Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: peteuk on September 23, 2016, 02:48:52 PM
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I wonder if anyone has any ideas about an oil leak I have on my cb550f. It's not really noticeable in the garden just ticking over but on a ride out it gets boot and trouser leg splatteringly bad. I've tried the talcum powder thing to try and locate the source of the leak but I'm struggling. I've attached a pic to give you the general idea. There seems to be 2leaks, both at the left side of the engine (as you sit on the bike), one at the bottom of the fibs but the second i don't get cos the oil is collecting on top of the 6th final (from the top). This final is just ABOVE the join of the cases. I can't tell for the life of me where it's coming from. Any ideas, thoughts would be greatly appreciated.
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PS. That should be fins not fibs
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PS. Again. 6th fin not final..... Bloody predictive text
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Had A similar thing a lot of years ago now, take a look at the tacho seal
if that model has one (mine was on a 500)
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I had a similar problem when my crankcase breather was blocked, creating too much crankcase pressure and pushing oil out of anywhere it could. clean all the oil off and replace the crankcase breather hose.
if its not this, most likely the oil passage o rings between the head by the head gasket, these are known to leak on 550s.
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Usual oil leaks in order
(1) "O" ring in head gasket but usually only a small amount giving a "Mist"
(2) Sealing washer under the end cap retaining bracket(frequently missed out) NOTE SEALING
(3) Rubber pontefract cakes between rocker cover and head ( The heathens the other side of the water call them Pucks as they never heard of pontefract)
(4) Tacho drive seal or damaged housing
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Ahh I noticed when I Googled about it people talking about pucks. Didn't know what they were on about. Now I know. Does replacing the pontefract cakes mean taking the engine out of the frame. I think I may have to anyway as there is another leak right at the bottom where the fins start... ie below the first fin from the bottom
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By the way, are these pontefract cake seals the same thing as the oil passage o rings that philgesrty mentioned in an earlier reply
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No, the oil passage o rings are at head gasket level and base gasket level. You can strip down to base gasket level in the frame BUT READ THE MANUAL CAREFULLY
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I had an identical leak and it was the rubber head cover seal, new one from DS and good as new now.
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Note that even a single, small leak will spread out and make a major mess and genrally make the bike look like it is springing leaks everywhere. My wifes 250 nighthawk looses just enough oil to drop the level to the bottom of the dipstick from top every 1500 miles from an exhaust stud I sheared off and drilled a bit too far drilling it out. The resultant oil slick over my boots and the engine makes it look like it must be leaking from every gaskett and using a refinerys worth of oil.
Easiest thing to check is the cam end caps are sealed in the 3 correct points - eg the bolt as holds their brakett on the head, noting the alloy sealing washer etc are as per manual, and before now I have had oil peeing out of the O ring for the rocker spindle, or rather where the o ring should have been. After that the other thigs all require the head to come off ( appart from the pontefract cake things which only need the rocker cover off. I cannot say I have ever had one leak though, even though I re use them with a smear of heamatite on their seat before instalation.)
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Peter England you say you had an identical leak and it was the rubber head cover seal. Is that one of the 6 pontefract cake shape seals that another member mentioned? If not could you tell me what I should be looking for. Thanks
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Philgresty mentioned a blocked breather pipe. Not expecting much I removed the breather hose from the bottom of the airbox and just left it open to air, still connected at the other end to the top of the head. Took bike for a run, about half an hour, and guess what......no leaks. I don't know why as I have put all new parts in the airbox ie filter. The "element" is not available anymore so I made in as someone suggested out of scotchbrite, the green scouring pad stuff. Incidentally, when I bought the bike, thus hose was unattached to the airbox so I'm wondering if the previous owner had the same issue.
Anyway, any thoughts would be most welcome but as for now at least I come home with dry trousers and boots
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it's the long continuous rubber 'O' ring seal under the head cover, weird shaped thing
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Philgresty mentioned a blocked breather pipe. Not expecting much I removed the breather hose from the bottom of the airbox and just left it open to air, still connected at the other end to the top of the head. Took bike for a run, about half an hour, and guess what......no leaks. I don't know why as I have put all new parts in the airbox ie filter. The "element" is not available anymore so I made in as someone suggested out of scotchbrite, the green scouring pad stuff. Incidentally, when I bought the bike, thus hose was unattached to the airbox so I'm wondering if the previous owner had the same issue.
Anyway, any thoughts would be most welcome but as for now at least I come home with dry trousers and boots
glad my suggestion has seemed to do the trick for you, hopefully thats all it was, too much crankcase pressure.
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If the excess pressure problem went away when the breather pipe was disconnected from the airbox but still connected to the engine then it sounds as if the problem was (is) not with the pipe at all but the filter arrangement at the bottom of the airbox. Either the air cleaner joint pipe has a blockage or the breather element at the bottom of the airbox is clogged up solidly. As you say you have replaced the element with scotchbrite this shouldn't be the problem so it sounds more as if there is a blockage somewhere. Might be worth having a look at to see if there is a blockage anywhere before condemning the system