Topic: oil leaks worth fixing?

[gmonkey]

My 550 is leaking oil from the head gasket area.  I pulled the engine out of the frame, got a complete gasket set from vesrah and was ready to tear into it when people here talked me out of it.  Planning on putting the engine back in the frame this week and finally got around to taking pictures of the leaks.  This look mild enough to leave be?  Is the oil on top of the intake a common thing as well?

[Gordon]

You already have the engine out of the frame, which is more than you needed to do to replace the top end gaskets and oil seals on a 550 anyway, so just go ahead and replace them, IMO.  The leaks aren't going to get any better. 

[Frankenkit]

+1.  Once it's out, you're already pretty far along, eh?  You'll thank yourself for this later.

[cameron]

I did my top end IN the frame... give yourself a weekend and do it!

c

[Fritz]

My advice would be to fight the impatience and bring the head and the cylinder bank to a machine shop, having them resurfaced.
This way, you will be sure that your new gaskets don't start leaking again.

[HondanutRider]

I believe your "leak" is a common problem of these small SOHC-4 engines.  At least with the CB350F it is a well known annoyance.  It really is just that - an "annoyance", as the leak is usually just a weep from around some of the oil passages and their o-ring seals.  It looks messy and un-Honda-like, but the oil loss is usually minimum doesn't cause any problem other than a messy appearance.

On my 1974 CB350F, it has this weep - but not all of the time.  The other day I was out to drop in at a vintage breakfast meet and was planning to stop for a gas refill along the way.  The gas station was about 10 miles away, and while I was about half of the way there I looked down and saw a brown oil streak running down both sides of the engine cases.  It wasn't too bad and didn't appear to be very copious or running regular.  I hadn't been "pushing it" to get to my destination (although on these machines if you are on the highway you really are, regardless) so I continued to the planned re-fuel.  There I checked the oil level (OK) and wiped the messy streaks clean.  Another 20 miles at the destination I only needed to wipe a bit of a film from a few places...ones I may have missed at the gas station.  After returning home after a nice non-stop ride, the engine was still spotless.

So you see, my leak/weep is an on-off thing.  Sometimes it's a quite noticeable, and other times it doesn't even seem to appear.  The bike is stock with just over 6,000 miles on it.  I'm not about to tear it apart over this annoyance.  It is after all, over 35 years old and deserves a bit of a pat/wipe once in a while, just to clean a tear or two.

[flybox1]

I've got this annoying head weep as well.  ~11k on my 350F. 
Gonna keep wiping my case clean until my pantlegs start collecting oil or when my oil is noticeably low between changes.

I change my oil to the tune of "While My C B Gently Weeps" 

[Gordon]

Another benefit to going ahead and replacing the gaskets, while you already have the engine out and have the new gaskets ready to go, is you can clean the carbon build-up off the pistons and combustion chamber, and you can check the condition of your rings and cam chain tensioner to see if they need replacing now or will need replacing in the near future.   

[TwoTired]

Go for it if you have confidence in your ability to deal with broken/stripped cylinder studs, various screws/bolts, can do helicoils, and can fit the cylinders over the pistons without breaking rings or piston ring lands, and know how to refit the cam cover without bending valve stems.
It's a good learning experience, if that has value to you.

Otherwise, just wipe off the engine from time to time.  If it weeps onto your pant legs, then it is time to go into it.  IMO

Engine out is not a factor for the 550. It can be done in the frame as easily as out of it, at a time of your choosing.

[Gordon]

Go for it if you have confidence in your ability to deal with broken/stripped cylinder studs, various screws/bolts, can do helicoils, and can fit the cylinders over the pistons without breaking rings or piston ring lands, and know how to refit the cam cover without bending valve stems.
It's a good learning experience, if that has value to you.

That's quite the "worst case scenario" there.  

Gmonkey,

I'm by no means an expert mechanic, and was even farther from that status when I first started working on these engines, and the only one of those listed possible bad things that I've ever had to deal with when replacing top end gaskets was a couple of stripped screw heads.  And that was only before I learned of the beauty that is a $25 impact driver. 

If you take your time and follow the manual you'll be fine.  And if for some reason one or more of those things does happen, they can all be fixed. 

A minor leak is certainly nothing to be too worried about, and if you're fine with just wiping it off when it builds up, then that's great.  You've heard some good opinions here, as well as some scare-tactics.  It's your decision to make. 

