Topic: First oil leak

[Peterengland]

Apart from routine maintenance I have not had to 'get into' the bike at all but now I have oil leaking from the gear shift shaft. Is this a simple o ring type of seal and is it as simple as it appears?

here's hoping

[70CB750]

What bike?  You can use CMSNL schematics to check assemblies out.  Like this one:

http://www.cmsnl.com/honda-cb750f-750-super-sport-1978-usa_model7240/partslist/E++11.html#results

[Peterengland]

76 cb550

[Duanob]

Looks like you're going to have to 'get into' the bike. At least the sprocket cover. As 70CB750 says look over the schematic and find the correct seal number then search google. In fact you should replace all the seals while you're in there. The main output shaft seal, the check to see if the oil pump o-rings (3 each, 1 large and 2 small) are leaking as well. Parts are cheap. On top of that check the wear on your chain and front sprocket, it's all there and accessible. Do it all once you won't have to take the cover off many times, ask me how I know. 

[dave500]

check the oil pump also which is behind the chain cover,leaks from the pump can make it appear the other seals are leaking,if when you remove the cover theres a quarter cup of oil in the void section that covers the pump itll be leaking.

[Peterengland]

Thanks for the advice. Although I owned a 400/4 back in the 80's as soon as it had something wrong I got rid, now I have the bike I always yearned for but will need support from you more experienced guys.

[Peterengland]

Taken the side cover off and there is no sign of oil at all, so I cannot make out where it is coming from, can it migrate along the shifter shaft to the lever itself?

[riverfever]

I don't have a ton of experience but I dealt with an oil leak on a 650 and now my 500 and both were from the shift shaft seal. Both ran down the shift lever and, eventually down the kickstand and made a nasty mess of things. On both bikes, when I pulled the left cover, there was considerable oil inside the cover waiting to drip down. In order to determine what the issue was on the 650 (this was a friend's bike and he didn't want to spend any money) I cleaned the inside of the cover thoroughly as well as that side of the motor, reinstalled the cover and then took it around the block. It was easy to see the oil weeping from that seal then. On my 500, I just cleaned everything really well and then replaced all of the seals. For some reason, the new shift shaft seal is still leaking so I'll need to go in and replace that one again and see if there is anything funky going on with the shaft itself that's causing the seal to not do its job.

[dave500]

run it with the cover off and make sure the pump isnt leaking,it blows back and can be hard to track down.

[Peterengland]

Just taken it for 10 mile run and no sign of oil but as I have a new seal I might replace it anyway.
Can this seal be extracted with just the side cover off and slid along the selector shaft?

[riverfever]

Yes. There is a thread somewhere that documents drilling the seal (carefully with a small bit) and then threading a screw into that hole and using pliers to essentially yank the seal out. Just be careful to not scratch the shaft as that might damage the new seal.

[goldarrow]

I used a hook picking tool and carefully pull it out.  Clean the area, lube the new seal slide it in and slightly tap in place using small broom handle