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1982 GS 300 LZ - right plug not firing

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    1982 GS 300 LZ - right plug not firing

    I have a printout from '98 of all the posts from gsresources.com and I have searched the current and past posts from this site. The trouble shooting sections from the shop manual aren't very informative. I hope someone can help me with my current problem...

    I have a 1982 GS 300 LZ (actually 2 of them) and I am trying to resurrect one from sitting for 2+ years. I have cleaned the carbs, replaced the gas in the tank, replaced the air filter, and I have installed new plugs. The right plug does not seem to want to fire consistently... The plug gets very oily very quickly, and cleaning the plug does not seem to help. I seem to remember always having problems with the right cyl...

    Here's the strange part. Every once in awhile, it does fire for a few cycles! The bike really wants to run! I even rode it for a few miles one time with no problem before I started running on one cyl again...

    However, every once in awhile after running one one cyl for awhile, I get a great backfire... I'm afraid of blowing myself up!

    I am thinking of swapping out the right ignition coil from the other bike onto this one. I have already done plugs and plug boot swap with no effect...

    I am also thinking about taking the carbs apart again and using compressed air (I've only used carb cleaner so far to make sure all the jets are clear).

    I'm even thinking about playing with those "factory set" screws to balance the carbs... Am I crazy?

    I'm not very electrically inclined. Mechanically, no problem! BTW, all I have is a multimeter for testing electrical equipment.

    So, any help from anyone on which path to start on first would be appreciated. I know that eventually I'll nail it down but if anyone has a starting point for me, if you let me know I'd apprecite it! Thanks,

    -richd.

    2xgs300lz

    #2
    you need to start by making sure that power is getting to the right coil. in fact you should go over the entire bike and clean every connection and make certain they are all firmly connected.
    Dink

    Comment


      #3
      Already Done!

      Already done! I even slightly sanded the connections to make sure there was metal agianst metal contacts. The points look good, too... All is OK with the wiring.

      There is a constant, strong, blue spark from the plug when it was removed and contacted against the engine case. I was pretty surprised, the bike started up no problem and ran like that for a bit while I was looking at the spark with the plug out of the hole! Maybe next time I'll plug up the hole with a spare plug...

      My next step is going to be taking apart the carbs (again!) and make sure all the vents and jets are clear using compressed air. The only other thing I can think of is the diaphram or the spring. Has anyone ever looked at the carb piston position with the carbs attached, the air box removed, and the engine running? Instead of taking the whole carb apart, maybe I should check this first?

      At this point, I am going for the path of least resistance for troubleshooting and nailing down the exact problem, unless anyone has another suggestion? I'll keep posting progress as I go...

      BTW, thanks for responding Dink!

      -richd.

      2xgs300lz

      Comment


        #4
        have you checked the points/ ignition pickups?
        Dink

        Comment


          #5
          My bike is possessed!

          OK, after replacing the starter relay and completely taking the starter apart for cleaning (It stopeed turning over after jumping from my car after awhile) my bike turns over again. I am back to my original problem, the right cyl is possessed. So, I get the bike running on one cyl, and for a few seconds, every minute or two, the right cyl fires, then dies., then after awhile, kicks in again & dies, etc... It is totally not consistent while running...

          However, what is consistent is that every time I pull the spark plug from the right side, it's wet with fuel. I confirmed again, that with the plug laying against the engine block, I get a healthy spark consistently.

          So, I am thinking that it's either that I'm not getting air (how would that happen?) or that the carb is running too rich. I got a plug rated one level hotter, with no effect. All the contacts are clean and the wiring good...

          BTW, I got my other 82 gs 300 lz running this weekend, all it needed was a new battery and new plugs, plus a little tlc. It was sitting for 6 months without starting, un-winterized. My friend wants to learn how to ride on a small bike, before he gets his own. It runs with no problem! I'm ready to swap carbs...

          -richd.

          2xgs300lz

          Comment


            #6
            Since your flooding on that cyl, sounds like your float is either maladjusted or the needle/seat is bad, allowing too much fuel into the cyl. A way to tell is to drain the bowl of fuel, then while leaving the drain plug out, put petcock on prime, and watch the drainhole and see if fluid starts coming out (you do this while the bike is not running). If the needle/seat is bad, you will see a continuous stream or drip from the drainhole. :twisted:

            Comment


              #7
              The carb float bowl has to fill to raise the float in order to press against the tab which raises the float needle shutting off fuel. If you leave the drain plug out, the float bow certainly cannot fill up and consequently raise the float. With the float bowl installed, with the plug installed in the bottom and the fuel selector set to prime, the float bowl will fill. Fuel will raise the float and that should shut off the fuel flow into the bowl. If it does not, fuel will be seen to come out the overflow tube. (The little black rubber tubes hooked underneath the carbs)

              You can also remove the carb, remove the float bowl, turn the carb upside down allowing the weight of the float to close the float needle and blow into the fuel supply line. If the needle shuts off the flow, you will not be able to blow air through the fuel line.

