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

[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.