Announcement

Collapse
No announcement yet.

HELP PLease: GS650G valve clearance HUGE!!! 3.00 shim and has 14 thou clearance

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    HELP PLease: GS650G valve clearance HUGE!!! 3.00 shim and has 14 thou clearance

    My son and I swapped a topend from 1 engine too another. When we pulled the buckets out of the head they all got rearranged. We slid them into the head and have 2 valves I can't get within spec. #3 and #1 exhaust vales are out; one measures 34 and other measured 25 thou over a 2.65 or so shim. All other valves I could bring within spec.

    I tried swapping buckets from another head. No dice. The readings were off by a thou of two.

    I have never seen this before. Only thing I can think of is we have a bent valve?

    Anyone have any ideas?

    Thanks

    Rich
    The GS toys:
    79 GS1000L 1st bike sold many moons ago...
    78 GS550
    81 GS650G The son's
    82 GS650GL parts bike
    85 GS700ES in progress
    85 gs700E parts bike
    82 GS1000GL in pieces
    80 GS1100L in progress

    #2
    Yep, that much extra clearance sounds like bent valves or something is stuck on the seats, holding them open.

    .
    sigpic
    mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
    hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
    #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
    #2 son: 1980 GS1000G
    Family Portrait
    Siblings and Spouses
    Mom's first ride
    Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
    (Click on my username in the upper-left corner for e-mail info.)

    Comment


      #3
      Bent valve sound right.

      Before installing a head in unknown condition it's advised to service it first. At minimum: remove valves, inspect all parts, lap the valves, and install new valve stem seals.
      Last edited by Nessism; 05-05-2020, 07:51 AM.
      Ed

      To measure is to know.

      Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

      Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

      Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

      KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

      Comment


        #4
        Any reason you can't go back to the original head?
        1978 GS 1000 (since new)
        1979 GS 1000 (The Fridge, superbike replica project)
        1978 GS 1000 (parts)
        1981 GS 850 (anyone want a project?)
        1981 GPZ 550 (backroad screamer)
        1970 450 Mk IIID (THUMP!)
        2007 DRz 400S
        1999 ATK 490ES
        1994 DR 350SES

        Comment


          #5
          Orginal head

          Originally posted by Big T View Post
          Any reason you can't go back to the original head?
          I pulled the top end off the "black" engine due to a bad #2 rod knocking. The engine ran well with consistent compression across all 4 cylinders 155-165psi.

          I pulled the silver topend due to bad rings on #2 cylinder and air leaking into the intake of #4 during a leak down test. When I pulled the head I filled the combustion chambers with water expecting #4 to poor out due to a bad valve or poor sealing. I had no loss out of any of the chambers. I don't trust the silver head since I have not found where the leak may be coming from..

          My son is out of work due to covid so we are scraping pennies to get his bike running.

          Thanks for the replies GSR team. I appreciate the guidance.
          The GS toys:
          79 GS1000L 1st bike sold many moons ago...
          78 GS550
          81 GS650G The son's
          82 GS650GL parts bike
          85 GS700ES in progress
          85 gs700E parts bike
          82 GS1000GL in pieces
          80 GS1100L in progress

          Comment


            #6
            See if you can manage some sort of leakdown test to see if that valve is leaking. As noted above, a bent valve or a little chunk of carbon on the seat are the usual suspects.
            1983 GS850G, Cosmos Blue.
            2005 KLR685, Aztec Pink - Turd II.3, the ReReReTurdening
            2015 Yamaha FJ-09, Magma Red Power Corrupts...
            Eat more venison.

            Please provide details. The GSR Hive Mind is nearly omniscient, but not yet clairvoyant.

            Celeriter equita, converteque saepe.

            SUPPORT THIS SITE! DONATE TODAY!

            Get "The Riding Obsession" sport-touring motorcycling podcast at https://tro.bike/podcast/ or wherever you listen to podcasts!

            Comment


              #7
              Put air in the cylinders tonight and both blew hard out the exhaust. I ordered a valve spring compressor tonight. It looks like 1 and 3 exhaust are bent. I'll make sure once I disassemble.
              The GS toys:
              79 GS1000L 1st bike sold many moons ago...
              78 GS550
              81 GS650G The son's
              82 GS650GL parts bike
              85 GS700ES in progress
              85 gs700E parts bike
              82 GS1000GL in pieces
              80 GS1100L in progress

              Comment


                #8
                We opened it a couple days ago. I found both valves bent. The questionable head we are robbing parts from to fix the known decent one. As I was pulling seals since we had the head apart I had 2 snap off at the circlip line.

                Now i'm replacing valve guides we are checking all the specs on the current parts.

                Thanks GS team.

                RR
                The GS toys:
                79 GS1000L 1st bike sold many moons ago...
                78 GS550
                81 GS650G The son's
                82 GS650GL parts bike
                85 GS700ES in progress
                85 gs700E parts bike
                82 GS1000GL in pieces
                80 GS1100L in progress

                Comment


                  #9
                  Realize that when replacing valve guides the valve seats will have to be cut too.

                  Sorry for the run of bad luck.
                  Ed

                  To measure is to know.

                  Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

                  Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

                  Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

                  KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

                  Comment


                    #10
                    No I didn't. Thanks for the heads up. POOP.
                    The GS toys:
                    79 GS1000L 1st bike sold many moons ago...
                    78 GS550
                    81 GS650G The son's
                    82 GS650GL parts bike
                    85 GS700ES in progress
                    85 gs700E parts bike
                    82 GS1000GL in pieces
                    80 GS1100L in progress

                    Comment


                      #11
                      Could you explain why?
                      The GS toys:
                      79 GS1000L 1st bike sold many moons ago...
                      78 GS550
                      81 GS650G The son's
                      82 GS650GL parts bike
                      85 GS700ES in progress
                      85 gs700E parts bike
                      82 GS1000GL in pieces
                      80 GS1100L in progress

                      Comment


                        #12
                        When the new guide is installed it will be every so slightly out of concentric with the old guide. And the guide is the datum for cutting the seats.
                        Ed

                        To measure is to know.

                        Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

                        Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

                        Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

                        KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

                        Comment


                          #13
                          So can they be lapped in or do I need to take it to a machine shop?
                          The GS toys:
                          79 GS1000L 1st bike sold many moons ago...
                          78 GS550
                          81 GS650G The son's
                          82 GS650GL parts bike
                          85 GS700ES in progress
                          85 gs700E parts bike
                          82 GS1000GL in pieces
                          80 GS1100L in progress

                          Comment


                            #14
                            I would think that if they are non-concentric, no amount of lapping would get the valves to seat properly.

                            If the hole in the guide is off by 0.05mm, your lapping would just clean off a small portion of the seat.

                            And, ... if they DO have to address the seats, be sure to check valve clearance BEFORE putting the head on the engine. You might have to trim a bit off the tip of the valve if the seat is a bit deeper than before.

                            .
                            sigpic
                            mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
                            hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
                            #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
                            #2 son: 1980 GS1000G
                            Family Portrait
                            Siblings and Spouses
                            Mom's first ride
                            Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
                            (Click on my username in the upper-left corner for e-mail info.)

                            Comment


                              #15
                              OK. Thanks. Looks like we will make a trip to the machine shop.
                              The GS toys:
                              79 GS1000L 1st bike sold many moons ago...
                              78 GS550
                              81 GS650G The son's
                              82 GS650GL parts bike
                              85 GS700ES in progress
                              85 gs700E parts bike
                              82 GS1000GL in pieces
                              80 GS1100L in progress

                              Comment

                              Working...
                              X