Topic: Oil seal question

[twallace]

Hi fellas,

So I tracked down an oil leak to a seal 91207-374-000 just ahead of the front sprocket. It looks like the chain might have rubbed on it and damaged it. From what I read you have to split the engine case to replace it. Has anyone replaced this seal and did you have to split the case? It only leaks when the engine is running (warm). Any way I could stop the leaking temporarily until the end of summer when I can pull the engine apart? Oh...its on a 75 cb550.

[bollingball]

Did you figure out why it happened in the first place? O-ring chain by any chance?

[twallace]

Just picked the bike up last week so its all new to me...and I'm no bike mechanic but.....

I noticed immediately that the chain had a master link which I thought they didn't. I hadn't given it much thought until I went looking for this leak thinking it was the shifter seal and found a nice round gouge in the seal behind the chain. I assume the previous owner put the wrong chain on it and its worn through. I really wanted to ride the bike for the summer before taking it apart to restore it. The idea of spending the next couple months pulling the engine apart instead of riding is a bit upsetting.

[Hannibal Smith]

Don't let 'em drag you down...........

This rubber seal deal is as common as the clap, everyone has it.

This particular seal has a steel disc that is bonded/encapsulated by "rubber" and was designed to block off this bored hole from oil.

What happens, is that people swap chains eventually, and use an "O-ring" chain. The new chain is wider than Honda accounted for when "The Mini Skirt Mob" ( a critically acclaimed full feature film of 1968 depicting the trials and tribulations of mini-skirt clad busty starlets romping free in the California deserts seeking vengeance on the cowboys that did them wrong) was all the rage.

So, they swap chains, never realizing that the new fangled chain (that is now wider, but with the same part number so to speak) is taking the wood to the seal.

[bryanj]

If you want a temporary repair till you have time to remove the engine and do it right.

(1) remove chain and sprocket
(2) clean off ALL the oil and greae with a good solvent
(3) smear a film of epoxy (I use Araldite) over the damage
(4) leave for AT LEAST 24 hours before reassembling
(5) pray to your favourite deity and try out the bike

[bollingball]

Good idea from Bryanj but make sure not to put the fat chain back on. What is on there? Or does it all ready the correct chain on now.

[twallace]

Skirt Mob" ( a critically acclaimed full feature film of 1968 depicting the trials and tribulations of mini-skirt clad busty starlets romping free in the California deserts seeking vengeance on the cowboys that did them wrong)

2 years before I was born but sounds like my kind of movie!

The chain that's on there now is too wide so I'll have to replace it for sure. I understand what I want is a 530 100 NON O-ring chain right?

Good idea on the epoxy...I was thinking high temp silicone but epoxy might last longer. I'd really rather wait till fall to rip into it as I just paid my insurance in full and have been itching to ride since last year. Everything else on the bike (knocks on wood desk) is working fine so if I can fix this half assed and ride for the summer things would be good.

[Hannibal Smith]

Yep, that's the flick!

You can epoxy the seal and ride all summer no problem. And yes, you want a 530 non O-ring chain or run a 520 system, but you will have to change out the countershaft sprocket and the rear sprocket to boot (if you switch to 520). The 520 is a narrower chain, but the quickest fix is to grab another 530 chain.

[twallace]

Thanks Hannibal...my blood pressure is going down now. Found a chain at a local shop this morning. Its too long but comes with a master link so I assume all I have to do is grind off the right rivet and bobs my uncle.

The real question I have is...when the guy put a new chain on the bike and noticed that it pressed right up against the seal and nearly touched the case...why did he still put it on? I guess he may have taken it to a shop that didn't care and just slapped it together. Its all part of the sohc journey though!