Topic: gearbox output shaft seal!

[daniel son]

i cuurently own i honda cb650z 1979 and i have just noticed that when you it on its side stand you get a nice flow of oil coming out from where the front sprocket is. is this due to the gearbox outputshaft seal leaking? i also would like to know if the seal can be changed without dismantling the engine?
many thanks dan

[dusterdude]

probably and i think so

[tmart]

I just put one in my 350 four,I dont know if it is the same,but the new seal has a little rubber dowell on it to line it up when assembling cases,but i just took a razor blade and removed the dowel and installed from the outside.On the 350 there is a small hole in the bore and a coresponding hole in the seal that you have to line up,other than that it was a breeze and i have no leak at all there anymore,hope this helps

[333]

I just did the exact thing on my 350F.  My local guru suggested what you did ( his exact phrase was "LOP IT OFF AND RACE ON IT").  Even the factory manual doesn't say.

So, race on it!

[daniel son]

its ok, panic over, no need to pull the gearbox apart. i have looked into it further as i didnt strip it down when i noticed it and have found that it is in fact the gear selector shaft seal that had popped out, so i pushed it back in and it doesnt leak anymore. thanks for the help though. i think i will replace it anyway.

[tsflstb]

On the 350 there is a small hole in the bore and a coresponding hole in the seal that you have to line up,other than that it was a breeze and i have no leak at all there anymore,hope this helps

I'd personally feel a lot warmer and fuzzier if I split the cases to replace that seal.  I'd want to have that locating dowel in place to make sure the seal doesn't "walk" too much.  That little oil passage in the seal is very, very critical.

I've had the unpleasant experience of a siezed transmission because that oil passage wasn't flowing.  It will tend to happen at high speeds as the insufficent oil flow breaks down the lubricant.  Things that are supposed to spin like this freewheeling 2nd gear, and then your rear tire will suddenly stop spinning (at 70 mph in my case).  This sucker wouldn't budge with a shop press.