Topic: cb500 oil pump leaking, maybe. Now with cylinder gouging.

[DavePhipps]

When my son took the left crankcase cover off a lot of oil came dribbling out. It seems to be confined to the oil pump area but I can't pinpoint the exact location. As a precaution I'm ordering the Orings for the pump.
Can anything else in this area leak.
Also I broke the bit on my impact driver trying to remove the screws from the oil pump. I'm going to drill through the screw heads but can't remember what size bit I've used in the past. Someone raided my tools and made off with many of them including the mystery size bit I used to use. So suggestion on bit sizes?

[goldarrow]

Oil pump seals or shift shaft seal.

[DavePhipps]

Shift shaft seal is fine so that leaves the oil pump Orings?
hmmm... saying Orings make me want onion rings, YUMMY!

[goldarrow]

4 orings for oil pumps. 1 for pump to case, 1 for pump cover, and 2 for dowels. 

[billingstitan]

You'll want this one for the oring under the oil pump cover: The o-ring for the oil pump cover is sized 46x2mm. Honda's part no is 91305426003 - it's for a goldwing - but it's the only one available.

My advice - don't use aftermarket on this part - I did, and it ended up .1" too thick and starved my bottom end resulting in a spun bearing - that part referenced above works perfectly and is available at most dealers and definitely online.

[goldarrow]

You'll want this one for the oring under the oil pump cover: The o-ring for the oil pump cover is sized 46x2mm. Honda's part no is 91305426003 - it's for a goldwing - but it's the only one available.

My advice - don't use aftermarket on this part - I did, and it ended up .1" too thick and starved my bottom end resulting in a spun bearing - that part referenced above works perfectly and is available at most dealers and definitely online.

Honda oring is great.  Aftermarket orings work just fine.  Don't blame on those orings if you starved your top end.

[Bodi]

.1" too big? That's 2.54mm! I don't see any way you can blame an O-ring for that. If that part number is, in fact, a 46x2 O-ring - although metric sizes can be difficult to find especially in singles, any one the same size must be the right fit. The material... who knows, but it will fit properly.

[DavePhipps]

How did I mss all these replies?
I know the Oring under the cover of the pump isn't leaking, however there seems to be a boatload everywhere else in the area behind the pump. Once the bike actually starts I'm going to run it with the case cover off and see where it's all coming from. Don't worry I'll clean the area spotlessly first.

[billingstitan]

@bodi & goldenarrow - with all due respect - I'm not "blaming" anything - it was my mistake that's for *(#@ing sure  I thought I found the answer, failed to do more research on the forum for differing opinions, and suffered the consequences.

That said - there is absolutely no question the slightly thicker aftermarket o-ring starved the bottom-end on my 1977 CB550 by dropping oil pressure, which resulted in a spun bearing.

I got pointed in this direction by ill-informed advice from a well-meaning forum post, so it's important to point out the catastrophic result of an "almost right" sized o-ring under the 550K oil pump cover to other members to ensure they have accurate information.

Whether folks heed my hard-earned, expensive lesson-learned or not is their own choice. I do feel obligated to the community to share it, however.

Bottom-line: if the o-ring under the oil pump cover is even slightly too thick, it impacts the operation of the oil pump by pushing the cover further away from the pump's rotor and dropping the oil pressure.

Perhaps this is unique to 1977-78 CB550K's - I don't know, these are the bikes I run so these are the bikes I have experience with.

I DO know beyond question that what caused the issue with mine was a slightly thicker aftermarket o-ring.

As far as "blaming" ... I've *#%(ed up more stuff on my bikes than I can remember over three decades of riding, so I'm sure not concerned about blame. I don't know anyone who has spent any time working on bikes that doesn't have similar stories.

I am concerned that folks get straight info. I don't submit or comment on posts unless I'm certain about what I'm talking about - mostly, I ask questions - but I do know my way around a bike.

 Again - submitted with all due respect.

[bryanj]

I posted the size a very long time ago and have used both aftermarket and genuine Honda after my generic supplier would only sell in 100 lots. I can only guess that the 46 x 2 you were supplied was a unified "Equivalent" and slightly thicker which i am afraid to say some suppliers do way to regularly as they mostly sell for hydraulic purposes and consider it not to matter

[billingstitan]

That sounds plausible, bryanj -- I wouldn't doubt the commercial ones were simply not as exact or consistent in the sizing specification as Honda's, as it did seem folks on here had run those aftermarket o-rings with no issues ... and prob still do.

I bought a 100 lot o-rings from a commercial supplier/part number recommended from the forum, and after the whole debacle happened (i.e. my engine blew) -- I ran across a post with that alternative OEM o-ring (Honda part 9130542600) and got one for the oil pump in the replacement engine, along with a few spares.