[TwoTired]

Everything I listed/mentioned are examples that have been posted previously.  Some mechanics are better than others.  You get to assess your own prowess/desire.  I can do things others can't and others can do things I can't.
It CAN be a straightforward fix.  Any mechanic with experience will tell you that rosy expectations will not guarantee there won't be worms inside the sealed can yet to be opened.

Best to open the can with eyes open and safety glasses, then trust to all the circumstances being in your favor.

Be prepared.  Not misguided by grand standing optimists.

I've also seen oil leak fixes that simply came back shortly after the "repair", btw.

Something else to add to the list of tragedies is a blocked oil line from a botched job, leading to a broken cam and head replacement due to galled cam bearing surfaces.  (also usually leaves you stranded)

Life is risk.  Don't let some else make you take a risk that does not feel right to you.  It's a risk/benefit assessment of what is best for your situation.

Murphy's laws were created with valid rationale, even if they don't ALL come true at the same time.

[Duke McDukiedook]

That doesn't look too bad, throw it back in.

People seem waaaay too quick to find a lame excuse to tear into their engines and regret it later.

If it is not leaking that much and you are not losing appreciable amounts of oil, LEAVE IT ALONE.

[Gordon]

I'm not misguiding anyone.  I'm giving my opinion and relating facts of my own previous experiences.  I'm not sorry that bothers you so much.

Perhaps your little vacation wasn't long enough.    

[TwoTired]

I'm not misguiding anyone.  

In your not so humble opinion...

Perhaps your little vacation wasn't long enough.    

Certainly wasn't long enough to please YOU!
I'm rather happy you are disappointed, King Gordon.

Any other personal attacks you'd care to add to this technical discussion?

[bistromath]

Aside from the philosophy discussion...

Not that this is definitive, but the 550s VERY OFTEN leak from the "pucks" -- the cylinder head sealing rubbers, of which there are 6. A leak at the pucks will look exactly like the photo you've got there. These can be replaced by removing the breather cover and cam cover. You don't even have to pull the cam out, and you don't have to pull the head off, so you save all that headache. It's a 1-hour job if you know what you're doing, probably an afternoon if you don't and you're careful. Use a very small amount of Threebond or Yamabond (NOT RTV!!!!!!) on the pucks, and you'll never have to worry about them leaking again. The only thing you have to really beware of is making sure the lifters are pulled back all the way with rubber bands or wire ties before putting the valve cover back on. There's a good post in the FAQ detailing the process. It might be worth getting that far in and checking it out, before you get elbow deep in the thing.

The other common top end leaks are:

- The rocker shaft plugs and covers, on either side of the valve cover. This doesn't look like the leak you have, but I suppose it could be. In this case, you'll notice a weeping drip coming from the bottom of those covers, the ones secured with a single large Philips head screw. If it's caused by rocker shaft wear (early 550s were susceptible, later ones less so) you'll need a new valve cover to fix it. You can tell by looking for "ovalling" of the rocker shaft bore. Otherwise there are four O-rings which when replaced should do the trick.

- The head gasket right at the oil passageways, located on the far left and right sides of the head gasket. There are a couple of small O-rings there that keep oil from that high-pressure oil passage from leaking into the head gasket, and sometimes they shrink and fail. You need to do a proper top-end job to fix this leak.

I don't think weeping head gasket leaks are that common on 550s, but I could be wrong. The pucks appear to be the culprit far more often.

[TwoTired]

I don't think weeping head gasket leaks are that common on 550s, but I could be wrong. The pucks appear to be the culprit far more often.

I don't know that the head gasket itself EVER leaks.  It's those oil passage orings at each end of the block that harden from heat and lose seal.  These are often misdiagnosed as a blown head gasket since it is on the same interface plane.

[i_m_jon]

If I might chime in. I went through the same decision on one of my 550's. After reading just a few posts here I decided changing the head gasket was the smart thing to do. After I removed the head, I came back here searching for an answer on something and came across some more info. Apparently, I would be a fool to change the head gasket and not the base gasket. So... I order my whole gasket set and when it arrives I also learn only a fool would remove and replace the cylinders and not re-ring the pistons. So... I get my new rings, get the cylinders honed and learn that I might as well rebuild the whole thing if it's apart. That bike is still apart and I can't tell you how much I wish I had just left a perfectly running 20k bike with a minor weep alone. My 2¢.

[Frankenkit]

Eh, I ended up working on replacing the head gasket, valve seals etc... but didn't touch the base gasket b/c it wasn't leaking.

I agree 100% with Twotired, however, on the point of being prepared for anything.  KNOW YOUR LIMITATIONS because with this old aluminum, what can go wrong, will certainly try to.

