Topic: Leak at oil plug..?

[MetalHead550]

Workin on the 78 550k, suedo-Cafe racer today...a bug or two left.  I took it out for its maiden voyage today, since the charging problem(rectifier replacment) has been fixed.  Ran beautiful but while cruising at 60 or so I noticed my left peg felt slippery, left side of the bike, and my boot, covered in oil.  Traced it down and saw it was coming from behind the alternator cover.  I pulled the cover and saw oil puddled underneath the the little plug that sits directly beneath the rotor, the one with the little nipple on it.  I popped it out, I though way too easily, and went ahead and stuck a new o-ring on it.  Popped it back in and noticed that it seated mabey an 1/8 of an inch deeper than it was before I pulled it and it felt as though the o-ring may have seated itself in a little groove in that hole..in other words it felt right.  From what I can figure, theres an oil way behind that plug, and of course pressure from the pump would try to push it out, since all thats holding it in is compression from the o-ring.  It looks like the little nipple is supposed to sit against the outer edge of the alternator cover as it bolts to the crankcase, but as the plug is fully seated now, theres about an 1/8 of an inch gap between the nipple and the alternator cover.  So the question becomes(finally )...Is oil pressure supposed to push that plug out a bit so the nipple hits the alternator cover and the o-ring keeps it sealed?  Or am I missing a small part in that area that should keep it fully seated?  If this doesnt make sense I can post some pics.  At any rate I'm gonna pull the cover on my 75 and see for my self, but I thought I'd see what this post yeilds while I do it.  Thank fellas!

[MetalHead550]

Heres what I found out, in case anyone gives a damn, for future reference:  I pulled the cover on my 75 and the nipple on the plug was flush with alternator cover.  I was able to push it in further to create the same gap, like on the 78, so pressure must push it out against the cover and it seals that way.  I also noticed there is no gasket material in the area where the nipple meets the cover on the 78, but there is on the 75, plus theres an indintation in the gasket where the nipple presses against it.  The gasket on the 78 appears complete but the lack of that section may be what caused the plug to move just that little bit more out, and allowed it to leak.  However the new o-ring seems to be making a good seal for now but if it starts to leak I'll just add some gasket material with some RTV to that area and that should fix it...

[bryanj]

The hole that the plug is in is the main oil feed gallery to the mains, ends, etc from the oil filter so yes it has full pump pressure (regulated by the relief valve and yes it is held in by the generator cover. Usually it is a tight fit in the hole with a new "O" ring

[MetalHead550]

Good to know.  But, took it for a test run today and its stll leaking...not as bad, but bad enough!  I may have to drain the oil so I can see if perhaps there are some gouges in the cylinder behind that plug that is allowing oil past the o-ring.   Other thoughts:  Is it possible to have too much oil pressure(oil level is correct), mabey the relief valve is bad??  But then wouldnt the breather at the head relieve that?  Ill spread and sand some JB weld if I find any burrs in that cylinder..but I have a feeling its fine in there.  Any ideas on safely and intelligently "rigging" this if I have to?  Thanks.

[MetalHead550]

Ok guys, I had to bump this one.  Starting to get a bit frustrated w/ this leak...the last thing keeping it from being completely road-worthy!  You know how it feels.  I havnt had much time to mess with it lately but I drained the oil this morning and had a look in the oil way that that plug seals.  It's fine, like I suspected, so I went to the hardware store and matched up a brand new o-ring(the one I replaced it with the first time was from a varied collection of used and new so who knows).  Theres definitely a tight seal with the new o-ring, I ruined the first one when I tried to press the seal in and it shaved a bit of the o-ring off.  The second time I used a twisting motion while pushing in, by grabbing the nipple with a pair of pliers.  Nice and tight.....Still freakin leaks!!   Yes Im sure its coming from the alternator area cuz you can see it drip right out of the bottom of the alt. cover.  Problem is I cant see for sure if it is indeed coming from that plug or if its coming from the crank shaft bearing/seal and settling below the oil plug making it look like ITS leaking.   If you start the bike without the alternator cover, the oil pressure shoots that oil plug out, along with of course a bunch of oil (guess how I found out  )  Tonight I will try to rig up a temporary brace for that plug so I can start it and see exactly where its coming from.  While Im here though Id like to see what you guys can tell me about the oil pump.  Would it be possible for it to be building to much pressure behind that plug and causing it to leak?  If so, what would be the cause? 

BTW: why is there a plug there in the first place?  And how idiotic would it be for me(as a last resort) to cover the plug with JB weld if I find out for sure Im leaking there and some other internal/pump problem is not responsible.  Anyone??

