Oil leak oil plug left side engine

[Erwin83]

Hi everyone.

I'm having difficulties beating an oil leak on my CB350f.
I've already replaced the O-ring (#13) with a OEM Honda one (6 euro for an O-ring  ).
Cleaned the hell out the area where the plug (#3) goes, took the plug out and cleaned again. Added a tiny smear of gasket to the plug on the outside of the O-ring... Still leaking. And not a weep, but quite big drops. Too much to ride around with.

The area above the plug is dry as bone, so I have no reason to assume it would be the crank oil seal.
There are also no visible oil traces from the oil pump area (on the side stand, it would drip to the lowest point on the casing, which is where I am leaking oil)

Am I missing something? Do you have any suggestions?

[mike the bike]

It needs to be tapped in to place.  Obviously not too hard, but firmly.

[Bryanj]

You did fit it with the pin facing outwards?  and the generator cover needs to be fitted to hold it in.

[Erwin83]

It needs to be tapped in to place.  Obviously not too hard, but firmly.

Hmm, ok. I just pressed it in with my thumb. It is snug though. The O-ring definately seems to be compressed.
I'll try to give it a tap, see if it goes any deeper.

You did fit it with the pin facing outwards?  and the generator cover needs to be fitted to hold it in.

Yes, pin facing outwards. Cover mounted. I've not yet gone to the lenghts of making a plate to keep the plug in and be able to run the engine without the cover.

[Erwin83]

OK, I was actually able to gently tap the plug in about a millimetre further.
I'll give her another warm up later today and see if there's still a leak. Fingers crossed 

[Bryanj]

If the cover is on it will push back out till it touches the cover, thats what the pin is for.
If it leaks either the bore is damaged or the O ring got damaged

[Erwin83]

Yeah, it didn’t make any difference. Bummer.
I’m a bit out of ideas now.
How about making a little spacer so the plug is kept in deeper?

[Bryanj]

Should need it unless the plug, O ring or bore is damaged

[Trigger]

First off you must find if it is the bung leaking. I have never had one leak before after a engine rebuild, new 0'ring, a smear of red rubber grease and push in.

I would clean the whole area down with clutch and brake cleaner including under the engine, cover the area in talc power and you should see any wetness straight away.

6 euro is crazy for that 0'ring, i get them in trade packs for about 60p each 

[TrickyMicky]

Just a quick query from a numbnuts, never having taken this part of the motor apart before, but I was under the impression that the alternators actually ran 'wet', and occasionally the seal where the wiring exits would sometimes leak. Am I out of touch?

[Bryanj]

"Wet" alternator only on 750, smaller ones are dry and have a seal behind the rotor

[Erwin83]

I’ll go for the talk powder test. Although it looks bone dry in the area above the plug (direction crankshaft seal), I guess you never know.
I can safely run the engine without the alternator, as long as I unplug the fieldcoil, right?

Oh, and I’ll make some plate to prevent the plug from plopping out...

[Bryanj]

Nope, if you run the engine with the alternator cover off that plug will disapear to the darkest, dingiest corner of your garage never to be seen again and a large puddle of oil appear under the engine

[TrickyMicky]

"Wet" alternator only on 750, smaller ones are dry and have a seal behind the rotor

  Y'know, I always regard it as a good day when you can honestly say that you've learned something new. My age is above the national speed limit, and only ever having performed mechanical 1st Aid as opposed to full surgery, I never knew about the wet/dry facts re. the alternators. Your knowledge also meant that I learnt a 2nd new fact in one day regarding the differing current directions from a single coil. It is due to the good people such as yourself that make this forum so readable. Thank you everybody. Michael.
   PS. If you want to go into a fit of the screaming ab-dabs, I will admit to all and sundry that I still time my ignition using a fag paper (not mine!) trapped between the points!

[Bryanj]

Always used paper and a pencil down the plug hole for Triumphs with a mag. Im 68 and still learning