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Valve timing and Chain Rubbing, HELP!

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    Valve timing and Chain Rubbing, HELP!



    Here is a picture of something I uncovered in the process of changing out the breather cover and Valve cover gasket. Hopefully everyone can see the pictures I posted. Anyways I pulled the cover off and a noise I had suspected as something rubbing metal was spot on This is in the middle where it looks to be a chain tensioner is of the valve cover?

    My issue: I have read through my Haynes and I can't seem to find anything about adjusting this part and this is my first bike so I'm kinda going balls to the wall on this one. I was going to make a few gasket changes and find out if my stator is the cause of my bike not turning over but after I pulled the tank off I've now ordered new plugs, bought coils off of ebay, new air filter (I think it was the orginal),and trying to figure out what to use for the rubber fittings to hold the tank in place. Anybody have any ideas on this one?

    I don't want to put the valve cover back on till I figure out the rubbing issue and from what people tell me I need to check the valve timing now. I read the book but anyone have insight on how to do valve timing and HOW DO I STOP THE CHAIN RUBBING?

    #2
    Sorry broke the cardinal rule of posting. It's a 83' 850G

    Comment


      #3
      that rubbing in the first pick looks impossible if the idler pulley is functioning correctly. maybe Im wrong on that, but I just had mine all apart and it looked like the chain was held well below all that.

      how much slack is in chain? when you turn the crank to set the timing marks all the slack will be at the back of the chain (side nearest back tire) see if its sloppy loose or not.

      also snap a pic of the head with the tensioner and chain as clear as possible.

      also, is the chain showing wear where its rubbing? is it the whole length of the chain or maybe a stiff link standing up going through there?

      sorry I have more questions than answers.

      Comment


        #4
        Alrighty I'll have to snap some pics tomorrw. I was in a hurry yesterday and just used my camera phone to take the picture.

        If it helps any the pictures are of the middle part of the Valve cover just on either side of the Idler. Basiclly the highest point the cam chain travels. I'm guessing that the Chain Adjuster needs to be tightened but I'm not sure how tight and if I read right this is how you adjust the Valve timing?

        Forgive me if I'm way off on this but as a newbie just trying to apply my common since with regards to the mechanical parts

        Comment


          #5
          the chain runs under the idler, what you are calling a tensioner, it should go up over the cams and under the idle pulley.the idle pulley is non adjustable. tension is adjusted automatically by the tensioner screwed into the back of the cylinders under the carbs.

          If the chain has slack in it with everything installed, the chances are a guide is broken/worn out.

          Im curious though, is the chain run over the idle pulley? my valve cover is back on or Id snap a pic real quick.

          as far as timing, just set the pointer on the crank to the hashmark for #1 cyl. and look where the #1 pointer on the exhaust cam is, it should be even with or slightly below the surface of the head,where the valve cover mates.

          there should be 20 pins from the number 2 pointer on the intake cam gear and the number three pointer on the intake cam. if you dont haveta remove the idle pulley for any other reason you could use a dab of paint or something to mark the pins at the arrows, then rotate the engine to count pins between arrows as you cannot see them while they are beneath the idler pulley brackets.

          *note* I am presuming the 82 and 83 gs850 are identical.

          Comment


            #6
            a picture is worth a thousand words:

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              #7
              I posted some better pictures along with some others so maybe somebody could try and help me out with my original questions.

              My coils should be here next week so I really would like to try and find out what needs to be done so I can maybe hit the road again next week. Especially with these DA$* Gas Prices

              Comment


                #8
                Is it possible that if the idler pully bolts were loose (backed out) enough, the chain could actually hit the valve cover gasket? Just a thought.

                Ace.

                Comment


                  #9
                  I would have to say that is a good idea if it is possible. I poked around with it a little and it wasn't loose at all. I inspected the chain and it looks like it's a consistant rub on the chain from the part I could see. I pulled on the chain between the Idler and Crank and the chain seems to have about 5-10MM play. But again I don't know if that is normal since this is the first case I've cracked open.

                  Comment


                    #10
                    If you bought this bike used it could be a previous problem that was fix except for the war wounds.
                    1166cc 1/8 ET 6.09@111.88
                    1166cc on NOS, 1/8 ET 5.70@122.85
                    1395cc 1/8 ET 6.0051@114.39
                    1395cc on NOS, 1/8 ET 5.71@113.98 "With a broken wrist pin too"
                    01 Sporty 1/8 ET 7.70@92.28, 1/4 ET 12.03@111.82

                    Comment


                      #11
                      looks like the idler gear is installed properly, as long as the bearings in the idler are good, then your problem is somewhere else.

                      (pics are great btw)

                      I would pull the tensioner out from the back of the cylinder, make sure you tighten the set screw first, and see if something obvious is wrong with it. also look and see if one of the guides is broken or worn out.

                      I think 10mm of free play in the chain is too much when everything is installed, I didnt check mine in depth but it seemed like maybe a couple mms at most.

                      edit-you can easily pull the front guide up from where you are at now, although the exhaust cam will need to be removed. if you are gonna do this work yourself its about time to dig deeper into it I think.

                      Comment


                        #12
                        Yeah I kinda figured digging deeper with the problem. :? I haven't messed with the Tensioner at all so I probably take that approach first. It may have been fixed from the PO b/c it did run great the first 3 months I had the bike.

                        I'm getting close to being tapped out b/c I still need a new Stator (Least that what I think stopped my bike from starting in the first place and the hours of reading and testing I've been trying to do).

                        So on the Valve timing. If you look at the picture "Left Front A". I supposed to line up the cam and count the pins from that point? If that is the case I may have read it before but I don't know how to manually advance the cam to set it to the right mark.

                        Comment


                          #13
                          hmm, I thought you had said you heard a "grinding "noise while its running? If you dont hear any noises then maybe it is fixed, assuming its not...

                          remove the ignition pickup cover, and use a 19 mm wrench on the end of the crankshaft to rotate the engine. there is a mark for 1 and 4, and opposite those a mark for 2 and 3. line up the mark for 1+4 with the pointer.

                          then look at where the exhaust cam is, on the sprocket there are arrows. the number 1 arrow should be at roughly 3 o'clock, in line with the top of the cylinder head or slightly below.at approx 12 o'clock on that same sprocket is an arrow for number 2. there should be 20 pins from that one to the number 3 arrow on the intake cam sprocket.

                          always rotate the engine clockwise, do not counter-rotate while setting cam timing.

                          once youve rotated the engine check slack where the chain falls off the back of the intake cam.

                          I would also rotate the engine through a few complete revolutions and look at the chain, see if you can see anything weird going on. maybe even set the cover on, and see when exactly it hits.

                          do all this before removing the tensioner.

                          Comment


                            #14
                            you shouldn't be able to realy move the chain any, I suspect the PO may have locked down the tensioner by mistake.

                            put the bike on the centerstand and get the bike into fith gear and turn the wheel forward to turn the crank and take up any slack on the front side and between the cams.

                            loosen the lock nut and set screw on the tensioner and see if you hear the plunger snap up the slack.

                            this would not be the first time that a tensioner was locked down by mistake, and it would alow the chain to slap around and that could be the cause of those marks on the cam cover.

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