Topic: 550/4 CHAIN REPLACEMENT CAUTIONS

[43and countiing]

My 1975 550/4 started to drip a bit of oil. I had changed the sprocket and replaced the chain with a heavy duty "0 ring" style, that was supposedly ok for the bike. After a great deal of frustration thinking it was the oil pan or a crack, I did a serious cleanup inside the cover and looked behind the sprocket and chain. Well, Honda built these with a lot of specific tolerances, and the space between the chain and transmission housing is very tight. Given the natural side to side movement of a chain on the sprocket, coupled with the additional width of any o-ring chain (this one was clearly a full side of a chain wider) and the recipe for disaster struck, as the chain wore a small hole in a cover over the transmission, directly between the sprocket and transmission wall, out of sight. I have filled the hole with JB Weld, and had to replace the modern o-ring chain with an original plain chain, which is measurably narrower. I can deal with the extra maintenance needs of this chain.
Go figure.

[Johnie]

Sorry to hear what happened. To bad you did not come here sooner. O or X ring chains on 550's is a routine topic on this board...they do not mix. The JB Weld has been known to be a fix as long as you caught it early. Good luck and let us know how you come out.

[754]

They have never been ok on those bikes, unless you have an offset front sprocket.

[tlbranth]

I think an x-ring is worth whatever you have to do to make it work. Funjimmy modified his front sprocket to work with x-ring. You might query him.

[Airborne 82nd]

Lots of post on this. Read through the FAQ. The 750 uses a huge 60 o-ring chain They kicked the chain out 10 mm to make up for that wide chain (77-78) They don't need it now with the newer chains. You may give the PJ 1 blue label chain lube a try they sell it at my local Honda shop stays on best I have tried in the last 60 years.

[seanbarney41]

+1 on the PJ1 blue label...don't bother with Bel Ray ultra clean.  I think that stuff actually ruins your chain faster.

[dave500]

white lithium spray can grease.

[DaveBarbier]

Yeah, this is a common problem. I had a lot of wear on my 550 case and seal plug directly in front of the sprocket. Luckily it didn’t go all the way through. You’d think people would hear the case getting worn away...

[Deltarider]

Is my assumption correct an O-ring is no problem on the CB500? Decades ago I had one. I was not impressed, but I can't remember it damaged anything. Next time when the sprocket cover is of, I'll have a close look.

[Bankerdanny]

If you want to use an o-ring chain on a 500/550 you need to change from the stock 530 to a narrower 520. But this is expensive since it requires a custom front sprocket that costs about $70.

[Deltarider]

We've never established whether it concerns all models: K? F? 500? It could be that only the CB550 is vulnerable and not the 500, maybe only the 'F' and not the 'K'. Hence my question.

[Bankerdanny]

The 500 has some internal differences in the clutch and gearbox vs the 550, so maybe there is more room for a wider chain.

To the best of my knowledge the differences between the 550 F/K models are purely cosmetic and some changes in carbs and jetting.

The 750F has different primary and transmission gearing than the K, but you can use an O-ring chain on either of the 750 versions without issues.

[dave500]

the 500 fouls equally,some chains are worse than others I guess,and how much movement is on the sprocket and shaft.

[my name is nobody]

Some claim to run an o ring on a 750 with no problems, some unable. Countershaft bearing widths may have something to do with it. I have found
that not all o ring chains are the same width (overall) even though the pitch is the same. One brand o ring chain different than another..I'd never run one on my stock 550. jmo..

[Deltarider]

What I would like to know: how serious is it? At least two Dutch dealers specialized in SOHC Four sell both standard as well as O-ring chains to CB500/550 owners. I had one, a very long time ago but I can't remember it rubbed the case. Next time I remove the sprocket cover, I'll let you know. It's like with the primary chain. Everybody keeps on repeating it eats into the oil gallery. Well, mine has done 135.000 kms so it's safe to assume the chain has left his marks but... so far no problem. Given that I've never heard of a catastrophy there, I volunteer to test it till the end. The pics I've seen of cases that were scarred by the secundary drive chain, well, what can I say, it's not nice ofcourse, but did it lead to severe problems? Again: how serious is it? Facts please, no opinions.

