Topic: CB550 Four K3 1979

[bryanj]

WD40 or vaseline works well

[Cruiser]

Magnet wont help, alluminium aint magnetic

That's also true. But I thought of another solution. You can easily create a "vacuum" cleaner with the compressor and a piece of hose.

You take a piece of hose, make an incision and blow out air, place the other end inside the cylinder and that piece of pipe will suck.

So I might "vacuum" the cylinder before continuing.

[newday777]

Is there a trick to get those rubber grommets in on the front fender?

I've been strugglin getting these in...

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Edit: well finally managed to get one on... fiddly kind of stuff lol

Vaseline and a small flat screwdriver (very gently!)

[bryanj]

The early ones dont have the grommets just bolts and washers

[Cruiser]

Yesterday I finished rebuilding the carbs (see photo of the progress) they came out pretty nice.

Brakes are next on the list They where all seized up, luckily I was able to free them up.

Any tips on thoroughly cleaning the inside without doing damage? I've seen video's of people putting sand paper in it and it give me shivers to scratch them like that and ruin a decent seal. I've got the complete rebuild kit for both caliper (new piston + seal) and master cylinder. Maybe even the finest steel wool 0000 would be to hard? Also cleaning the ring where the seal won't be easy to get to. Should I put them in the ultrasonic cleaner? Or just manually clean them?

Would appreciate tips 

[bryanj]

Dental pick to clean seal groove, especialy corners. Slight scoring of bore is of no consequence as it dont seal there

[newday777]

The carbs look nice.
A dental pic is the way to clean out the seal groove.
You could put the calipers in the ultrasonic cleaner with heat to clean them out.

[TwoTired]

Right angle scribe to clean the grove.

Abrasives sacrifice some of themselves during the abrading  process.  If you use steel wool on aluminum, steel particles are left behind.  This promotes corrosion when any electrolyte comes in contact with the dissimilar metals. (Like water)

So instead of steel wool use an alternative, like nylon based scotchbrite.  You can obtain it in similar grades to steel wool oooo, ooo, etc. to give the surface finish desired.

[Cruiser]

Got me a set of angled picks to clean out that brake caliper seal groove, so that's going to be great.

Considering steering lock, I'm also left in the dark where the bolt should actually lock into (on the ignition lock). I've looked at the parts list as well but I don't really see the location where this bolt should normally lock into. I assume I'm missing the lip on the frame (see attached), or that something has been altered in the past.

Considering the lock on the stem that seems to be seized a bit. I can turn the key about 20° left, but nothing really happens (also after pushing it in a bit).

Edit: Looking at pictures from other frames, I am missing the lip on the frame. Did these brake off so easily? Or did they remove these for certain reasons?
Edit2: Altough looking at the CB550 Assemble Manual topic here, I don't see the lip either... But that's an older version bike... I'm confused now  Pretty sure you guys will be able to solve my mystery

[newday777]

It sure looks busted off the weld.(your picture enlarged)

[bryanj]

They dont break easily but do get bent when people fall off as they also act as fork stops.

[Cruiser]

Odd that this is gone then, since the bike doesn't really look like its dropped or been in an accident.

What about the lock on the stem? How does this work and why did they even use 2 locks (Steering lock on the ignition and the stem lock)?

[Little_Phil]

European bikes did not have the combined ignition switch/steering lock. So your switch may be a replacement. Maybe the arc of metal on the frame was never there. Bike had a separate steering lock (probably with a different key) accessed from the side on the headstock.

[Cruiser]

European bikes did not have the combined ignition switch/steering lock. So your switch may be a replacement. Maybe the arc of metal on the frame was never there. Bike had a separate steering lock (probably with a different key) accessed from the side on the headstock.

That could make sense then. I do have 3 keys, 1 for the ignition, 1 for the seat and one for the lock on the headstock. But that lock on the headstock doesn't do much. Can only turn it 20°.
I'll have to take a look why its not moving.

[newday777]

European bikes did not have the combined ignition switch/steering lock. So your switch may be a replacement. Maybe the arc of metal on the frame was never there. Bike had a separate steering lock (probably with a different key) accessed from the side on the headstock.

That could make sense then. I do have 3 keys, 1 for the ignition, 1 for the seat and one for the lock on the headstock. But that lock on the headstock doesn't do much. Can only turn it 20°.
I'll have to take a look why its not moving.

Do you have stops on the bottom of the steering neck?

