QuestionI have a 1979 Honda CM185 Twinstar which I have been restoring. Got it up and running again and purrs like a kitten. But I have discovered a oil leak that is coming from the drive shaft. The manuals show a oil seal on the end of the drive shaft but don't indicate if you can replace it without tearing down the whole engine. Can you get to it and replace this 3 buck part without tearing down the whole engine? If so is there any tricks to do this. I would appreciate any advice.
Answerhttp://www.powersportspro.com/partsfish/login.asp will show you some illustrations of your bike's parts. I believe that you are referring to the countershaft seal, behind the front sprocket.... ?
OIL SEAL (20X34X7)
From the looks of it, I believe that you can replace the seal w/o engine teardown, which is possible with most engine seals on Hondas that don't have some kind of locating lip on the edge.
Depending on your level of skill and luck, the seal replacement may go easily or you may damage a couple of them in the process.
First, you have to get a sharp pointed tool to drive into the face of the seal and gently pry it out of the crankcase recess without damaging the surrounding area. Next you will have to put a bit of oil on the new seal and then find a driver of the same diameter to use to insert the seal and install it back to the correct depth.
Normally seals are set in at the flush surface of the case, but be sure to observe how the old one looks before you drive in the new one too far. The case probably does not have a stopper lip to keep the seal from driving into the bearing behind it, so you have to go slowly, keep the seal square with the opening and then tap it into place. You may be able to use a piece of PVC tubing or something similar to simulate the Honda seal driver tool for installation. Just get something that is the same OD as the seal. 34mm is just larger than 1 1/8". You may have to browse the hardware store, in plumbing or other areas to find something that is just right.
Bill Silver