There was a noticeable difference in size considering they were almost the exact same specifications 'on paper.'

And, full disclosure, I was a dumb*** because I noticed my oil light flickering here and there after changing the oring, but my bike had been down for about six weeks while I did a slew of other maintenance: bearings, forks, tires, brakes, bars, etc., etc., etc. -- and I just didn't immediately connect the dots. 

I thought I had a bad sensor or poor connection as there was not a noticeable change in the engine sound. I didn't ride the bike a lot - but all it took was one 15 mile 'test run' to hammer the bearings into oil pan glitter.

In any case - I swapped the o-rings on the oil pump before I took the damaged engine out (it still runs), and lo and behold the oil light flicker immediately resolved itself. So I've no question that was the issue.

Fortunately, I did find a great replacement engine at a great price and was back on the road in a couple weeks ... but it still ended up costing me $700 w/ the shipping, so that was an expensive o-ring, lol 

But, hey, at least I found an engine! 

[Lostboy Steve]

When my son took the left crankcase cover off a lot of oil came dribbling out. It seems to be confined to the oil pump area but I can't pinpoint the exact location. As a precaution I'm ordering the Orings for the pump.
Can anything else in this area leak.
Also I broke the bit on my impact driver trying to remove the screws from the oil pump. I'm going to drill through the screw heads but can't remember what size bit I've used in the past. Someone raided my tools and made off with many of them including the mystery size bit I used to use. So suggestion on bit sizes?

Snap-on makes a very large bit. Phillips 3. Part Number: fps32e. Its the bit I use for just about everything. As far as the oil-pump goes. I had the same problem on my 550k. If the oil pumps are the same (not sure) its most likely the pump cover o-ring. I did all the seals and o-rings while I was in there.

[DavePhipps]

Ordering the OEM orings this weekend, thanks for the part #. That makes it much easier.
Will be getting the #3 bit also.
Now back to sorting wiring on this bike.
 

[goldarrow]

Ordering the OEM orings this weekend, thanks for the part #. That makes it much easier.
Will be getting the #3 bit also.
Now back to sorting wiring on this bike.

Might want to have drill bits and left hand thread easy out handy, just in case.....they come in handy when needed....just saying...

[DavePhipps]

Looks like easy out is the option, or drill to the countersunk area and carefully remove the screwhead. I've now broken my impact driver bit ad chewed up the screw heads... oh joy.
Does anyone know what length these are, and it there a stainless allen bolt that can be substituted? I'm really sick of screws on bikes.
I almost forgot to mention this fun little bit. The oil light comes on a very low RPMs. This is a new behavior. The bike sat for almost a year due to perdonal illness, injury, and lack of funds. When parked it leaked but the oil light never cam on at low RPMs.

[billingstitan]

Oh s**t, brother ... proceed carefully, that's exactly what mine did before it spun a bearing. I have a couple oil pumps for 77 CB550s I picked up when troubleshooting the issue so if you're needing one let me know. Not sure about the cross-compatibility with years.

[DavePhipps]

I'm not riding it right now anyway. Not until I get all the leaks and other assorted bits fixed. I have my trusty FZR to get me around.
I'm going to have the engine apart down to the crankcases ans oil pump off. Anything specific I should look for other than oil pump rotor clearance and plugged oil jets/passages?
Thanks for the pump offer. I'll keep that in mind if mine turns out to be bad.

[goldarrow]

Take your time with the drill bit and left hand thread. It will come out without damage the thread.

[DavePhipps]

DOes anyone know what size drill bit and extractor I'll need for this? These screws aren't listed in the Fiche anywhere.

[billingstitan]

Glad you've got another ride - that makes the down time much more bearable.

I'm no expert on those oil pumps (he says, bolting in a replacement engine  ) -- but they seem relatively bullet-proof. The manual lists the specs.

You can see if you're getting oil up top by just pulling a valve adjustment cover on each side of the engine and turning it over with the engine run switch turned to 'off'.

You should see be able to see the oil pumping into the area. On the 77 CB550 the oil wells up from around the end of each side of the camshaft. Note - I'm not saying to pull the whole valve cover, just the round tappet hole covers. You can peek in there and see it flowing.

I'm sure you already double checked the oil level to ensure it didn't leak to a critically low level.

The only other suggestion I'd have is to pull the oil pan and check the oil screen and the tube to ensure those are clean and free of obstructions.

Sorry about the stripped nuts - we've all been there    Those left hand drills have worked for me every time - just go easy. And watch those oil pan bolts, those SOBs strip easily as well (ask me how I know)

 

[billingstitan]

Based on info I got from the forum, it looks like those screws are M6 x 20, 20mm full length, approx 16mm of actual thread. Sounds like you can replace with a stainless allen head bolt - here's where I got the info: http://archives.sohc4.net/index.php?topic=8614.0

[brooze72]

Don't forget the oil sender switch, mine also started coming on at low rpm, removing & cleaning did squat, new switch was the answer.

