Topic: More carb challenges...'78 CB550K

[jbswearingen]

Okay, so the 1/16" cork/rubber gaskets that I cut out seem to be holding the carbs sealed against leaking.  Time will tell.

Yay!

I can't get the dadgum airbox to line up with the carbs, so I'm seriously considering air pods.  Anybody have a good recommendation for 38mm pods?

Now then, after I removed the airbox and put the carb bank back on (I'm getting pretty good at it now), I filled the bowls and then removed the gas tank.

I can just get it to start and run at high speeds (not below 3k rpm).  When I pull the choke button, the fargin' butterfly valves don't close!  If I push them with my finger, they'll pop into place, but when I start the bike, they want to open back up again.

The choke cable is pulling the lever, and is releasing the valves, but for some reason they're sticking.

I also notice that the 3rd and 4th carbs' valves operate independently from 1 and 2.  1 and 2 stay closed rather well, but 3 and 4 flutter greatly.

So, back to this sticking...Where should I lubricate and with what lube?

I'm sure I'll have more q's later on...

[Tvag]

Regarding the butterfly valves, it's possible that they were not lined up correctly on the bar. Did you take the valves off the bar that swivel on at any point? I have not been following your progress. If so then when you screw the valves back on you must do it when they are in the closed position so you know that they are lined up correctly. I had similar trouble. You may have to pull the carbs again. 

Tvag

[jbswearingen]

I've pulled the carbs again.  I'm getting REALLY good at it.

Pulled the airbox, too, and tossed it for useless.  It hardly lined up properly any way.  Gonna put pod filters on it.  I measured the intake throats on the carbs, and I read 38mm, but all the pods I see are for 39mm.  I'm sure they'll work, as the rubber will be compressed when clamped down, but before I order them, should I try to find 38mm instead?

I pulled the bowls and all eight jets.  Pulled the floats and valves.  Pulled the air screws.  Pulled the tops off the carbs and dropped the whole bank (and jets/floats/etc.) into an ultrasonic cleaner with a very high concentration of Simple Green in water.

They've been going for an hour now, and I'll probably leave them over night.  There was quite a bit of crud inside the carb bodies.

I've seen many here mention that the non-adjustable carb is the second one, so that you set all the slides to that one.

Well, on this bank, it's the first carb that is non-adjustable.  I haven't looked closely, but I don't yet know if the carb bodies can be switched around.

Do I have a switched-around bank of carbs or is this correct?  Could this be the root of my evils?

[neil young]

read this...you will find it quite helpful

http://forums.sohc4.net/index.php?topic=29437.0

[jbswearingen]

Thanks!

[jbswearingen]

Anybody have any input on the 'adjustable' carb in my set up?

[spate51]

I found that if the choke doesn't work easily, if you carefully loosen the screws on the choke butterflies in each cylinder (about 1/2 turn) and work the choke lever, the valves center themselves in the throttle bores.  Then tighten the screws on the choke.  Had to do this when I replaced the O rings on the 3 fuel fill tubes between the carbs.  Be careful you do not strip the screw heads!

[TwoTired]

Anybody have any input on the 'adjustable' carb in my set up?

I guess I have "belief" issue. Post a pic.

The adjust mechanism isn't bonded to the carb body.  I suppose it is possible to swap the adjuster/non adjuster arm between carbs.  But, if you are saying it came from the factory that way...

[mystic_1]

Pulled the airbox, too, and tossed it for useless.  It hardly lined up properly any way.  Gonna put pod filters on it.

I would actually strongly recommend getting it running properly with the stock configuration before making a change like that, otherwise you're compounding issues one on top of another, and diagnosis becomes exponentially harder.

Get it singing with the stock airbox, then change to pods and re-adjust as necessary.

mystic_1

[bozo4onion]

Changing to pods is not just a filter choice. You'll need to, at the very least, change one or more jets. Then the needle clips and on and on. I just spent $$$$ converting mine back to stock. It runs much better. may sacrifice top end HP but low end seems better. Genarally runs smoother. With stock you'll always know your proper jet values and needle clip setting. Even worse if your bikes not running now. Your problem is not the airbox. Why trash it. Good luck. If you do switch post the box on eBay. Do you wonder why they sell? People want their bikes running right again.

[jbswearingen]

I guess I have "belief" issue. Post a pic.

The adjust mechanism isn't bonded to the carb body.  I suppose it is possible to swap the adjuster/non adjuster arm between carbs.  But, if you are saying it came from the factory that way...

And you know, I just got done putting the damn things back on!

I have no clue if it came from the factory this way.  I think I'm the third (or more) in the ownership line.  I've gotta pull them apart again, anyway.  Stripped one of the float bowl screw threads and will have to retap for a larger screw.  Any advice on that, friends?

I would actually strongly recommend getting it running properly with the stock configuration before making a change like that, otherwise you're compounding issues one on top of another, and diagnosis becomes exponentially harder.

Get it singing with the stock airbox, then change to pods and re-adjust as necessary.

mystic_1

I'm not worried about that being a problem.  I'm gonna put larger jets in it, anyway.  The airbox doesn't line up very well.  Dunno if it's damaged, or what, but it's just a huge pain in the arse.  It's also SO much easier to remove the carbs and put them back in when the airbox isn't there.

I found that if the choke doesn't work easily, if you carefully loosen the screws on the choke butterflies in each cylinder (about 1/2 turn) and work the choke lever, the valves center themselves in the throttle bores.  Then tighten the screws on the choke.  Had to do this when I replaced the O rings on the 3 fuel fill tubes between the carbs.  Be careful you do not strip the screw heads!

I figured out what was wrong--the carb bank was tweaked a bit--they didn't line up properly, so the choke rod (or whatever it's called) was binding.  Loosened the main yoke that holds them all together, realigned, tightened up, and BAM, they work.  Go figure.