Topic: Serious oil leak from the cylinder head side cover

[jerf]

Hi everyone,

I have a 1978 CB550K.  Over the last ~9mo I've been correcting a lot of problems that were neglected by the previous owners and getting the bike back to reliable use.  Over the holidays I did a top end rebuild and the bike is running better than it ever has has since I've owned it.

One of the problems from before the rebuild (aside from smoke and low compression) was some oil leaking on the side of the cylinders and engine case, and I figured that the top end rebuild stood a good chance of taking care of several problems at once since I was replacing the base gasket and head gasket in the process.  It seems to have, but I'm now observing an oil leak from the cylinder head side cover.  It's hard for me to say if this is a new problem or one that I didn't notice because of all of the other leaks.

I'm attaching a picture; I wiped the fins on the #1 cylinder side free of oil and then ran the bike for about 30 seconds, and you can see a small pool of oil forming.

I replaced the O-rings on the pins under that cover that (I believe) are where the oil is pushed from the oil passages out to lubricate the rockers.  I don't have the old ones to compare, but checking those rings with a caliper tells me that they are at least very close to spec at 6mmx3mm.  I can feel some gentle friction of the rings in the passages when I press the cover into place.

One other data point that puzzles me, if I switch the cover with the one from the other side of the engine, the leak remains by the #1 cylinder.  That feels like it would indicate a problem with the passage rather than the O-ring, but I don't see any scoring or other damage there.

I would appreciate any thoughts or experiences with tracking down the source of this problem.

Jeff

[newday777]

That's a fairly common leak problem on the 550 from what I've read

http://forums.sohc4.net/index.php?topic=112539.0

http://forums.sohc4.net/index.php?topic=81053.0

[newday777]

Dave500 should be along after he awakes today on the other side of the world, he's very familiar with the 500/550 motors.

[HondaMan]

A couple of 'generic' thoughts first, regarding this leak:
1. That side of the engine is where the oil comes directly from the oil pump to the head. The opposite side if the head has a little less oil pressure as the result. So, if the O-rings in your gasket set were slightly undersized (a common problem the last 4-5 years in my experience) then this combination can make it weep like that.
2. Oil type: are you using a non-detergent oil? If not, the oil is foaming, bet on it, especially that close to the pump. Also, avoid using 10w40 (or 10w-anything, for that matter) oil in this engine. Use diesel-rated oils at the least, for their low/non-detergent base, and 15w40 weight. The common Shell Rotella Diesel is decent oil at the lower end of the price spectrum. The Bel-Ray EXL Mineral is the best out there, currently, IMHO. After the engine breaks back in you can consider synthetics. but don't use them during break-in.
3. I have seen those 2 end covers swapped on these engines before: they are a LEFT and a RIGHT side part, with the center screw hole slightly off center. On the last one I rebuilt with these backward, it required a bunch of welding and file touchup, plus 2 new end covers, to get it right and stop the leak, as it damaged both the ends of the head and the covers(!).

Don't be tempted to use some sort of sealant to try to "seal" those ports, rather use different, even slightly thicker, O-rings if needed. Sealant will work its way into the oil passage and can then ruin the rocker and shaft at that side.

I seem to recall (but its been almost a year since the last one) that it was considerably harder to install the end covers when the new O-rings were installed during assembly, and I had to oil them to get them slid into place. What I don't recall at the moment is: whether that was because I used thicker O-rings (like 5.8 x 3.2) or if they were the ones that came in my Vesrah kit. I have had lots of problems with the NE gasket kits, like improperly-located holes in the head gasket, poor fit of the cylinder base gasket, and too-thin O-rings, so I quit using those.

[bryanj]

Should be a soft alloy washer between the side cover bracket and cam cover, without a good one you get a leak

[jerf]

Thanks everyone - I'll check the brackets and make sure I didn't swap them.  I'll also get some new oil in there and make sure it's the right viscosity, I'm due for a post-rebuild change anyway.  I also have some O-rings coming in a couple of incremental steps up and we'll see if a little extra sealing pressure does the trick.

I'll report back in a few days, thank you for all of your input.

-Jeff

[Little_Phil]

3. I have seen those 2 end covers swapped on these engines before: they are a LEFT and a RIGHT side part, with the center screw hole slightly off center. On the last one I rebuilt with these backward, it required a bunch of welding and file touchup, plus 2 new end covers, to get it right and stop the leak, as it damaged both the ends of the head and the covers(!).

To clarify it's not the end covers that are left/right its the right angle bracket with the thread that the covers screw to. These brackets have a washer above and below. The lower one is soft ally and that does the sealing.

[dave500]

make sure those brackets dont have any burrs around the bolt hole,i use a copper washer top and bottom on those bolts.

