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how to clean transmission oil out of a 2 stroke crankcase?

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  • #447174
    outdoorsman310outdoorsman310
    Participant

      i have an old 2 stroke dirt bike. the oil seal between the engine and transmission failed. the engine sucked up oil into it while runnng and created a gritty substance or it seemed that way if you touches the oil that was on the piston and cylinder. i removed those. I am putting in new rings and dont want to have any damage caused by old transmission/motor oil in the engine. all the bearings have no play. I want to know how to get the oil out of the crankcase. this is an air cooled 2 stroke it is a ke250 and it is almost impossible to find parts for. i got lucky and was able to find one part. i am getting rings from a machine shop

    Viewing 15 replies - 1 through 15 (of 16 total)
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    • #447175
      college mancollege man
      Moderator

        try spraying brake clean.

        #447176
        outdoorsman310outdoorsman310
        Participant

          could that ruin a seal?

          #447177
          college mancollege man
          Moderator

            I don;t think so. brake clean usually can be sprayed on plastic. what type of seal is it?

            #447178
            outdoorsman310outdoorsman310
            Participant

              the seal between the crank ant the flywheel where the electronics are i could try to clean it with the old seal off. still trying to find a new seal.

              #447179
              outdoorsman310outdoorsman310
              Participant

                i might be thinking of carb cleaner

                #447180
                99_XC60099_XC600
                Participant

                  My passion is snowmobiles and I’ve been dealing with 2 strokes for a long time. If it was me, I wouldn’t take any chances. I would just take the whole thing down and split the case and clean it thoroughly.

                  If you suspect there is any type of grit or other contaminants in the case. Take the opportunity know to clean it. The grit your probably seeing is the metal particulates that were trapped in the ATF fluid from the gear wear in the trans.

                  #447181
                  college mancollege man
                  Moderator

                    I would think carb cleaner would be more aggressive than brake clean. can the seal be removed?

                    #447182
                    outdoorsman310outdoorsman310
                    Participant

                      i think the grit was either carbon in the oil or metal/clutch particles. i dont really want to split the transmission and engine but i might if i feel the need maybe i will run an old shirt through the crankcase to try to clean it. what is a good price for rings from a machine shop?

                      #447183
                      Robert McMahangaseousmercury
                      Participant

                        Do not use brake kleen or any break cleaner!!!!! It will ruin the seal because of the high concentration of acetone. Acetone will eat the plastic and dissolve the seal. My personal opinion as a chemist would be mineral spirits. you could use k-1 grade kerosene as well, however, you’ll have less fumes with the spirits. I would take the case apart and use a tooth brush or dish brush. If you want to just flush it I would pour mineral spirits in filler and take out the drain bolt and just keep circulating what comes out. This won’t be as practical or effective, but it will definitely get something out. How dirty is the transmission fluid?

                        #447184
                        outdoorsman310outdoorsman310
                        Participant

                          there is no filler or drain bolt. i have the top end off so you can see the crankshaft and stuff. could i use gasoline to clean it out? the fluid is not too bad. only has a couple hundred miles on it. also would overfilling the transmission ruin the seal? thats what I stupidly did. the seal was on its way put any way.

                          #447185
                          Robert McMahangaseousmercury
                          Participant

                            you can use gasoline. gasoline is more volatile so you’re going to have to deal with more fumes. I would do this outside. over filling may have caused the failure by putting excessive pressure on the seal, however, the seal was probably on its way out from age and deterioration from contact with the oil. The dirtier the oil the more acidic it becomes for several reasons. Good Luck!!!

                            #447186
                            99_XC60099_XC600
                            Participant

                              I would still take it down. Even if you do clean the case. You still need to resolve all of the fluid that’s made it way into the crank bearings.

                              #447187
                              outdoorsman310outdoorsman310
                              Participant

                                i dont want to take it apart for these reasons. I have never split a motorcycle transmission before, it will be alot of work, and it has a gasket made out of a goo stuff from the factory and i dont want it leaking.

                                #447188
                                EricTheCarGuy 1EricTheCarGuy
                                Keymaster

                                  I don’t recommend brake clean or gasoline instead use mineral spirits as this is what is is most parts washers, it seems to do a good job and it doesn’t seem to ruin rubber parts. That said if the oil’s are similar it might be a waste of time, you might be able to just change the oil in the crankcase a couple of times and you’d be fine, not sure however but it’s worth a thought in my opinion.

                                  #447189
                                  outdoorsman310outdoorsman310
                                  Participant

                                    I put mineral spirits in there and dumped most out of the bearing before i put the seal on. i got the rest out with a leaf blower and a towel now the bike works.

                                  Viewing 15 replies - 1 through 15 (of 16 total)
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