Topic: Non-running CB550 - Danger signs?

[toomanybikes]

Later today I'm going to look at a non-running '78 CB550. Assuming it's a non-runner, are there any tell tale danger signs that may be unique to SOHCs / CB550s?

I've resurrected multiple VJMs (several non-runners) and know how to check for all the standard things (compression, clutch, headset bearings, sprocket wear, etc,.). This would be my first SOHC Honda, so I figured you experts might be able to provide some guidance. I checked the FAQ and couldn't find a good summary, but feel free to send a link if I missed something.

I don't know if I'll be able to test start it or if the pistons will be dry/stuck from sitting. I assume the carbs will be clogged.

I'll bring a charged battery to test lights & signals, but won't be able to test the charging system if it's not running.

Thanks

[calj737]

About the biggest thing to know (obviously aside from compression, etc...) is whether any PO ran an O-ring chain. To determine any damage will require removal of left shift cover to examine the front sprocket area. The width of the chain can eat a hole in the case right there and it’s behind a cover, so inspection is awkward visually.

After that, just about anything else is easily remedied.

[dave500]

the o ring chain wont kill it,youll be doing a rebuild more or less anyway?

[toomanybikes]

I'll check the current chain and try to look under the cover. Probably won't be able to pull the cover off during buying inspection since it appears to have the original JIS bolts. For all I know it might still have the original chain.

Good to know about oring chains if I need to replace this one.

[dave500]

if aint o ring don't sweat it!

[toomanybikes]

Thanks again for the help. I pulled the trigger and will post pics once she's cleaned up.

Bike only had 10k miles on it, so could have been the original chain.

[Kelly E]

I pulled the stock chain from the last two bikes I did, a 74' 550K with 18k and a 75' 400F with 17k.

[Erny]

Does it mean I cannot run O ring chain on 550K1? That's what I actually plan to do...

[dave500]

itll rub the casing,they are wider than a standard type,o ring chains wernt invented when these bikes were built.

[Deltarider]

Does it mean I cannot run O ring chain on 550K1? That's what I actually plan to do...

A few days ago I asked the German site (both the CB500 and CB550 sections) what experience they have with various sealed chains and I will also ask the British, French and Italian site. I hope to report more on this in the foreseeable future. Sofar a German CB500 owner claims he has good results with a DID-VX.
I quote him in translation:

... My old chain had a 25mm width which had milled a bit of the casing. The DID-ZVMX has 24,9mm width and would also rub.

Another CB500 owner had claimed he has good result with this ZVMX type. [explanation Deltarider]

...That's why I went for the DID-VX which has a width of only 23,3mm and this chain runs just free. One can even get a 2/10 feeler gauge in between, when chain is fully pushed towards the casing.

I'd like to add the following remarks.
There could be a difference in clearances between the CB500 and CB550 models and even between the various CB550 models, K and F.
Both the CB500 and CB550 models can develop considerable play at the rear wheel sprocket carrier which will may have an effect on the chain's trajectory.

[toomanybikes]

Update - Here's a pic after a quick wash. Thankfully, it's led a very sheltered life. Don't yet know what needs fixing to make it a runner.

[Erny]

now start to wonder - stock chain was 530 or 520?

I'm sure it was written somewhere, but cannot find it now.
DID does heavy duty 530 NZ, that shall have 22.5mm width

[uksparky]

Your 550 looks like it was taken care of and looks dam nice.... i got my 550 non running  11,000 miles.. first thing was cleaning the jets in the carbs and replacing float needle seats and rubber gaskets, did it without pulling the carbs.... after i got it running about five hundred miles later the O rings started to leak oil at the head gasket........ at that point i decided to pull the motor, split the cases and replace all the gaskets/ seals ...

[DaveBarbier]

Does it mean I cannot run O ring chain on 550K1? That's what I actually plan to do...

No, unfortunately. Search for pictures of the cases being eaten away. Could switch to an o-ring 520 chain. I’m only assuming that is thin enough to clear the cases.

[DaveBarbier]

Update - Here's a pic after a quick wash. Thankfully, it's led a very sheltered life. Don't yet know what needs fixing to make it a runner.

 Very nice! Since we were talking about chains, what does this one have on it? Have you removed the sprocket cover?

[toomanybikes]

@DaveBarbier - From visual inspection and mileage, I assume the chain is the original chain, or at least definitely not o-ring.

