Topic: Leak from Crankcase? Remedy?

[Y00B@99]

    Hi everyone! I'm fairly new to the forum, mostly been using it like an index for some of the questions Ive had. I recently purchased a 78 CB550 as my first bike, and been digging it so far. A few days ago I was riding it to work when oil leaking from the left side, started leaking onto the exhausts(I think) , making smoke. Luckily, I wasn't too far from work, and parked it. I am relatively new to motor maintenance, but am willing to learn. I would like to fix the issue myself if possible. But I definitely need some pointers.
     From what I can tell, the leak is coming from the left side crankcase. I removed the cover today, and didn't see a gasket for the cover, but i'm unfamiliar enough with this that I cant determine if that's the culprit. I have some photos below, for reference. If anyone has an idea of what could be wrong. The bike still turns over, and idles, but the leak persists.

Photo: https://scontent-lax3-1.xx.fbcdn.net/v/t1.6435-9/240057214_157836249823025_2342124817715724038_n.jpg?_nc_cat=110&ccb=1-5&_nc_sid=730e14&_nc_ohc=-UsF3Noh0TEAX_0XFeJ&_nc_ht=scontent-lax3-1.xx&oh=b5c9958b59114ade653f3accfca97da8&oe=6146DA19

[newday777]

Welcome aboard YOOB@99

That cover has no gasket so the leak is behind it or above that side cover that covers the chain and front sprocket. You'll have to run it without the cover to investigate after cleaning it up to see where your leak it at.
The leak is most likely from either the output shaft seal behind the chain sprocket(I don't remember if the 550 has a chain oiler screw that might have been opened too far) or possibly the oring on the starter and coming out the starter tub(tub full of oil under the starter cover??), or it might be the rubber grommet that seals the stator wires allowing oil to be forced out.

Reply back here what you find.

Where are you located?

https://www.southernhonda.com/--xpartsstream#/Honda_Powersports/CB550KA_(78)_550_FOUR_K%2c_JPN%2c_VIN%23_CB550K-2100001_TO_CB550K-2122082/LEFT_CRANKCASE_COVER_%2b_STARTING_MOTOR_%2b_OIL_PUMP/0f12de96-474a-4fbe-a2ee-8ba2cda5f653/a18a1471-27a6-4462-87e9-e76ce9f082fb/y

[flatlander]

correct, there is no gasket under that cover.
oil is dripping down from the top of the cover which wouldn't be the case if it originates from the parts that are actually under the cover. also there's oil on the top of the crank case, and coming from the fins of the cylinder.

while driving the wind blows the oil around and makes it harder to trace its source. i'd thoroughly clean the whole lot, then run the engine stationary to warm it up and see where oil first appears. you may need to rev it a bit to get pressure up. 
if you're worried about overheating it if you need to run it for a longer time while standing, you can point a fan at it.

this should help narrow down the area(s) of the leak(s). further, you can clean it off again and blow some baby powder on the suspicious areas, then do the same as above - on the powder it'll be more easy to trace to the actual source.

[Y00B@99]

     I'll get some baby powder and give the bike a run, and check it out.
Heres some photos of when I took the cover off yesterday, without running it: 1. https://scontent-lax3-1.xx.fbcdn.net/v/t1.6435-9/240127107_158183379788312_3265893257317125662_n.jpg?_nc_cat=109&ccb=1-5&_nc_sid=730e14&_nc_ohc=QCAkWGrBWDgAX_Pc9OK&_nc_ht=scontent-lax3-1.xx&oh=75f53d3abe56189e86f2342f5ad57cb4&oe=61479CDA
2. https://scontent-lax3-1.xx.fbcdn.net/v/t1.6435-9/240000780_158183466454970_8781589227960694960_n.jpg?_nc_cat=110&ccb=1-5&_nc_sid=730e14&_nc_ohc=MWOYKWgdOfUAX8dZ-cr&_nc_ht=scontent-lax3-1.xx&oh=dfe4c7085ea01fa5936e5dcc90422d65&oe=614AA3EE

     I'll post some more photos soon, after I get the bike warmed up. California, it get pretty hot down here. It was 89 degrees at 7am in the morning.

[carnivorous chicken]

oil is dripping down from the top of the cover which wouldn't be the case if it originates from the parts that are actually under the cover. also there's oil on the top of the crank case, and coming from the fins of the cylinder.

This. If it were anything under the cover, it wouldn't be all over the top.