[zanorak]

Just a question to add here regarding the severity of oil leaks on these engines:

1972 CB500F - ALL of my cylinder fins are oily and I'm getting spatter all the way back to the rear shocks. Is this a "time to change the base/head gasket and orings" situation? It's leaving a halo wherever I park it but I'd rather not tear into the engine. Left side cam cover appears to weep, but not this much.

Thoughts? I've got about 300 miles on the bike since I bought it and rebuilt/rejetted the carbs. (sorry no pics! camera phone got wet... just imagine his photos with oil wet on all fins and collecting in a film on the case)

I put a half a quart of oil in it last week - so 1/2 quart per 300 miles?

[Ichiban 4]

Just wanted to add..that I'm in about the same situation as many others here..with my '77 550k.  It has only 9k miles on it..but weeps intermittently as shown in pics.  Seems to be worse..but not excessive..after riding for several hours..in hot weather..but never enough to really do much more than look messy.

Don't notice any real reduction in oil level in cases..between changes.  Have gotten into a sort of post-ride ritual of wiping down the fins with Q-tips after riding..sometimes.

I tend to agree with Lloyd..about letting well enough alone..unless something else worse starts showing-up (after all..this bike is now over 33 years old!).  I WAS going to do the head gasket replacement>>then cylinder base gasket>>then ring replacement thing (have all the parts on-hand..when that decision is actually made).   Showed the bike to a couple of mechanics/machinists..BOTH said: just ride it..till you actually need to tear into it.  That's good enough for me.

Think the tendency with a lot of us "armchair/keyboard" mechanics..is to offer advice..when we don't have to actually live with the consequences.  In this instance anyway..I'd go for what seems best/most practical for the situation.

Ichi

[Gordon]

Just a question to add here regarding the severity of oil leaks on these engines:

1972 CB500F - ALL of my cylinder fins are oily and I'm getting spatter all the way back to the rear shocks. Is this a "time to change the base/head gasket and orings" situation? It's leaving a halo wherever I park it but I'd rather not tear into the engine. Left side cam cover appears to weep, but not this much.

Thoughts? I've got about 300 miles on the bike since I bought it and rebuilt/rejetted the carbs. (sorry no pics! camera phone got wet... just imagine his photos with oil wet on all fins and collecting in a film on the case)

I put a half a quart of oil in it last week - so 1/2 quart per 300 miles?

That sounds like a lot of leakage.  Do you have to wear rain pants to keep your jeans from getting oil-soaked?  If you're fine with wiping up the leakage/splatter and you remember to check the oil level often, then you may be able to go for a long time like that, but if it were me I'd be doing the tear-down to replace the gaskets when I had the time. 

[seaweb11]

My K8 has a couple of fins worth of mild oil leak. 

I roll up some paper towel into a tiny ball and push it in between the fins at the front with a screwdriver.
I learned this trick 4 years ago on this forum   so don't blame me

After 4 years and many long distance rides........I change out the balls of paper a couple times a year. No mess.
It is so minimal it has never come to a point where I even worry about the amount of loss.

That being said, I don't know your bike or your mechanical skills so I will leave it at that.

[Hush]

I was going to tear my 650 apart this winter to fix some minor leaks but the cure might be worse than the pain so I'll put up with some minor oil bleed on the fins.

[Duke McDukiedook]

If I might chime in. I went through the same decision on one of my 550's. After reading just a few posts here I decided changing the head gasket was the smart thing to do. After I removed the head, I came back here searching for an answer on something and came across some more info. Apparently, I would be a fool to change the head gasket and not the base gasket. So... I order my whole gasket set and when it arrives I also learn only a fool would remove and replace the cylinders and not re-ring the pistons. So... I get my new rings, get the cylinders honed and learn that I might as well rebuild the whole thing if it's apart. That bike is still apart and I can't tell you how much I wish I had just left a perfectly running 20k bike with a minor weep alone. My 2¢.

Ha ha, sorry to laugh at you mate but that's one thing we try to stress on this forum.

If you have a minor oil leak don't pull your whole engine! Stuff it with paper towels or braided cotton rope.
Save the engine pull for a real problem or when it is time to bore out (after 100K or so.).

[zanorak]

Thanks for the input folks. I guess i'll try the rope and keep checking the oil!

This sucker is definitely coming out of the frame some day though, so I guess I'll plan on it then.

I should be able to handle the work, based on what I've read and seen online. Nothing special. (famous last words!!! HA!)