I have not yet looked under the chain cover, but will do that once I can get those JIS bolts out without mangling them. Most bikes I switch over to allen or hex heads, but this one is so original I may keep the original fasteners.

[TwoTired]

Does it mean I cannot run O ring chain on 550K1? That's what I actually plan to do...

A stock 530 chain is narrower than an oring chain because of the added orings.  You need to make mods to the front sprocket to offset it, to account for the oring extra width, as it is very close to the engine case.  Wear and or wobble of the front sprocket will gouge the case.
A 520 oring chain will work, but of course, then needs 520 front and rear sprockets.

Cheers,

[Erny]

Wish I knew this issue before I ordered new 530 sprockets - now too late  .

So the only chance would be to find good quality non-O ring chain equal to stock specs and do regular frequent maintenance.
Or, buy new 520 sprockets (if exists for CB550) and chain. Pretty costly.

When I removed chain (non-O ring) I noticed that case has traces of chaing rubbing it... now I understand. Attached pic.

Was thinking to insert washed under sprocket, but this is not the way due to sprocket locking system...

[DaveBarbier]

Wish I knew this issue before I ordered new 530 sprockets - now too late  .

So the only chance would be to find good quality non-O ring chain equal to stock specs and do regular frequent maintenance.
Or, buy new 520 sprockets (if exists for CB550) and chain. Pretty costly.

When I removed chain (non-O ring) I noticed that case has traces of chaing rubbing it... now I understand. Attached pic.

Was thinking to insert washed under sprocket, but this is not the way due to sprocket locking system...

If it doesn’t leak I wouldn’t mess with it. Looks like a PO put an o-ring chain on and caught it before it became an issue. Also, regular chains are totally fine. Some say they’re better because they have less rolling resistance than o-ring chains. Both require maintenance, both stretch.

[dave500]

im happy with standard type chains they last fine.

[TwoTired]

Wish I knew this issue before I ordered new 530 sprockets - now too late  .

So the only chance would be to find good quality non-O ring chain equal to stock specs and do regular frequent maintenance.
Or, buy new 520 sprockets (if exists for CB550) and chain. Pretty costly.

When I removed chain (non-O ring) I noticed that case has traces of chaing rubbing it... now I understand. Attached pic.

Was thinking to insert washed under sprocket, but this is not the way due to sprocket locking system...

My 74 Cb550 has those marks from a trial of a 530 oring chain promoted by the Honda dealer.

The front sprocket usually has a flare from base mount to tooth.  If you machine one side flat to tooth plane, and place a washer on the opposite side the thickness of what was machined off, then mount sprocket with flare and washer towards the motor, you regain the clearance with such an offset sprocket.

I've had good service with standard chains, so I haven't done this offset front sprocket technique.  Others have, though.  Bob, I think.  Saw pictures not long ago on this forum.

Cheers,

[Stev-o]

I have not yet looked under the chain cover, but will do that once I can get those JIS bolts out without mangling them.

Be sure to use an impact driver with preferably JIS bits.

[bryanj]

Thats a repainted K3 550 and the biggest problem is i will be 99% certain the pilot jets will be blocked and they are a press in fit, search PD carbs for info.
The exhausts look original and if in good order are worth good money as they dont exist any more.

Paintjob would suggest its been looked after and you have a reasonable chance that with carbs done it will be fine.
HINT:- be very careful with the rubber boots from airbox to carb as they are different from 500 and other 550 and are also not available.

[toomanybikes]

@bryanj - yes, I assume the carbs will be gummed up, but didn't know about the press in jets. I have a '78 Kawi KL250 with similar carbs whose jets were not press in, but still hard to find Keihin parts. The throttle slides might be stuck since the throttle won't move. Haven't yet determined if it's due to gummed up carbs or frozen cable, but carbs are more likely.

Good to know on the carb-box connector availability. At least one of them has already been "fixed" using electrical tape. The rest still seem amazingly flexible, at last from initial inspection.

Bike has been well cared for, with lots of areas being 100% unmolested and unrusted.

[BRG-BIRD]

That’s a very clean good looking 550! Good luck on getting it running. For carbs and stuck Jets I have used Sierra Carbon Free to clean and free up carb parts with great success. A shop that is trusted told me about it and that is all they use.