[MetalHead550]

So 110 views and only one response?  Either Ive sufficiently stumped/confused or Im just generaly disliked.   Oh well!  One more try.

As some may have been waitng for me to figure out myself...Its not leaking at the plug.  I was able to take the alternator cover off and brace the plug like I planned and.....Its leaking from the crankshaft seal, behind the rotor  .  Kinda pissed.  I just recently got this damn thing back together after tearing it apart and splitting the cases to replace a gear on the countershaft!  I was very careful in putting the cases back together, including scraping all the factorty gasket maker off, prepping with laquer thinner, and applying a thin coat of high temp RTV.  So Im pretty confident its not leaking between the cases in that area.  It leaks only a small amount and I could see that it only seemed to leak significantly when I reved the motor up to around +6k rpm.  No leaking at an idle.

So to replace that seal, the cases have to come back apart right?  As it is, I cant see the exact nature of the leak since the rotor is in the way.  Id like to pull that rotor before I yank the motor(I assume it will have to be pulled anyway) to see whats happening and to make sure Im buying the correct replacement seal.  What do you guys suggest as a puller?  Will a gear puller do?  I'm still building up my tool collection as needed and Id like to get something I could use for other purposes besides just pulling this rotor.

Is this the correct seal? http://www.davidsilverspares.co.uk/cgi-bin/dss2-cgi/ProdSel.pl Note that is says left side.  Isnt it universal that the left side of the motor/bike relates to when youre sitting on it?  Dont wanna buy the seal for the wrong side.

Guess what Im doing this weekend?  I will conquer this machine!!!!  Damn-it.

[MetalHead550]

That link isnt working.  Go to DavidSilverSpares> Genuine spares> cb550k3> Crankshaft oil seal, left side.  Thanks. 

[Chris Liston]

Do you have any pics of this?  May help.  There are oil seal kits available on ebay that may have the correct seal you need.  Some pics would help to give your descriptions some more meaning. 

Sorry I don't have much else to add.

[MetalHead550]

Ok.  Pic 1 is where Im at.  The oil plug I thought was leaking is pointed out.  The rotor is pictured.  The leak is behind it.  I pulled the bolt that holds the rotor on its shaft and discovered larger diameter threads on the inner lip of the rotor itself.  Im assuming this is what the "rotor puller" threads too.  I'm still not aware of what this puller looks like or if something can be used in its place?  Perhaps I could fashion some type of slide hammer If I can figure out the size of those threads.  Pic 2:  Me taunting the oil leak and getting all in its face.  Dont think it worked.

[Killer Canary]

A small engine flywheel puller shouldn't set you back more than $10-$20.Maybe try a small motor repair shop.

[MetalHead550]

Cant help but take this one personally.  BYE.

[KB02]

Wish I could help on this one, but with my limited knowledge, it sounds like you;re on the right path to getting it solved. Did you use new seal when you rebuilt the engine?

-Bob

[Bodi]

You might get lucky and find that your rear axle has the same threads as the extractor threads in the rotor. Just be careful, with the taper on the axle end you might be only a few threads into the rotor and excessive torque may strip the axle threads. Apply a mederate torque and then tap the rotor with a hammer, this usually helps dislodge it.
The actual Honda official tool is fairly cheap, by the way - it's just a rod with a T handle and threads on one end. You might have to wait a bit but it's made of hardened steel and won't strip at least.
You might even find a bolt with those threads; I think it's a fine pitch metric thread though and those are pretty rare at retail.

[theunrulychef]

Just for my own curiosity & future reference (my neighbor's got a nice 550F that I've been giving advice on).  Is there normally any oil in the alternator chamber - like on the 750?  If so, couldn't it be that the alternator gasket is failing?

Thanks,
Jay in Philly

[bryanj]

OK just got to my desk again.
DO NOT try a three legged puller you will wreck the rotor
The special tool is available and different from 750 and 400 (its a hardened bolt that screws in and pushes onto the crank end)
Neither the seal nor the plug should leak at all
It is an engine out and bottom case off to the change the seals.
www.davidsilverspares.co.uk has genuine bottom end sets of gaskets/"O" rings at £10  and also does seal kits which 500 is same except for the blanking rubber plug in front of sprocket where clutch pushrod is on 500

It is unusual for a seal to leak unless its been fitted wrong--posible play in mains would start a leak and that is really an expensive job!!

[hcritz]

A word of caution...well a couple of words...Damn the English language is weird!<G>
If the rotor has magnets in it be cautious of striking it very hard...that can cause loss of magnetism...and reduced alt. output.
Or at least so I've been told!!!