[Y00B@99]

    Okay, I ran the bike for a few minutes, till the oil got too low, and the bike stalled. From the baby powder it looks like the oil is leaking from the right side; on the lower fins. Heres a photo: 1. https://scontent-lax3-1.xx.fbcdn.net/v/t1.6435-9/240224366_158380979768552_2594084754840063690_n.jpg?_nc_cat=110&ccb=1-5&_nc_sid=730e14&_nc_ohc=jzhkSAIv8VAAX_vrIkU&_nc_oc=AQl64Q0QSi4eicz2Q9FaHzdiS6VR5qWV9PnY7n2pKVYKzwpZ3rUyT57lBfCUG1bzfw5Sx5LpTQHj6Mj2cj5k715s&tn=Wf3X-z4SiO7JHfij&_nc_ht=scontent-lax3-1.xx&oh=ea12e0165acf47450eff7f1e81d1018d&oe=61493A72
2. https://scontent-lax3-1.xx.fbcdn.net/v/t1.6435-9/239907791_158381723101811_2505301286354987815_n.jpg?_nc_cat=109&ccb=1-5&_nc_sid=730e14&_nc_ohc=044Tk2wNihIAX9NbOrn&_nc_ht=scontent-lax3-1.xx&oh=e2730e31cdad96b67a98b31e2de7aa0c&oe=614A4102

    What should the next steps be to fix the leak? Do you guys suspect it's a gasket problem?

[Don R]

 If it stalled from low oil, that's a serious issue. Look for the clean spot above the dirty oil stains. Also check the crankcase vent hose to be sure it's open so it can allow excess blowby pressure to escape the engine.

[Y00B@99]

     Can the crank case vent hose get clogged, and cause pressure to build up?

[ekpent]

 This is some that came out of a 750 breather hose that runs off a valve cover and made an oily mess out an oil tank. Looked like paper wasp or some other critter so the answer would be yes its possible. Not saying its your problem but it can happen.

[Y00B@99]

    Thanks. I'll take a look at mine as well.

[bryanj]

That is either a very bad headgasket leak or leaking from the end cap on the cam cover. You need to track it down better

[Y00B@99]

    How would you suggest I go about it? Should I take apart the front end to check the gaskets and seals?

[flatlander]

do as i described earlier. before pulling things apart you need to first locate where the leak comes from.
i'm with bryan as to the most likely source but you do need to narrow it down first.

[Y00B@99]

Okay. Will do. I'll let you guys know what I find soon. Thanks!

[flatlander]

Okay. Will do. I'll let you guys know what I find soon. Thanks!

don't forget to start by cleaning off the existing oil spill. otherwise it'll be impossible to see where it actually comes from.
the idea is that you run it until you get the first traces of oil leakage.

[HondaMan]

It kinda looks like the oil is coming from the head joint. This can happen if the rubber pucks under the camshaft were replaced with the wrong (too thin) ones, which is a common error by mechanics who don't know that there are 3 different thicknesses of these pucks out there. They all ahve the same outisde diamter, and pretty often the wrong ones get used in these engines. They make a nasty mess.

Before running, always make sure the oil is up to the mark on the dipstick. Low oil can seize an engine quickly, making for an expensive repair!

[newday777]

It kinda looks like the oil is coming from the head joint. This can happen if the rubber pucks under the camshaft were replaced with the wrong (too thin) ones, which is a common error by mechanics who don't know that there are 3 different thicknesses of these pucks out there.

Where do you get the correct thickness pucks? Link? Honda only?

[TwoTired]

Are there made or can you make rubber shims for the pucks?

Used to be able to buy neoprene in sheets.

Just a thought….

Cheers!

[Y00B@99]

    Hi. After some looking. I found a little crack in maybe the head gasket? Let me know your thoughts. 
Photo: https://scontent-lax3-1.xx.fbcdn.net/v/t1.6435-9/240993349_163611535912163_8135281049611852813_n.jpg?_nc_cat=104&ccb=1-5&_nc_sid=730e14&_nc_ohc=DzYXhEIfhKcAX-Kq8Af&_nc_ht=scontent-lax3-1.xx&oh=9a21c7f27eb54d3b6b3104a14d59b773&oe=61538BA7

Kind Regards
   

[bryanj]

I think you will find that is a pre formed notch to allow the use of a pry tool to get head off

[HondaMan]

It kinda looks like the oil is coming from the head joint. This can happen if the rubber pucks under the camshaft were replaced with the wrong (too thin) ones, which is a common error by mechanics who don't know that there are 3 different thicknesses of these pucks out there.

Where do you get the correct thickness pucks? Link? Honda only?

Get them from PartsNmore or CB750 Supply online. The 750 and 500/550 use the same ones.

[Y00B@99]

    If I replace the pucks, should just go ahead and replace the gaskets and rings as well? From what I can tell the leak is coming from the top, but gets obscured as the oil drips top other parts of the engine. Any luck with aftermarket gasket sets?

[flatlander]

to replace the puck you only need to lift off the rocker cover. the head itself stays in place, so there's no need to disturb head/base gaskets. and why would you replace rings if you don't have problems with compression or smoke from the exhaust, they have nothing to do with your leak?
did you check at the end caps of the rocker cover, if there's no oil leaking? there's a bolt that holds the little bracket that they attach to, that needs sealing washers which some PO may have forgotten.

[Y00B@99]

    @flatlander.
    Just trying to understand the parts as I get along. Not too familiar with these engines, but doing my best to learn. Would you recommend any good online schematics of the CB550 engine? I'll take a look at the rocker cover.
    Kind regards.

[RAFster122s]

South Sound Honda of Olympia WA as southsoundhonda.com
Has online parts diagram which show exploded views for parts ordering.
They have very good prices as well.