[DavePhipps]

Thanks billingstan, and brooze do you mean the oil pressure switch? Heck I'm not sure if that's the right name for it, but it screws into the top of the oil pump.

[billingstitan]

Yup - that's the one -

[Bodi]

Not blaming anyone... more of a poorly worded poke at your dimensioning: I think you must have meant 0.01" oversize, at the most.
A 0.1" larger cord would be over twice as thick as the original.

[Storyman]

My 76 CB550F has clearly been slowly leaking from the oil pump cover. Impossible to find any info on the correct "skinny" o-ring under the cover pretty much anywhere but here! The dealer & everyone said it's was the larger one (which I'm guessing goes under the pump against the crankcase), and which I ordered (grrr). I can't tell you how happy I am to read that there's another honda that uses the same o-ring. I will order up one of those ASAP. I guess I will hold on to that other o-ring in case I spring another leak in the future. I noted that it's possible to change the o-ring without losing more than a dixie cup full of oil. Obviously keep it clean in there. Luckily my impact wrench did the trick, too. I used a rubber mallet, and it seemed to work fine. I thought less shock the better.

[billingstitan]

@bodi - gotcha, no problem, brother. And, me, f'n up numbers? Yup, that sounds about right.   

Pops was my math teacher in high school, and I still managed to get a "D" in algebra 

@storyman - that part number is great -- these forums are the same place I tracked it down.

I'm running it on two CB550's and it finally resolved that sneaky oil cover leak, and have had no issues since.

That oil cover leak is a b**ch -- replaced all the oil pump o-rings on the fiche, shifter seal, and the seal behind sprocket - and each time it seemed to resolve that gear-shifter leak.

But what was actually happening in removing the side-cover, it'd dump the build-up of oil from the the slow leak from the oil pump cover, and then it'd take a few weeks to build up again from the leaking oil pump cover.

I'd think I'd have everything finally resolved, then boom, another pair of tennies ruined 

Glad you got it squared away! SOHC strikes again.

[DavePhipps]

O-rings are in. Tomorrow I get into the oil pump. I'll update with pics.

[DavePhipps]

OK got the pump off. I just drilled through the screws that I couldn't get out with the impact driver.

Son had my tablet so fast forward to fixed.

Gade 8 hex bolts on the cover

I then decide to check thing out under the head, and found something scary.

It seems that there was a piston clip missing. NOw the piston pin gouged cylinder #3. So either I forgot it during last years rebuild or there is one in my crankcase.

Time to overbore or Ebay some cylinders.

[DavePhipps]

A rough estimate is .5mm. Not good. On the bright side this gives me more time to clean up, polish, and paint everything else on the bike.
Checking ebay now.

[billingstitan]

That bah-lows - sorry, bro - these GD bikes are heartbreakers sometimes ...

[goldarrow]

Beauty of the 40 yr old Beast. 

[DavePhipps]

Beauty of the 40 yr old Beast.

Speaking of beauty I'm doing a quick polish of the crankcase covers. If I can't make it run I'll work on making it look better till I get replacement cylinders. Will post a pic when I can finally pry my tablet away from my son.

[billingstitan]

Ha ha - reminds of my friend - good plan!

I convinced my buddy to buy a 74 Suzuki Titan (T-500) - and old two-stroke streetbike - from a guy that used it as a ranch bike.

Didn't know it at the time, but unlike these Honda's, parts are pretty much impossible to find.

He's been working on it for the past two and a half years (taking frequent breaks to curse my hide for ever putting the idea in his head), and finally got everything together and got it running just this spring.

He took the same approach - just detailing it while he was waiting to track down parts. Well, after 2 1/2 years, that bike is SO cherry at this point - repainted petrol tank, oil-injection tank, etc. Every bit of aluminum polished, pipes shined to a gloss - He loves it now - and it is a looker, man. You NEVER see those old two strokers around anymore.

Keep at man - these 'ol b*****s always come together if you're patient enough 

[DavePhipps]

Keep at man - these 'ol b*****s always come together if you're patient enough 

I'll keep at it. I may not have money for parts nut I've got lots of patience. Speaking of parts and keeping myself busy. Here's the left crankcase cover. It still needs a final pass

Also where can I find just one cylinder sleeve?

[DavePhipps]

Waiting to hear back from 2 ebay sellers. I want to make sure the bores are the correct size. There's a lot of 550 stuff being confused with 500 on ebay.

[DavePhipps]

This is for the 500. Why would I need to bore the sleeve?

[bryanj]

But you said it was a 550 pump leaking

[DavePhipps]

Sorry, I'm still getting this a bit mixed up. Still recovering from a concussion. It is a 500 though.