[HondaMan]

3. I have seen those 2 end covers swapped on these engines before: they are a LEFT and a RIGHT side part, with the center screw hole slightly off center. On the last one I rebuilt with these backward, it required a bunch of welding and file touchup, plus 2 new end covers, to get it right and stop the leak, as it damaged both the ends of the head and the covers(!).

To clarify it's not the end covers that are left/right its the right angle bracket with the thread that the covers screw to. These brackets have a washer above and below. The lower one is soft ally and that does the sealing.

Aye! It is the bracket that is L or R.
Thanks for the correction, Phil.

[Tracksnblades1]

Diesel Oil vs Gas Oil ?

             🤔


https://www.hotshotsecret.com/diesel-vs-gas-engine-oils/

[Tracksnblades1]

🤔

https://www.motortrend.com/how-to/1906-whats-inside-that-bottle-of-oil-really-does-make-a-difference/#:~:text=To%20improve%20the%20performance%20of,oil%20contains%20high%20detergent%20concentrations.

[dave500]

can of worms just opened?any of the older dino oil type diesel oils are fine in these engines,dont use the type recommended for DPF filters and so on,they have lesser zinc and other additives that prevent metal contact but would otherwise foul an expensive truck DPF filter etc,ive driven trucks most my life and all the new green emission engines are detuned no torque rise to speak of and most uninspiring!you floor the pedal under load and the exhaust note doesent even change for 10 seconds,nor do rpm rise much in that time,do that with an old say mack maxidyne 237 or 285 or cat or cummins etc and youll grunt away instantly.

[bryanj]

True Dave, everything now is fly by wire and chip controlled to keep the emissions down

[dave500]

#$%* emissions,i wanna see rolling coal!

[bryanj]

Im stil averaging 400km per shift, but only do 4 a week now im 70

[dave500]

whoa im 64 and just backing off now!new kids cant drive other than some half fangled automatic,struggle to run a dual range syncromesh,give me floppy roadranger anyday!sorry for the side step everyone!

[newday777]

Diesel Oil vs Gas Oil ?

             🤔


https://www.hotshotsecret.com/diesel-vs-gas-engine-oils/

 

Why did you post these Oil poser posts with no explanation??

[TwoTired]

#$%* emissions,i wanna see rolling coal!

..from behind you, or in front of you?

Just asking…😁

[Tracksnblades1]

#$%* emissions,i wanna see rolling coal!

What’s your all time favorite Big Cube Coal Roller…?

[dave500]

well off topic now but dont really have a favourite,i like old 70s/80s Macks,theres an old Peterbuilt 359 i think i see from time time getting around,we didnt get many here.

[HondaMan]

#$%* emissions,i wanna see rolling coal!

What’s your all time favorite Big Cube Coal Roller…?

Cummins 2400 cubic inch V24 with 4 turbos, one on each corner, 2450 bHP at 4750 RPM.
We used them for fracking engines, driving triplex pumps thru my microprocessor-controlled 9-speed mining power transmissions (before computers were even small enough to fit INTO a car...).

The engines under the hood of the trucks that hauled these monsters around were also Cummins, but only made 550 HP at 3800 RPM with 1 turbo.

[Tracksnblades1]

#$%* emissions,i wanna see rolling coal!

What’s your all time favorite Big Cube Coal Roller…?

Cummins 2400 cubic inch V24 with 4 turbos, one on each corner, 2450 bHP at 4750 RPM.
We used them for fracking engines, driving triplex pumps thru my microprocessor-controlled 9-speed mining power transmissions (before computers were even small enough to fit INTO a car...).

The engines under the hood of the trucks that hauled these monsters around were also Cummins, but only made 550 HP at 3800 RPM with 1 turbo.

Sounds like some very special high rpm applications, especially for the big girl.

I have a major crush on the Cummins KTA 19 known also as KTA1150 older ones, the older ones were governored for 2100 high idle. Newer ones closer to 1800.

Caterpillar 3406 are really good ones with great torque rise. I like the 3406E best. All these old girls are low rpm girls. Might as well shift at or even before 1800 instead of ringing it’s neck. it pulls harder down low anyway.

Cummins N14stc and N14E are torch bearers. Most of these are 2300 high idle no load.  You can do more with the E models more hp, But a properly tuned and timed STC has great torque rise from 1250-1750 rpm. Around 1550-1580 she’ll break drive line parts trying to maintain it.

Dave500 will be more current with the new bigger girls, but the newer engines trends are slow and slower dances to increase efficiency especially Volvo.

Big CATs like C18 always did turn slow compared to the all the different Cummins 855 models.
IHC had the highest revving big engine I’ve ever been around called a DVT800. With 800 cubes big bore short stroke turned around 2850 fuel pincher, sounding like a Detroit 2cyl at 2850. Didn’t do well in OTR truck or Agricultural apps at 2850 had a lot of picture windows on down shift overrevs.  Ran forever at 2100 in off-road apps.