[Cruiser]

European bikes did not have the combined ignition switch/steering lock. So your switch may be a replacement. Maybe the arc of metal on the frame was never there. Bike had a separate steering lock (probably with a different key) accessed from the side on the headstock.

That could make sense then. I do have 3 keys, 1 for the ignition, 1 for the seat and one for the lock on the headstock. But that lock on the headstock doesn't do much. Can only turn it 20°.
I'll have to take a look why its not moving.

Do you have stops on the bottom of the steering neck?

Yes I do.

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[bryanj]

To use the headstock lock you turn the key, push it in and return the key to remove BUT it only works in 1 position IF the steering stem is the correct one with the slot machined into it for the lock

[Cruiser]

To use the headstock lock you turn the key, push it in and return the key to remove BUT it only works in 1 position IF the steering stem is the correct one with the slot machined into it for the lock

Thx, I'll have another look at that. I thought you needed to push it in first, and then turn. Haven't tried it the other way around yet!

Another question concerning brake fluid. I was thought that DOT3 was mineral oil (which is what they had back then) and that DOT4 was synthetic. A long and forever ongoing discussion is mineral vs synthetic... Synthetic would be "bad" for seals from older spec bikes. However, some report no issues, others report leakage.

ANYWAY apart from that discussion (that also has lengthy threads in this forum), what are you using? I'm going to place a steel braided brake line since its still going to be a single disc brake and I do prefer the steel brake lines for this. So actually, what seals are left, just the one in the piston which is also renewed by a new seal (and probably manufactured by modern spec type of seals) so I'm considering DOT4 brake fluid?

The engine itself however I'm more reluctant and probably will put in 10W40 mineral oil.

And last but not least, battery wise, who's is still rocking the classic type of battery with lead-acid? I'm thinking of changing it to AGM type. Mine used to have the Yuasa YB12A-A but I see no reasons for keeping the lead-acid battery.
I've never owned a bike old enough to still have the lead-acid type, so hence my question. All my other bikes where AGM or Gell batteries, and I never really had issues. Gell however requires a higher voltage to charge, so I suspect AGM might be the best bet.

[dave500]

AGM and gell are still lead acid batteries.

[Cruiser]

AGM and gell are still lead acid batteries.

Well AGM and gell are maintenance free... That's what I meant, the original Lead acid's you needed to top off with acid fluid.

[newday777]

Dot4 is fully compatible for our bikes. I've been using it for years without any leaks. Flush it yearly with fresh, new bottle.
I just changed the bars on my K5 750 and went on stainless steel hoses. Much better brake response.
I put in a old school wet cell Yuassa 4 years ago, kept it on a smart tender over the winter's as well as during the week while it was parked. It held up well until this spring so I put in an AGM this time around but I'm still keeping the wet cell for my project bikes in my shop.

[newday777]

Be careful on using 10w40 in summer heat. 20w50 is a better oil in summer conditions.

[Cruiser]

Be careful on using 10w40 in summer heat. 20w50 is a better oil in summer conditions.

Well I'm located in Belgium, so it doesn't usually get that warm here. But I'll check the temp charts for the oil again.

You go mineral then I suppose?

[newday777]

Be careful on using 10w40 in summer heat. 20w50 is a better oil in summer conditions.

Well I'm located in Belgium, so it doesn't usually get that warm here. But I'll check the temp charts for the oil again.

You go mineral then I suppose?

Yes conventional oil for the most part. I've tried synthetic but didn't find any great differences in my bikes using it so I went back to the conventional oils.
Back in the 70s I used Castrol 20w50.
Today I have a few cases of honda 20w50 for the summer heat that came from the estate of a friend who I bought my K5 750 from, and I use a diesel oil in 15w40 for the cooler months of the fall north of Boston.

[TwoTired]

Make certain you use an oil with a JASO MA or MA 1 rating.  This is compatible with wet clutches and has the correct friction modifiers for cam components.

Brake fluid is glycol based, either dot 3 or dot 4 work fine.  You only get the higher temp spec when dot4 is undiluted.

Dot 5.1 is also glycol based and can be used as well.  It’s higher temp spec is valid only if undiluted.

Dot 5 is silicon based.  Don’t mix with any other fluid, and must be used only after complete cleaning of the entire brake hydraulic system.   As silicone can’t be diluted, It must be forever used thereafter, as it can never be completely flushed out.