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80 GS750L keeps dropping Cylinder #2..... No clue why

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    80 GS750L keeps dropping Cylinder #2..... No clue why

    I have a 1980 GS750L that was sitting for some time. Well in the last 6 months I have brought it back to life. This issue started a few weeks ago. I just was out riding the back roads of Ohio... and the bike starting loosing power.. Would barely accelerate and would stall every time I would stop. Got home and the valve cover was just puking oil out the front. So I let the bike sit for about a week. Cleaned off all the oil. Started the bike... Only running on 3 cylinders (1,3, & 4). I have spark... So thought it was fuel related (carbs where professionally cleaned and rebuilt over the winter), took the carbs off and inspected #2 carb for issues. Took the jets out, sprayed carb cleaner threw the ports, and put it back on the bike. Still not running right. So I decided to adjust the valves (never been adjusted). All the valves where out of adjustment. Took the bike out on the road, and it ran great! All 4 cylinders firing and noticed a big difference in power. 2 days later, go to ride the bike... Its running great, 20 mins into the ride, I could feel a lost in power, and difference in the exhaust tone. Pulled over and #2 pipe is warm, and the other 3 are super hot. Went to ride home, prob. 3 mins before I got to my house, cylinder 2 came back, and it ran great. Went for a ride today... Same thing. Had all 4 when I left, 3 when I got home....

    Any ideas?

    On a side note, fuel has dumped out of the hose that is connected between carb 1 and 2 when running. Happened twice. Once when I just put the carbs back on the bike and the second time was when I was sitting at a stop light right before I got home.

    Here is my set up:
    Rebuilt carbs w/ Dynojet Stage 3 jet kit
    Straight pipes (no mufflers)
    Pod Air Filters
    Sportster tank w/ Harley petcock

    #2
    Float level in carbs or a faulty petcock. Pull vacuumline off and check and see
    If it has fuel i. It. If it does that is your problem
    1984 GS1100GK newest addition to the heard
    80 GS 1000gt- most favorite ride love this bike
    1978 GS1000E- Known as "RoadKill" , Finished
    83 gs750ed- first new purchase
    85 EX500- vintage track weapon
    1958Ducati 98 Tourismo
    “Remember When in doubt use full throttle, It may not improve the situation ,but it will end the suspense ,
    If it isn't going to make it faster or safer it isn't worth doing

    Comment


      #3
      Check the resistance of your right side coil. Make sure its around 300 ohm. Also, unscrew the boot connected to the wire, and look for corrosion, if there is some, trim it back with wire cutters, reattach and you should be good.

      Comment


        #4
        Check your oil level, maybe your harley petcock isn't right or your "professionally cleaned and rebuilt " carbs have bad needle seats and your crankcase is overfilled with fuel.
        1981 gs650L

        "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

        Comment


          #5
          Pull the vacuum line on the petcock and see if it has gas in it.
          1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
          1985 GS1150ES stock with 85 Red E bodywork.

          Comment


            #6
            Originally posted by yoshisakan View Post
            Check the resistance of your right side coil. Make sure its around 300 ohm. Also, unscrew the boot connected to the wire, and look for corrosion, if there is some, trim it back with wire cutters, reattach and you should be good.
            Corrosion on coil side of the wire or plug side of the wire?

            Thanks everyone for your input

            Comment

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