              Earl


              Originally posted by propflux01
              Since your flooding on that cyl, sounds like your float is either maladjusted or the needle/seat is bad, allowing too much fuel into the cyl. A way to tell is to drain the bowl of fuel, then while leaving the drain plug out, put petcock on prime, and watch the drainhole and see if fluid starts coming out (you do this while the bike is not running). If the needle/seat is bad, you will see a continuous stream or drip from the drainhole. :twisted:
              Komorebi-The light filtering through the trees.

              I would rather sit on a pumpkin and have it all to myself than be crowded on a velvet cushion. H.D.T.

              Comment


                #8
                Whoops....wasn't thinking right... :roll:

                Comment


                  #9
                  Sounded good...

                  Well, that test sounded good the first time I read it, but yeah, that wouldn't work. As it happens, I busted the copper plunger in the stopcock during a cleaning so a prime test wouldn't work for me anyway...

                  I do plan to take out the carbs again, maybe this weekend. Last time I did, I put the float levels as per specs. This time, I'll put the right float a few tenths of a mm above spec (so the float "floats" lower). FYI, right now, nothing comes out the breater tube...

                  BTW, the bike starts up really nicely after the starter cleaning. It starts a lot quiter now, too. The only problem is putting the starter cover back on, it's a pain in the butt! I should've done that with the cam chain tensioner off, but then I wouldn't have been able to get the bottom bolt on. I must've spent 2 hours trying to figure out how to get the starter out of the engine block with the cam case in the bike frame, and another hour putting it back on... A combination of a vice grip, an old ratchet socket and a hex key did it! With regards to the starter cover, I gotta think it's like tetris, some combination of angles will work. Maybe with the carbs out?

                  I started it up again today... It did the same thing. It'll run on one cyl for awhile, then on both (revving high due to the adjustment to the accelerator so one cyl can run the bike) then it'll die off, then restart again. Gremlins perhaps? I thought that occurred only on British bikes!

                  On another note, I found a '84 GS 300 at Union Salvage in Houston Tx, mostly complete. If worst comes to worst, I'll buy a spare set of carbs.

                  I'll post back after the float adj. Thanks for the support all!

                  -richd.

                  --
                  2xgs300lz

                  Comment


                    #10
                    the bike is running!

                    OK this is what I did:

                    1) I took off the carbs, adjusted the float level, and put them back in the bike. I was pretty surprised, I was able to do this all in less than 40 minutes, and that included wrestling with the starter cover for a few minutes...

                    2) There was no effect with the right cyl. I ended up taking out my multimeter and checking the contacts that attached to the ignition coils. Both sides were OK.

                    3) I swapped the ignition coils, and the then right side was firing OK, but the left side was now not firing at all! I knew 90% sure at that time it was a bad coil. I went to the motorcycle junkyard and found a spare set ( just to make sure I got a good coil and since there were no testing gear available) and put them in-line.

                    4) Immediarely, the bike started and runs like a dream...

                    So, it was a bad coil all the time! All in all, it took me a couple of months, a couple of carb cleanings and re-builds, a busted starter relay, a starter cleaning, and finally new ignition coils to solve the problem. So far, the bike runs like a champ!

                    I knew it would take me a bit to nail the problem down... I hate electrical troubleshooting, but in the end, it was better an experience than I thought. I appreciate the support, thanks all!

                    -richd.

                    --

                    2x82gs300lz

                    Comment


                      #11
                      Sorry I didnt post on this one, that was my thought( I had a similar problem) The guys giving you advise are much more knowledgeable than I am on this subject so I didn't post.

                      Comment


                        #12
                        Skip you should not let that attitude ever stop you from replying.
                        As it turned out most of the replies were pointing to the carbs being the problem not the coils, so you would have been correct and may have shortened the time taken to repair this bike. Remember these forums are about everyones opinions, most of us are replying from or acquired knowledge from other peoples replies as well as our own experience. being aware that very few of us are actually mechanics let alone motorcycle mechanics.
                        Dink

                        Comment


                          #13
                          I agree...

                          That's it exactly, I was looking for "quick fixes" or "quick tests" to shorten the job... Thanks Dink!

                          What was wierd with this problem was that when I had the plug out and resting against the crankcase, the spark looked OK. Why one good looking spark from one coil worked and another did not, I don't know.

                          I turned the bike over today (45 degrees F) with only a second on the electric starter... This is how I remember GS's! Can't wait to ride it to work after the nasty weather stops...

                          My next job is to replace the bolts on the engine for the exhaust pipes, I snapped the head off one a few years back and it needs replacing, might as well do them all. I was recommended by a friend to get SS bolts this time around...

                          -richd.

                          --
                          2x82gs300lz

                          Comment


                            #14
                            Re: I agree...

                            I coat the threads on those bolts with Never Seize when I install them.
                            I've never had another frozen bolt since I started doing that. (we wont discuss how many years that is :-) :-) :-) )

                            Earl


                            [quote="2xgs300lz"]

                            My next job is to replace the bolts on the engine for the exhaust pipes, I snapped the head off one a few years back and it needs replacing, might as well do them all. I was recommended by a friend to get SS bolts this time around...
                            Komorebi-The light filtering through the trees.

                            I would rather sit on a pumpkin and have it all to myself than be crowded on a velvet cushion. H.D.T.

                            Comment

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