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Crack in bottom cover @ drain plug

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    Crack in bottom cover @ drain plug

    So I have a '79 GS425 with a crappy motor. I also have a spare motor that is in much better shape...except for a small crack in the bottom cover that starts @ the threads of the drain plug. I didn't do it. The bonehead previous owner caused the crack.

    So, as I see it, there are two options:

    1) Remove the bottom cover and have the crack welded-up.

    2) Remove the crappy engine from the bike, pull the bottom cover, and install it on the good motor.


    Sound correct to you all? What do you suggest? How difficult is it to remove and reinstall the bottom cover?

    I know know nothing about these motors. A friend was saying that it's a split-case design and replacing the bottom cover would involve disassembling the entire motor...and then the other one may not fit because they were often file-fit during production. Please tell me that he is mistaken.

    #2
    Well your friend is right in that the engine block is a two piece assembly. But hes full of squat when it comes to changing the oil pan. If you want to replace the oil pan on the one out of the bike you can just get one off ebay and an oil pan gasket and change it in about an hour.

    But lets back up stream a little first. You say the engine in the frame now is junk. Explain this. Just whats it doing...sounds, rattles, squeeling, metalic clanking noises...what??? Doesnt run??? Maybe what you need is to do the maintenance on the engine first. Get the thing sorted and do a full carb tear down and rebuild before determining the engine is junk.

    I had to change an oil pan on my 78 1000E once because of stripped threads. I drained the oil, took off the right side frame cover and the tank. Then just layed the bike over onto an old tire and removed the pan...simple.
    Last edited by chuck hahn; 09-06-2014, 06:16 PM.
    MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
    1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

    NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


    I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

    Comment


      #3
      Where in California are you. Lots of members out there and I would bet some gas money, few beers and a few brats on the grill and your in for some expert help and one great day of learning about your bike...just takes an asking and someone will respond.
      MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
      1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

      NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


      I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

      Comment


        #4
        Heres the service manual


        MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
        1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

        NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


        I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

        Comment


          #5
          Thanks, Chuck. I'm near Healdsburg, CA. About 1.5hrs north of San Francisco. 100% interested in having a motorcycle/beer/brats cookout. Anyone?

          That info is very helpful! Thank you! I'll start looking into changing-out the oil pan.

          To answer your questions - the motor that is out of the bike is the original motor with about 10,000mi on it. That one has the oil pan that the previous owner cracked. The motor that in in the bike is an eBay replacement motor that previous owner installed, instead of attempting to repair the motor with the cracked pan. This replacement motor leaks oil into both combustion chambers (not sure if it's from leaky valve seals or piston rings), needs valves adjusted, has unknown # of miles, and is visibly more worn/weathered. It isn't completely busted. But it has seen better days. A rebuild would cure what ails it.

          -Ryan

          Comment


            #6
            Take the engine out of the bike and get a oil pan gasket on order. Swap the pans and then put the original engine back in. But I would also refresh the valve stem seals, lap the valves, adjust the valves while the original is on the bench. freshen it up and stuff it back in.
            MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
            1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

            NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


            I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

            Comment


              #7
              Yeah. That's more-or-less what I had in mind.

              I had another look at the motor. Are you sure about the "oil pan"? It looks like the "oil pan" is actually the lower 1/2 of the crankcase. It really does look like I would have to completely dismantle the engine to replace the "oil pan" or lower crankcase or whatever it is.

              Comment


                #8
                So no sub cover on the bottom with a bunch of bolts holding it to the bottom of the engine....I didnt see an oil pan in the parts fiche either. I stand corrected then.

                Well then, why cant you just take the engine to a shop and have them weld the crack by flipping the engine over??? Seems like that would be a viable option.
                MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                Comment


                  #9
                  I talked to a shop. They said that they would need to weld the crack from both sides. Part of the problem is that the crack originates in the drain plug threads. Welding from both sides means dismantling the whole engine...

                  Comment


                    #10
                    Not technically disassembly of the entire engine. Take the side crankcase covers off and remove the bolts holding the halves together and split the cases. Pain in the azz to have to do it but not at all a daunting task. Reseal the cases with some threebond 1184 or one of the many other cases sealers folks here have used with success. Just split the cases and dont disturb the tranny.

                    And for the drain thread situation. They make a PLUS 1 drain bolt that you can get at most auto parts places. Its designed just for stripped pan threads. I might even have one laying around.
                    MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                    1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                    NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                    I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                    Comment


                      #11
                      Heres a thread in which the owner says the oversize plug may have actually cracked the hole area. maybe the previous owner of your bike did the same thing??? In any case, get ahold of the guy and see what his solution was. best advice comes from someone that has confronted the same problems.



                      MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                      1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                      NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                      I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                      Comment


                        #12
                        By looking at the parts fiche for that engine, the oil drain plug is in the oil filter cap.
                        Why not simply remove the cap and get it welded and re-tapped?

                        Comment


                          #13
                          The drain plug is definitely not in the filter cap

                          Comment


                            #14
                            The bolt in the bottom of the filter cover is just for draining the filter sump..not the entire engines oil supply.
                            MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                            1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                            NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                            I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                            Comment


                              #15
                              I'd vote for a gob of JBweld (an epoxy) on a surface roughend with coarse sandpaper and well-cleaned with alcohol ...it isn't much good if there is ANY oil on the surface... Being upside down will likely mean a fail with oil seeping out and so drain oil,Tip the bike on it's side and clean clean clean.. two gobs as it runs a bit.Clean and roughen up with sandpaper between gobs.

                              JBweld comes off fairly easily with a file or sandpaper if it's a total fail and you can go back to the intensive solutions.

                              Comment

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