Topic: oil leak, left side of engine, '76 cb550

[Hondawggie]

Hi all, had my '76 cb550F  out for an early evening ride.  Got home, parked it on the driveway, went to get the cover, came back -- steady drip of oil, almost a small stream, coming from the left side of the engine. 

It's too dark to do anything, all I could check was "did I forget to tighten the oil drain plug after changing the oil yesterday?"  Nope, it's tight and dry.

I looked at other posts and then on the web to see what lays behind the left engine case that covers the countershaft sprocket.  Here's what seems to be back there:

- oil pump
- output shaft where the countershaft sprocket mounts
- gear shift shaft

On the centerstand, the oil stopped dripping when my oil dipstick showed it was about 3/5 full of oil (it was completely full yesterday when I put in new oil).  A lot of the leaking oil is out there on the road, as the left side of my back tire was thoroughly wet with oil;  and the swingarm; and the chain guard; etc.  --- left side oil shower is what it looks like.

If this is an output shaft oil seal leak, it seems like I can change that seal with the motor still in the bike, no splitting the cases, etc.

Correct?

Or is it more likely a leak on the shift shaft's oil seal or the oil pump?
I hate it when it's dark like that and you want to dive right in and fix it.

[DaveBarbier]

With 550s a fairly common issue is a leak in the plug seal right in front of the countershaft due to having used, or currently using, an o-ring chain. You'll see where the leak comes from but just want to give you a heads up.

If there's wear in that seal and/or case that looks like chain rubbing, that's likely the reason.

[BomberMann650]

That much oil makes me think the oil pump split an o-ring.
It happened to me.
Even with the pump trapped in that cavity it still seeped out and made a mess.

[Hondawggie]

Got time to pull the shift lever off then pull the left side engine cover off.

Have a look at where my screw driver is pointing -- this little rubber seal I found 'drifted' down the shift shaft away from its round socket when I initially pulled the left engine cover (in this picture I've already pushed it back into the engine):



Upon further inspection, after cleaning off tons of the expected oil-caked-on-whatevers at the base of the shift shaft -- I found that this shift shaft seal needed to be pushed even further into its socket before it stopped moving inward.

My question:

- why would this shift shaft oil seal 'wander' out of its socket, down the shift shaft away from the engine case?


- is there some retaining clip missing or something whose job is to keep that shift shaft oil seal in place, and if so, how could it have come off, because the engine case and mounted shift lever would have stopped such a retaining clip from coming off the shaft?


After re-seating this 'wandering oil seal',  I of course wanted to test if I'd found the source of the leak.  So I:

- filled the crankcase back up with oil

- sat and watched the bike's exposed left engine side for a few minutes to see if the newly-replenished oil would leak out (it didn't)

- then turned on the engine, let it warm up and for a few minutes, let it run, with the countershaft sprocket off and the transmission in 1st gear so the output shaft would rotate while the engine was running (to check for output shaft seal leak -- there is no leak at the output shaft, it's bone-dry)


There is now zero oil leaking from the engine.  So the "wandering shift shaft oil seal" is the problem.

Do I need to replace a missing retainer clip and/or the shift shaft oil seal?

[DaveBarbier]

There's no clip there to hold the seal in place. My guess is with corrosion on the shaft it would grab the seal and spin it, eventually 'walking' it out of it's seat.

Others may have a better idea but if it were me, I'd replace the seal and clean the shaft with something like 600 grit wet-or-dry to remove any corrosion. Seal is cheap (get OEM) and it's an easy replacement.

[BomberMann650]

That's far out.

Literally 

+1 what dave said.

[Hondawggie]

Okay, thanks -- I'm buying the seal today--

any tips on extracting the old seal?  I've tried a few times and now that it's back in there, and me being pretty ham-handed with small parts, any advice?  I don't want to mar anything up with my 60-year old nervous system, which is usually amped up with caffeine

[BomberMann650]

+1 for dental pic

I buggered up my bike using the screw thread process.
Damn thing Started to drill into the shifter shaft.

[flybox1]

Anyone notice the wear marks on the plug in front of the front sprocket?
Someones been running a o-ring chain on your 550 

[BomberMann650]

Anyone notice the wear marks on the plug in front of the front sprocket?
Someones been running a o-ring chain on your 550 

530 standard chains an rub the puck too as I found out.

A Shim fixed that.

[Hondawggie]

Anyone notice the wear marks on the plug in front of the front sprocket?
Someones been running a o-ring chain on your 550 

Okay I was so focused on the oil leak issue I hadn't thought it through, but I did wonder why there was a 'bare spot' right there because the rest of it seems like hardened rubber, yet there was this area of bare where there was no rubber.

