Topic: 1975 Cb550 oil filter cover leak

[JDrider]

I just recently purchased this motorcycle and I was curious if it’s leaking because it wasn’t bolted on correctly. Please look at the photo and let me know if it should be put on better. What does that tab need to be inside the slot? Thanks.

[bryanj]

Yes the tab should be in the slot, get a NEW HONDA filter kit, dearer than pattern ones but the O rings are the right size.
When you replace the filter first you fit to the bolt a spring then a hardened thin waser then the filter

[JDrider]

So are you saying it doesn’t look right?
Should I assume the PO didn’t install correctly?

[scunny]

Take it off and see what you have. You will have to drain the oil first.

[JDrider]

I was hoping to avoid removing completely

[bryanj]

If its leaking it needs to be removed and inspected, you dont need to drain the oil and will not loose that much

[JDrider]

Oh ok, thanks

[Bodi]

Only what oil is in the filter plus a bit from the gallery is lost. Inspect the case face, the o-ring, and its groove. The groove has to be pretty clean. Check the cover for damage, overtightening damages them and little cracks leak oil..
It should be tightened until the cover seats on the case then just a bit more, not cranked down heavily. Original bolts have a 10mm head to suggest not much torque is needed.

[newday777]

Only what oil is in the filter plus a bit from the gallery is lost. Inspect the case face, the o-ring, and its groove. The groove has to be pretty clean. Check the cover for damage, overtightening damages them and little cracks leak oil..
It should be tightened until the cover seats on the case then just a bit more, not cranked down heavily.

 Original bolts have a 10mm head to suggest not much torque is needed.

12mm not 10mm.

[PeWe]

If unknown last oil change, a good idea to change oil with filter.
There are Honda  o-rings if you have another filter.

[newday777]

I just recently purchased this motorcycle and I was curious if it’s leaking because it wasn’t bolted on correctly. Please look at the photo and let me know if it should be put on better. What does that tab need to be inside the slot? Thanks.

If the leak is coming from the filter, the previous owner probably didn't change the orings which flattenout over time(2, 1 large diameter, #22 1 small diameter, #21 on the bolt). The valve tappet caps have orings that also need replacement that flatten out.
Use 6 point sockets on the oil filter bolt and the tappet caps to help preserve the bolt if a monkey over tightened them from flattened orings.
As has already been said, replace the orings when you change the oil and filter, get the Honda orings as the aftermarket orings usually are the wrong size on the bolt(too large) and don't go in the housing as they should.
And don't leave the washer, #13 stuck to the filter(get a new one in case the PO lost it and didn't replace it.
The tab holds the filter housing in place so it doesn't spin as you tighten and loosen the filter bolt.

Clean the grunge off the motor and confirm where the leak is coming from, as it could be coming down from the hockey pucks in the head.

https://www.southsoundhonda.com/--xpartsstream#/Honda_Powersports/CB550KA_(76)_550_FOUR%2c_JPN%2c_VIN%23_CB550K-1230001/CRANKCASE_%2b_OIL_FILTER/f77665b3-598c-4e35-ad4b-7a873770e3e5/eb6e68e2-c206-4a75-b2df-f26b6f8e1536/y

[JDrider]

Thank you guys!

[PeWe]

I guess the filter is same as CB750 and lots of other bikes. Marked 401.
My oil cover groove for o-ring does not leave much o-ring over the edge.
Tighten cover a little bit too hard is not good either, o-ring gives up.

I have searched for a harder model possible to tighten harder.
I bought a 50 pack of o-rings, NBR 89x4.5mm hardness 70 the only choice I found if I remember correctly.
O-rings with most filters too thin.

I have never had a leak between bolt and filter cover. Replace that o-ring each 3rd- 5th change or so. If several years old replace.

[bryanj]

Correct, it fits all the sohc fours plus all the 4 cylinder wings and a few non Hondas.
401 is a "pattern" filter number and some of the makes do supply undersize O rings that leak, if you are not doing a lot of miles, the genuine filter kit is the easiest, but not cheapest, way to cure the problem

[dave500]

give that main bolt a light few raps first,and as stated use a six point socket,these can be a real bear to remove neatly if theyve been too tight and left for years.

[carnivorous chicken]

give that main bolt a light few raps first,and as stated use a six point socket,these can be a real bear to remove neatly if theyve been too tight and left for years.

And there is no need to crank it down too hard when you get it back on there, just enough to seal it up.