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    Low rpm misfire

    Don't know where to turn next. 83 gs1100e, ran great. Put a Vance & Hines and K&N pods on with DJ stage 3 kit. Started the bike and the reg/rect. went up in smoke before my eyes. Put in the new elctrex stator and rect. Now the bike has a perm. misfore between 2000 and 3400 rpms. From 4000 to redline the bike runs fantastic. Now I have been working on a set of Bandit carbs as well and it still has the same stumble/misfire. Any help would be appreciated.

    #2
    What throttle position is the stumble at? If you're between 1/8 and 3/4 it probably is the jet needle adjustment. If you followed the Dynojet jetting instructions they tend to be on the lean side. Especially on the needle. Try putting the clip on the needle down two notches which will raise the needle and richen it up.

    On the new R/R did you use the same grounding method straight to the R/R body? If you did cut the eye off the ground and solder a wire and connect it straight to the negative post of your battery.
    Last edited by chef1366; 06-04-2007, 09:27 PM.
    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.

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      #3
      I cut the ground and connected it direct to the ground post. I have tried every needle and main jet combo possible. I have had it real lean and real rich. It also does it with the other set of carbs. It happens at any position between those rpms. Is there any ignition problems that would have these symtems? I have tried pilots from 30 to 55 as well.

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        #4
        Try and clean your ignition advance.
        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.

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          #5
          Works smoothly and is very clean. I am really puling my hair on this one. Its just a pain keeping it over 4000 all the time. Idle is no problem.

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            #6
            Maybe you fried a leg of your stator and your battery is weak? If it isn't carb related what could cause a missing symptom at a certain RPM. HHMMM.
            You still have the stock igniter? If it isn't the advance that would be my guess. Especially since you sent a shock wave through 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.

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              #7
              Not sure why, but I'm thinking electrical.
              One way to help separate electrical and carb issues is to try holding the throttle at a specific opening. Cruise in 5th gear at 3,000 rpm (your problem point) and while keeping the same throttle position, tap into 4th and then 3rd gear or even 2nd. The rpm's will rise enough to change performance as you've noticed. As long as the throttle is held steady at the various engine speeds, any performance changes would more likely be electrical related.
              The idea in your case is, if you have a specific pilot circuit problem, and you keep that specific throttle position during this test, then changes in rpm won't significantly change performance. You'll have a problem as long as you're running on the pilot circuit. But if performance does change significantly, then it's most likely rpm (electrical) related, as that's the only thing changing.
              This is not an absolute test, but something I read about many years ago and have tested myself. It does more often than not, point you in the right direction.
              And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
              Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

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                #8
                Yes, it seems to be rpm reated and not throttle position. I don't seem to have any batt. issues now that I replaced the stator and rect. I found my service manual and will begin checking elec. parts tonight. I'm just not sure where to start.

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                  #9
                  Originally posted by j31driver View Post
                  Don't know where to turn next. 83 gs1100e, ran great. Put a Vance & Hines and K&N pods on with DJ stage 3 kit. Started the bike and the reg/rect. went up in smoke before my eyes. Put in the new elctrex stator and rect. Now the bike has a perm. misfore between 2000 and 3400 rpms. From 4000 to redline the bike runs fantastic. Now I have been working on a set of Bandit carbs as well and it still has the same stumble/misfire. Any help would be appreciated.
                  Re-reading this in order of events, putting the pipe and pods on wouldn't cause the problem. I suppose you could disturb a wire somewhere but I don't see how that would smoke the RR. Maybe it just decided to go. I also don't see how the new RR could contribute to the problem, other than a loose connection??
                  I'm assuming by "misfire", you mean it's missing between those rpm's and not an actual backfire.
                  It could be a poor/loose connection somewhere. Higher rpm's often "help" a poor/loose connection conduct electricity better. Higher rpm's will also change vibrations through the bike and it's possible that lower rpm's effect the connection. If the smoked RR really did cause/allow another part of the electrical system to be damaged, I'm not sure why it would only show up at lower rpm's.
                  If you have a manual, it may be best to start testing parts. First, you must be sure all connections, including grounds, are solid and clean and you have correct voltage at the battery. All plug leads must be inspected for any possible arcing. Test each coil at the primary terminals and then at the secondary (plug cap to plug cap) for correct resistance. Check the stator and RR. The "stator papers" is good info at this site to help you check things. The ignitor needs to be checked and you need a model specific manual to follow testing directions.
                  It sure seems like a bad connection to me. Hope you can find it.
                  And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
                  Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

                  Comment


                    #10
                    So far I've tested the ignitor and coils as well as the signel generater. All pass according to the manual. I soldered all the elec. connections and hooked the rect. ground straight to the batt. post. Tonight I pulled the carbs again and sprayed the pilot tube with carb clean and it came out of all the pilot holes. I'll keep looking.

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