Topic: 400f oil dripping from points cover

[thundershild007]

Can anyone shed a bit of light on this leak.I was thinking main crank shaft seal. I can't see if there is a oring for the advancer assembly or what the advancer  attaches to on my diagrams?
Any info most appreciated.

[bjbuchanan]

The shaft has a little fat o-ring seal on it, could be the leak source but the usual culprit is the big seal that involves splitting the cases to swap.

Hopefully it is just the advancer shaft o-ring but...

[ttr400]

No advancer shaft or O-ring on a CB400F, only the crank oil seal. Cases need to be split to replace.

Kevin

[MoMo]

Remove the point plate and advancer assembly then the source should be visible, as Kevin said if it is the seal the cases have to be split.  However, I've never seen one leak, another possibility is case damage from a long ago laydown or improper assembly if the cases were split.  Good luck with it...Larry

[jonda500]

I had this problem with my cb500f engine that I got from the wreckers. It was so bad my brake pedal was always dangerously slippery, so I installed a brass drain pipe with a rubber tube that went down next to the battery breather tube and driped the oil away from the brake pedal at least! Over time however, the leak slowed right down to an acceptable seep

[thundershild007]

Thanks for the info guy's, at this stage it isn't bad but the engine was professionally rebuilt for the previous owner when the bike was restored and it has only done about 3000klm's since. I have just finished replacing the head gasket which was leaking oil and did the base gasket while I was at it.
snapped a ring on the way back in just to keep it interesting.
after a couple of good heat cycles I re torqued the head and it is not leaking now. I did my timing which wasn't easy, oil and filter and balanced the carbs
and it's running great.
First carb balance with the $130 "carbalance" brand tool of ebay very happy well worth the bucks.

[MoMo]

3000 km equal less than 2000 miles right?  No way should there be any leaks after a rebuild other than maybe seepage from a head gasket that could need to be retorqued...Larry