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'82 gs850 runs rough...blows white smoke

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    '82 gs850 runs rough...blows white smoke

    I am a newbie to the gs bikes...I bought one a month ago that runs well and I recently purchased another 1982 GS850GL with 11,000 miles on it. The bike is in great shape cosmetically but the engine seems to have some issues. It sat for two years so I am planning to clean the carbs. It will start and idle but it dies when you give it throttle. I have been able to rev it some and it backfires at higher rpms. There is white smoke coming from the exhaust and there was oil dripping from the exhaust pipes under the bike. I have heard these engines are very reliable so I was wondering if there could be some other problem besides bad rings...esp. with this low of mileage. I inspected all the plugs and cylinders 1 and 2 were wet with oil. I looked in the cylinders with a borescope and didn't see any damage from broken rings. Haven't checked the oil filter yet. Any ideas?

    #2
    Do you like rebuilding engines for fun?

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      #3
      Originally posted by adamjmc View Post
      It sat for two years so I am planning to clean the carbs. It will start and idle but it dies when you give it throttle. I have been able to rev it some and it backfires at higher rpms. There is white smoke coming from the exhaust and there was oil dripping from the exhaust pipes under the bike.
      Any ideas?
      White smoke is condensation when the bike starts in cold temps.
      are you sure it's oil dripping from the exhaust and not water mixed with carbon from the inside of the pipes? (play detective and look where its coming from, or what it is)
      when you clean the carbs, be sure to have a proper fitting air box with the air filter installed or it isn't going to run correctly.

      Originally posted by Skyboy8950 View Post
      Do you like rebuilding engines for fun?
      Last edited by rustybronco; 08-20-2008, 02:10 PM.
      De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

      http://www.thegsresources.com/_forum...35#post1625535

      Comment


        #4
        I'm pretty sure it was oil...it was thick and dark like used engine oil. There may have been some carbon/water junk mixed in but the majority was oil.

        I discovered the importance of sealing the airbox with my other gs850. It had a hesitation that cleared up as soon as I cleaned the filter and put on some fresh weatherstripping.

        In doing my "detective" work I found out something else of interest. with the bike on the side stand the oil shows about halfway between "E" and "F" with it straight up it's way over the "F" mark. Would that mean it's overfilled? If so, then perhaps that's where all the oil is coming from. I've seen overfilled lawn mowers spit oil out the exhaust...would this bike do the same?

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          #5
          If it's to the top of the sight glass, it's too full.
          That is the reason for the 'E' and 'F'. 'F' means full. Over the 'F' is too full.

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            #6
            overfilled lawn mowers spit oil out the exhaust...would this bike do the same?

            Yes.

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              #7
              I guess I'm wondering if having too much oil would cause it to blow out the exhaust or not...

              Comment


                #8
                Originally posted by adamjmc View Post
                In doing my "detective" work I found out something else of interest. with the bike on the side stand the oil shows about halfway between "E" and "F" with it straight up it's way over the "F" mark. Would that mean it's overfilled?
                Yes it would mean it's over filled. the question is with what, fuel?
                detective time again, smell the oil.
                De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

                http://www.thegsresources.com/_forum...35#post1625535

                Comment


                  #9
                  Two things here:

                  If you find that your oil has a strong gas smell to it, get rid of it, immediately. Change the filter to. Then, find out why its passing fuel into the crankcase, usually a faulty petcock, or bad float valves, or im properly set float levels, which would help explain some of your running rough as well. The BS carb design did not incorporate a overflow outlet, so thats where the fuel goes when the bowls are over full. It finds its way up the needle jet, and down the intake manifolds to the cylinders, washing down the oil, and into the crank. Bad news. Running like this will promote VERY short life for your motor. Once you eliminate the problem, whichever it may be, then put fresh oil, fresh filter in the bike, run it for a few hundred miles, then change it all again to assure you got ALL the gas out of the cases.

                  Now, IF your oil DOESNT wreak of gas, you are having a pretty serious blowby issue from the rings/valve stem seals. This will likely require a rebuild, tho it is possible if the bike has sat for a LONG time, the rings simply need to reseat, and are stuck. A compression test will help reveal whether or not you are having a blowby issue.

                  Comment


                    #10
                    The oil smells musty...like there's some old fuel mixed in. I am planning to change the oil anyways. The smell could just be old oil, though. Whatever the case, I guess the only way to find if there's oil getting into the cylinders is to do a compression check and see how it does. Good compression=good valves and rings so the oil must be getting forced in b/c it's overfilled...if that's possible. Bad compression=bad rings or valves and that's prolly where the oil is coming from. I'm hoping for an easy fix...

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                      #11
                      sorry cafekid...I didn't see your post til after I posted mine...I will check the petcock to see if that's a problem.

                      Comment


                        #12
                        Easy fix... Hmmm

                        Well, let me recommend what almost everyone recommends: do the following:

                        Teardown and cleaning of carbs
                        Valve check/adjustment
                        New o-rings (and boots if necessary)
                        New airfilter and airfilter box sealing
                        Oil and filter change. This includes final and secondary drives.

                        This is basic maintenance. Just do it, especially since it has been sitting a while. You really can't have an easy fix, but take a weekend and do it all. It will repay you...

                        Comment


                          #13
                          Is there a good place to get a gasket/o-ring set for the tune up or do I need to piece one together myself?

                          Comment


                            #14
                            Carb and intake orings can be purchase here

                            www.cycleorings.com

                            Complete gasket kits can be purchased here

                            www.Z1Enterprises.com

                            OR

                            www.bikebandit.com

                            Gear oil for the secondary drive and final drive is 85w90 hypoid gear oil.
                            Oil filters can be purchased at the same place you get your gasket kit.
                            From reading your first post again, I would suspect that you taking care of your carbs, replacing the likely leaky petcock and adjusting the valves will solve MOST of your problem. 2 years is a good while for a motor to sit, so its likely the rings just need to free up again, and that will come with running it a bit. You do have a manual right?

                            TCK

                            Comment


                              #15
                              Actually I have two manuals . The first GS850 I bought (the one I ride regularly) came with a clymer manual. My second 850...which this post is about...came with a clymer as well. So, I think I'm set with manuals. Where is a good place to get ignition leads or maybe just the boots? My cyl. 1 lead is corroded or something on the spark plug end. Thanks for all your help, btw. It took me a month before I finally stumbled across a good GS forum online...this one was hard to find!

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