrical or carb problems, the shop cleaned the carbs last year for $250+ so I guess I am leery of taking it back.

              Comment

                #8
                thanks friends

                Thanks for the input. Last night I piddled with it; while it was running I checked the "fit" of the plug boots and found one was loose (when it knocked the hair off my butt). I'm done at work for the day (man I love Fridays) so I'm gonna go home and replace the coils, wires and plugs to see if she runs like a dream again. I'll post later or tomorrow to update the sicheation (sit-chee-ay-shon). Thanks again for all your help. MAN I LOVE THIS SITE!

                God Bless those in the path of Natures Destruction

                Best Regards: David

                Comment

                  #9
                  lay the plug on motor with ign on then shake wires

                  My prob wasn't much different than yours and my bike ran great all summer long. First was the wire from the end of the cranksahft that plugs into the ignitor, I bypassed a terminal here (cut it off and hardwired the connection). Second was the terminal from ignitor to coils, did the same. I can't be sure if I solved the prob for sure because of a big rain storm so short test ride. Good luck.

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