Topic: oil behind the ignition cover 79 cb750

[X79CB750X]

I went to check the ignition timing on my bike today and when I took the ignition cover off oil spilled out.  Now since there isn't supposed to be any oil in there..any ideas?  A bad seal up the line somewhere?  Also since there is now (or at least was until I opened it) oil in there how much damage is happening when I run it?  I have to ride it for the next two days and won't get a chance to fix anything.

[Bob Wessner]

Yes, there is a seal back there. Unfortunately, it is a lipped seal so the proper fix is to split the cases. There are some folks who have successfully replaced it without splitting. You might do a search for threads on that. How much oil are we talking about? Mine leaks a bit, measured in drops actually, I just live with it.. so far.

[X79CB750X]

Hi Bob!

Well the oil kind of took me by surprise when I opened the ignition cover, but I would say there was about a 1/4 cup.  Now unfortunately I am the new owner of the bike which is in immaculate condition, so I'm not sure when if ever the ignition cover was ever opened.  The last owner, a good friend, was not how shall we say mechanically inclined.  So it could have been oil built up over the last year.  For now would making sure all the oil is drained out of it and then letting it go for a few weeks to see how bad the leak actually is be a bad idea?

[Bob Wessner]

A quarter cup sounds like a lot! It's hard to believe that much could accumulate back there unless the weep hole at the bottom of the cover is blocked. If, after a ride, I put the bike on the side stand, there might be a very small amount pooled towards the back. If I park it on the center stand, a few drops might leak out, but I just wipe it with a paper towel right away. I definitely don't lose enough to detect an oil loss on the dip stick between changes. Sounds like your problem might be more severe.

[Kevin D]

79 cb750

Is this a dohc750 with ignition on left side? ? ?
I don't know the dohc at all but I'm studying the parts fiche and see gaskets (to hold oil in?)on the left side covers.

1979 CB750K'79 Limited Edition
1979 CB750K
•It was available in one color scheme: Candy Muse Red with Red
•The gas tank and side covers were 2-tone
•The wheels were black comstar
•There was a separate taillight assembly with the 1978 style lens
•The "10th ANNIVERSARY CB750K" side cover emblem was gold and green
•The engine was a 749cc DOHC 4-valve inline four cylinder linked to a 5-speed transmission
•The serial number began RC01-3000006

[Bob Wessner]

Oops, missed the '79 part. I guess this needs to be moved to Other Bikes, eh?

[6adan]

I have a 81 that I found oil there like you did,I just wiped it out and ran it,no problem so far.