Topic: Carb reinstall 1976 CB550

[Solid Lifters]

Okay, gotta' blow off a little steam first.  I've been workin' on my cars bikes and boats for nearly 50 years and I've gotta' say that I've never seen a more poorly designed or aggravating to work on arrangement than the carbs and air box on this (new to me) CB550.  I hope the designer gets to spend eternity in a firey shop R & R'n the carbs on one of these. 

That having been said, I just spent a couple of hours trying everything I can think of to get the carbs back in place including the air box.  I've also read everything Google has to offer about R & R'n the carbs, but all of the videos chicken out when it comes to putting it back together.  There is mention on this forum of pulling the manifolds off the back of the cylinders and replacing as an assembly, but given the length of the studs I still don't see how there is enough room that this will help.  Of course the air box has to be sloppily in place before sliding the carbs in and everything rubber then creates an interference fit of almost an inch.

With a helper we forced the carbs out one side about a month ago, bending all of the band clamps to the air box and knocking several of the rubber boots out of the box also and even then it took enough force that I fully expected to break something.  All suggestions appreciated including something to calm nerves.

[goodtryer]

Yes, it's a frustrating job.

Personally, I completely remove the band clamps, loosen the airbox like you said, remove the nuts from the intake runners. Then I push the airbox rubbers partially into the airbox; you have to fold and push and deform them but you can get them basically out of the way. Then you'll have enough room to pull the carb assembly rearward enough to clear the head studs. You'll tilt the carbs down at the rear and they will start to twist out of the intake rubbers. At that point, they are essentially free. Check the manual. I believe it says which side to slide the assembly out of the frame. It's easier one way than the other.

You can do it! Don't forget this is supposed to be a fun hobby. If you're getting frustrated, take a break.

PS. There are those (myself included) who have replaced the studs with bolts which makes this process much easier BUT you take on the added risk of messing up the threads in the head/jug. CAVEAT EMPTOR.

[ekpent]

Yes the design sucks. I have also said it here before. 750's are super easy. Some other brands of vintage bikes I own are not as tough as the good ole' 500 and 550's. I dread working on them. Good luck and have fun !!

[craz1]

Also helps to have new pliable air box rubbers.

[jonda500]

Yep, loosening the airbox by removing all the retaining bolts gives a few mm's of extra clearance.
Completely removing the air chamber side band clamps out of the way will stop them getting all bent up when sliding the carbs in or out.
Personally, I leave the inlet manifolds on the head and don't undo the front band clamps, & I leave the air chamber rubbers alone, but use care when dragging the carby mouths past them.
Warming and lubing the inlet rubbers will make the carbs slide into them easier!
Good luck, John

[gmoss]

buddy, you and me both: http://forums.sohc4.net/index.php/topic,186913.msg2166914.html#msg2166914

sticking your hand into the cleaner and pulling the rubbers back into the box is the only way i've been able to do it.

 

There is mention on this forum of pulling the manifolds off the back of the cylinders and replacing as an assembly, but given the length of the studs I still don't see how there is enough room that this will help.

when guys talk about doing this, they've replaced the studs with bolts -- notice at 1:36 in this video:

[Deltarider]

A few comments on that video. I have my own method for removal, but if I had removed the intake manifolds, if, I would certainly inspect the four 30,8 mm O-rings. In stead of the 16 crossheads that hold the floatbowls, I have allen bolts since long. They will facilitate roadside inspection and an allen key easily fits in the toolbag.
I don't get why Mike Nixon recommends a sync here.  Work done in float chambers will not affect sync.

[Solid Lifters]

So I FINALLY got the carbs back on today.  I took Goodtryer's advice and replaced the studs with bolts.  I honestly don't think I have what it takes to get the carbs back on otherwise.  Thanks for all the help.  The gas tank and petcock are going to get some attention before going back on so I plan on wetting all 4 carbs tomorrow and givin' starting it a try for the first time in about 18 years.

[Kevnz]

I sure hope the carbs don't leak out the overflows. That can be a real pain to cure and often requires the carbs off several times to get right. I've had them off so often, I can have the carbs on the bench in 15 minutes from starting. As mentioned, pushing airbox rubbers into airbox gives "just" enough clearance. Remove to right side. I agree with the idea of replacing the bowl screws with cap screws, but if you get your needle valves sorted properly, hopefully that will be the end of it and you won't need to delve in there for a long while. I've found polishing the needles and seats with metal polish until the needles pop out easily cures leaking problems. Once you've got it sorted, these hassles will just be distant memories and you can get on with enjoying the ride.

[Deltarider]

... Remove to right side. ...

To right side is for CB500, to left side is for CB550. Has to do with the clutch cable in the way.

[Kevnz]

... Remove to right side. ...

To right side is for CB500, to left side is for CB550. Has to do with the clutch cable in the way.

True, but I think the 550 cable is pretty easy to remove compared to 500.

[Bankerdanny]

Definitely a pain. The only good thing about the pods my 550F had on it when I bought it was that it made removing the carbs a snap, which came in handy when I was camping outside Monument Valley in 2017 and had to pull them to deal with a sticking float.

Pliable boots on the airbox are important and heat is your friend on the intake side. Break out a hair drier or heat gun and warm up the intake boots as much as you can without melting them. Then a little lithium grease or petroleum jelly to help things slide together. For the airbox side a heavy duty pick with a 90 degree bend helps get the boots onto the carbs.

[TwoTired]

When all the rubber bits are pliable it isn’t so bad with the clamps on the air plenum couplers completely removed.  Easier with the filter box loose.  I’ve never removed the manifolds.

Next time I do it, I think I’ll smear some wintergreen oil on the rubber bits a day or two ahead of time to soften and slightly expand the rubber.

Cheers,