Cam cover leak - Why?

[Anonymous]

At least, I think it is the cam cover. The bike is a 1980 GS550L, all stock equipment (except the mufflers). There are four, round chromed covers screwed onto the outside of the engine that I think are at the ends of the camshafts. Beneath them is a half-moon shaped rubber plug that (mostly) keeps oil in the engine case from leaking out (actually, it seems like kind of a dumb design to me, I mean why have a hole there at all?).

In the past I think all the covers have leaked a little oil at a very slow rate (like a drop or two a week), as I will occasionally have to clean oil off the engine cooling fins below them. But, I figured with the bike's age and all a little oozing and cleanup, adding a pint of oil every couple months, are small prices to pay.

Today was different. This morning the leftside rear cover began dribbling oil pretty steadily as it sat there idling, with maybe an ounce total lost. It also seemed to dribble more with the engine on than it did after I shut it off, though it took a while for it to stop completely. The only thing different I did today from my usual moring routine was that I let the bike idle for a bit longer than usual (about 10 minutes versus the usual 3).

Needless to say I didn't ride today, and when I get home tonight I'll pull the cover and look at the plug etc. Comments or suggestions from the collective here on what else I should be checking for, whether the plug can be repaired if it is the culprit, and any other thoughts would be appreciated. Also, is there something about running the bike at idle (rather than raving around on the highways) that could cause the oil pressure to build up high enough to cause a leak?

Thanks all in advance for any help and insight you can shed...

...Ross Potter

[robinjo]

Your plugs are probably dried out and rock hard, get some new ones.
Why they are there? Sort of a cushion for your cams.

[redliner1973]

The reason they are there is it is easier to bore the cam journals that way when the engine is manufactured.

[jimcor]

Owww, Ross, that's an air cooled engine! Watcha doing letting it idle that long? My 2 cents worth? You overheated it. That is what caused the increase in the leak.

Replace those old half moon plugs, you can still get them, I was just looking at the cylinder head on bike bandit today.

[Anonymous]

Yeah, I didn't mean to let it idle that long. I usually start it up, go inside to grab my lunch and jacket, kiss my wife, and two minutes later I'm backing down the driveway. Today, none of MY cylinders were hitting right (the bike is just fine) and I agree, it got hotter than normal (c-r-a-p). I'm hoping it didn't totally melt the little half-moon plug. In case it did, any suggestions for a temporary fix while I wait for the new part(s) (might as well replace all 4 at the same time) to arrive? I HATE not riding.

Be well...

...Ross

[jimcor]

Nah, it probably didn't melt the plug. Try some silicone sealer on the outside of the plug and the aluminum case. Probably won't stop it but might slow it down. PO did that to mine. I replaced them after a while.

[Anonymous]

Bugger. I looked at the plug tonight and in order to replace it I'd have to take off the entire cylinder top (meaning new gaskets and who knows what else when I get poking around in there). I am not up for that, at least not 'til winter downtime. For the near term I think it's going to be the high-temp silicone or the marine caulk. Still seems like a dumb design to me, I've half a mind to completely seal it with good old metal putty. Sigh. Oh well, I always wanted to be refered to as that "POS PO" when I sell the bike eventually. Thanks for the helpful words. Ride well...

...Ross

[jimcor]

It's not that big a deal... :roll: Keep repeating, "What a fun way to spend the afternoon!"

Please, don't seal it up with metal putty.

Propflux has it right. No other way to line bore the head than to have that half moon port.

The only thing you might consider with the head cover off is check the valve clearance, in fact if I was going to remove the cover I would definitely do this. Who knows you might end up keeping that bike for a long time. I bought mine as a 'between bikes ride', a temp...15 years ago.

Wasn't that an old, old Conway Twitty song? 15 years ago and I still...

OK I'm outta here.

[Detman101]

Plugs on ebay

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4561458744&category=35595

[bwringer]

CRC2 has 'em cheep.

http://www.crc2onlinecatalog.com/

http://www.crc2onlinecatalog.com/oil_seal_kits.htm#CAM%20END

$2.50 each.

[Anonymous]

So to recap, here's what I've decided. "Someday" (i.e., when timing, the bank account, and the urgent desire to ride) allow, I will pull the head cover and do it "correctly"; that is, I will replace all the gaskets at the same time (25 years old, could probably use it) and all 4 camshaft end plugs, and while I'm at it check the cam chain, tensioner, and valves. That's a bit more than a pleasant afternoon's work, but I figure it's yet another chance to learn more about the bike's inner functions while I'm in downtime mode anyway.

Meanwhile, I've caulked the camshafts and other leaky places with 400 degree silicone glue. So far it's worked great, no oil drippage at all anymore. And it is readily removable when I get around to the big head cover reno'. While I prefer to do things right, I hate not being on the bike when the weather's good, so I figure this is an acceptable compromise for now. Take care all, and thanks for the thoughts and advice. Be well...

...Ross

[mark m]

So to recap, here's what I've decided. "Someday" (i.e., when timing, the bank account, and the urgent desire to ride) allow, I will pull the head cover and do it "correctly"; that is, I will replace all the gaskets at the same time (25 years old, could probably use it) and all 4 camshaft end plugs, and while I'm at it check the cam chain, tensioner, and valves.

That really sounds a lot worse than it is. All you are looking at is a valve adjustment plus a check of the tensioner. Definitely not much more than an afternoon's work. The only gasket you will need is the valve cover gasket. It sounds like some new half moons would be worthwhile as well. Use a bit of RTV when you install them and you should have no more problems.

Mark

[jimcor]

Tygerman, you have a great summer! Glad you found a good fix. Save that metal putty for gas tank holes! On ahh, old Hondas or sompthin!

I really need to get out to your neck of the woods. A former California resident, but I didn't make it all the way up the coast before I went back to OH and KY.