[DaveBarbier]

What kind of evidence will you accept man? Apparently not all the pictures of cases being worn away and some which haven’t been caught early enough to cause an oil leak like the OP, apparently.

[754]

 There has been plenty of pics of chain wearing into the 550s on here.
 I don't en have a 500 or 550 and have noticed this.
 One thing to remember, it's not just chain width that you worry about,
It's side play of chain on the sprocket,  that is another mm  or 1.5mm.
 And can be more when both wear.

[Deltarider]

This is what OP said:

as the chain wore a small hole in a cover over the transmission, directly between the sprocket and transmission wall, out of sight.

It's not clear to me what cover he means. There's a cover over the chain and front sprocket inside the sprocket cover (no. 2 in https://www.cmsnl.com/honda-cb550-four-1975-cb550k0-usa_model465/partslist/E++04.html). That's known to break (it did on mine) but that won't cause any oil leak. Did I miss something?

[calj737]

This is what OP said:

as the chain wore a small hole in a cover over the transmission, directly between the sprocket and transmission wall, out of sight.

It's not clear to me what cover he means. There's a cover over the chain and front sprocket inside the sprocket cover (no. 2 in https://www.cmsnl.com/honda-cb550-four-1975-cb550k0-usa_model465/partslist/E++04.html). That's known to break (it did on mine) but that won't cause any oil leak. Did I miss something?

He's talking about the sprocket cover, and the hole being worn into the leading edge of the chain/lower case as is typical with chain damage. He describes it as the "trans" cover, but its the lower case. Since he accurately explained its drive chain damage due to sprocket/chain play, I am unclear how anyone is confused with where/what he's describing. Its a known issue for 500/550/750 models. Is it present on EVERY bike? No, but like many things, there is ample evidence to support this as a systemic problem.

[Little_Phil]

The pics I've seen of cases that were scarred by the secundary drive chain, well, what can I say, it's not nice ofcourse, but did it lead to severe problems? Again: how serious is it? Facts please, no opinions.

Dave's post sums it up. The picture shows the case with no pushpod seal (CB500) or transmission end seal (CB550). It is clear in his picture that the arc of the rubbed area passes these. The seals (particularly the 550) often stick out a little). It is metal backed rubber and has rubbed through this rubber and metal in 43s case above. Up to you whether you think this is serious.

[bryanj]

The 500 has a pushrod seal that is not under oil pressure the 550 has a blanking plug that is under oil pressure, they both wear with O ring chain but the 550 shows more oil leak

[DaveBarbier]

The 500 has a pushrod seal that is not under oil pressure the 550 has a blanking plug that is under oil pressure, they both wear with O ring chain but the 550 shows more oil leak

You sure it’s under pressure? I didn’t think it was. There’s no gallery in the case for it where the seal goes.

[dave500]

The 500 has a pushrod seal that is not under oil pressure the 550 has a blanking plug that is under oil pressure, they both wear with O ring chain but the 550 shows more oil leak

the 550 blank seal isn't under pressure,its the counter shaft that has an oil pump to carry oil up to it,its not really pressurized either as it just drips out between the gears,that pump isn't engine driven its turned by the counter shaft,when stationary it doesn't pump.

[43and countiing]

This photo is virtually the exact situation I have after using an "o-ring" chain. My loss of the rubber cover was an exact semi-circle, like a "half-moon". Not sure how anyone could think oil loss is not serious, but we all have our standards I guess. that oil leaked out of the exterior case and blew all over my rear tire as I drove. I take it seriously. and I greatly appreciate the feedback in this forum. While this may be an example of being a "do it yourselfer", I really wonder how many dealer mechanics would have know this.
Hindsight is great..I still have my original chain, and it is incredibly narrower than either of the o-ring chains I bought. And the point made above about chain slide side to side is dead on...any slack in the chain (as required) allows the chain to need even more clearance. I'm not sure if o-ring chains existed in 1975, but if so , I sure wish Honda had mentioned it in the owners manual.

[Deltarider]

43, scarred cases I've seen plenty, the oil leak you developped there, actually is the first I have seen. Thanks for warning it can be that dangerous. Dave, thanks for that excellent photo.