I have looked at the chain -- it is not an O-ring chain.  Now that I know about the clearance issue, I won't be installing one, thanks for noticing.

[Mooshie]

520 conversion for the chain.  Best thing I ever did for my CB550.  Wish I had listened and done this years ago.  Now I run an O ring chain and can actually keep up with newer bikes without having to shift 1000 times.
Also I changed out all the seals on the oil pump.  Super easy even for a girl  (hardest thing was finding one of the seals but got it from someone on the forum that had extras.  I forget his name but could find it if you need)

[BomberMann650]

520 conversion for the chain.  Best thing I ever did for my CB550.  Wish I had listened and done this years ago.  Now I run an O ring chain and can actually keep up with newer bikes without having to shift 1000 times.
Also I changed out all the seals on the oil pump.  Super easy even for a girl  (hardest thing was finding one of the seals but got it from someone on the forum that had extras.  I forget his name but could find it if you need)

Hey Mooshie - where did you get your 520 conversion sprockets from?!

Cognitomoto wants an arm and a leg for theirs.

[alacrity]

I have a 520 conversion done too. It's great for a lot of reasons.
Sprocket Specialists.
I think the guy there is named LANCE.

There's also a guy in so cal (a machinist) who does this... he made a smaller countershaft sprocket for me with the proper offset.
seventhgeardesigns@verizon.net

James Alfaro
7th Gear Designs
Optical Ignition Systems
Custom Sprockets
Custom Parts
Vintage Part reproductions

[alacrity]

Hi all, had my '76 cb550F  out for an early evening ride.  Got home, parked it on the driveway, went to get the cover, came back -- steady drip of oil, almost a small stream, coming from the left side of the engine. 

It's too dark to do anything, all I could check was "did I forget to tighten the oil drain plug after changing the oil yesterday?"  Nope, it's tight and dry.

I looked at other posts and then on the web to see what lays behind the left engine case that covers the countershaft sprocket.  Here's what seems to be back there:

- oil pump
- output shaft where the countershaft sprocket mounts
- gear shift shaft

On the centerstand, the oil stopped dripping when my oil dipstick showed it was about 3/5 full of oil (it was completely full yesterday when I put in new oil).  A lot of the leaking oil is out there on the road, as the left side of my back tire was thoroughly wet with oil;  and the swingarm; and the chain guard; etc.  --- left side oil shower is what it looks like.

If this is an output shaft oil seal leak, it seems like I can change that seal with the motor still in the bike, no splitting the cases, etc.

Correct?

Or is it more likely a leak on the shift shaft's oil seal or the oil pump?
I hate it when it's dark like that and you want to dive right in and fix it.

IF it's your shift shaft, and that seal hasn't ever been removed, you'd have to be Hulk to get it out with a dental tool.  I used two VERY short self tapping #6 sheet metal screws, get a couple turns of "purchase" on the seal. Apply a small vice grips to each screw head, put your feet on the engine case and use your core and low back muscles to start applying pressure - gradually increase steadily and it will come. If you just pull hard/fast, the screw will rip out.  If you try to go too deep, you'll drill into the soft aluminum of the seal platform.

THEN you gotta look really closely at the shaft. MANY of these have been galled, scarred or grooved right where the seal sits (and that's why). So now you put a new seal on and the f'er leaks again.  If you use sand paper to smooth it as someone suggested, you can end up easily with a flatted area that the oil will pass by under the seal face.  I had one that was grooved.  I removed it (from the other side of the engine -- see the service manual  -- it's pretty easy to get out, just remember where the springs go etc.  I then cleaned it really well and did a thin filler pass with jb weld.  THEN I cleaned that up after it cured and used hi grit sand paper to get it flat with the rest of the shaft. I used a machinist straight edge to get it close, and then a dial indicator to lock it in - kept doing very light sanding where needed till i was confident i had a true round shaft of the proper diameter.  Installed it, new seal, zero leaks 2 years a few thousand miles later.

[Mooshie]

520 conversion for the chain.  Best thing I ever did for my CB550.  Wish I had listened and done this years ago.  Now I run an O ring chain and can actually keep up with newer bikes without having to shift 1000 times.
Also I changed out all the seals on the oil pump.  Super easy even for a girl  (hardest thing was finding one of the seals but got it from someone on the forum that had extras.  I forget his name but could find it if you need)

Hey Mooshie - where did you get your 520 conversion sprockets from?!

Cognitomoto wants an arm and a leg for theirs.

Sprocket Specialists like Alacrity said.  Had to make a spacer for the front sprocket.  But that was not difficult (I didn't do it myself of course but had it machined for me).