changing c/shaft seal on 125

[Mike Vorndran]

I need to change the seal on the countershaft, and am wondering if it can be done from the outside.

[Kip Kern]

Yes, remove sprocket pull seal, install new seal flush with outside of case.  Have fun!

[Mike Vorndran]

how about the seal size? so I can have one ready. prepping for fun!

[Paul Danik]

Hi Mike,

   First off, welcome to the Penton Owners Group message board family, we are glad to have you aboard.

   I have been thinking about your asking about changing that seal. I am sure that some do leak, and quite possibly your diagnosis is correct, but I think there is something else to check. I have seen oil leak out of the end of the main shaft itself on occasion. The rod that moves the selector key thru the gears moves thru the hollow center of the main shaft, and the end of that shaft is wide open and it fits into a seal in the side cover, IF everything is as it should be.

   I have seen machines with the tranny overfilled leak out the end of that shaft, as well as machines parked leaning over fairly far. Also, the end of the main shaft is slotted to fit into a speedo drive that is built into the side cover. At times those ends on the main shaft get broken off and the shaft does not fit into the side cover seal properly, possibly allowing tranny oil to escape.

   Quite possibly you are correct in your evaluation of a leaking seal, but I just had to throw my 2 cents in....

Good luck and have fun.
Paul

[Mike Vorndran]

Paul, thank you for your input. The end of the shaft is good where it goes into the side cover. I am currently running an ignition only cover and have the shaft end plugged. The fluid is only on the case on the rear of the c/shaft sprocket, which leads me to feel that the seal is bad. ( it is after all how old?) I run 600cc of 80wt gear oil, which is what I believe is suggested. The seal is out and waiting for a replacement. Fun time!

[Paul Danik]

Sounds like you have it correctly analyzed. On a related matter, are you running a case protector? I have been looking thru a lot of Sachs engines lately and the percentage of them that have damaged cases is rather disheartening.

Is this Sachs engine in a Penton? If so if you care to tell us a little about it, and possibly yourself if you don't mind, we would enjoy hearing the stories.

Paul

[Mike Vorndran]

Hi, my bike is a 1973 DKW 125 Hornet (motocross) model, yellow tank. I have had it for about 25 years and has finished the Vegas to Reno offroad race in 1998.I have set this one up to campaign the D-37 GP series on this year with two second places so far. I have stock gearing, elephant ear handguards, brake snake, and fitted a Mikuni on it. I must say the Mikuni makes it fun to ride again! The 3rd round is next Saturday at Glen Helen and will let you know how it goes there. Thanks for the interest! (by the way, what is that c/shaft seal size?) Mikey V.

[Paul Danik]

Mike,

   I hope I have the correct seal as the parts book blow up is not as precise as I would like. If you measure the old seal or the case opening and the O.D. of the main shaft it should show if the seal size I am providing is for the seal you need.  23.4 X 34 X 5 is what the parts book shows.

  Good luck at your event, and thanks for giving us the scoop on your DKW and the races you participate in.

Paul