Topic: Intake compatability on my 550K

[JG550]

So the first thing to come up on my bike so far, is that the rubber intake boots running between the air chamber and the carbs have dry-rotted just enough to shrink back and let a bunch of air in. I've read in a few old posts that the carbs and intakes were different on the '78 than previous years (and i've noticed the completely dif part #s), so while an entire chamber from some other year wouldn't work, would just the rubber boots work at all or are none the same dimension? I ask specifically because there's a set off a '75 550F on ebay right now, and my next alternative seems to be ServiceHonda which lists the entire chamber for about $70 (my local Honda guy's searching had turned up empty).

[bryanj]

Unfortnately the early rubbers wont fit, and having dealt with Service Honda i will bet that if you order it they will tell you "No Longer Available." These and the exhausts are the majour discontinued items from the 77/78

[puppytrax]

Unfortnately the early rubbers wont fit, and having dealt with Service Honda i will bet that if you order it they will tell you "No Longer Available." These and the exhausts are the majour discontinued items from the 77/78

Bryan - Although it is rather a radical "fix", would it be practical to replace those "new style" carbs/airbox/booties with the complete induction setup from a 75/76??? I'm not contemplating it, and don't have any desire to experiment, but just from looking at the Fiche (and eBay), it seems like the manifolds to the airbox would all fit...

[TwoTired]

The problem stems from the fact that the 77 and 78 K carbs are a different casting than all the previous models.  The intake mouth is a different diameter as well as the length of the carb and intake runner assembly.

I might be possible to adapt the mix of components. But, it won't be a drop in arangement.

Cheers,

[clarkjh]

Check here

http://www.cmsnl.com/partslist.php?model_id=465


Look under fuel tank air cleaner - Part #19
It says they have stock, 93 Eruos for the whole thing

James

[JG550]

Unfortnately the early rubbers wont fit, and having dealt with Service Honda i will bet that if you order it they will tell you "No Longer Available." These and the exhausts are the majour discontinued items from the 77/78

Thanks Bryan, thats pretty much what I figured the case would be. Thank goodness my exhaust is pretty damn mint at least!

The problem stems from the fact that the 77 and 78 K carbs are a different casting than all the previous models.  The intake mouth is a different diameter as well as the length of the carb and intake runner assembly.

I might be possible to adapt the mix of components. But, it won't be a drop in arangement

Thanks TT, that's exactly what I wasn't sure about. I figured I could probably get away with a different setup so long as it was tuned properly, but would I want to? Not really...

Check here

http://www.cmsnl.com/partslist.php?model_id=465


Look under fuel tank air cleaner - Part #19
It says they have stock, 93 Eruos for the whole thing

James

Thanks James, but my model is actually this one: http://www.cmsnl.com/cb550k-78-us_model7222/partslist/F++16.html
and if you scroll down to part #12 you see the lovely "Not Available". Thanks for the link though, as I have one more bookmarked page to dig through for parts.

[puppytrax]

I might be possible to adapt the mix of components. But, it won't be a drop in arangement.

What about the complete assembly??? Airbox+booties; carbs; insulators; and aluminum manifolds from a 75/76??? That would be an 087A or 022A carb setup, rather than the later castings.

[TwoTired]

What about the complete assembly??? Airbox+booties; carbs; insulators; and aluminum manifolds from a 75/76??? That would be an 087A or 022A carb setup, rather than the later castings.

I should think that would work.  However, I confess I have NOT tried that.  And you would lose the bar mounted choke knob.

Another member had difficulty with the air plenum coupler availability.  And, fortunately found a useable one on Ebay.    I have a couple spares that I that I think are useable, though they look to be a bit deformed from having been installed in the plenum incorrectly for some long period of time.

I was wondering if I could use an old one to make a mould from and then cast new ones from RTV or a casting rubber dyed black.

They would be kind of expensive if done that way.  But, if parts become unobtainium.  A resto business could be spawned.

What are they worth?

[puppytrax]

Another member had difficulty with the air plenum coupler availability...A resto business could be spawned.

Is that the big oval rubber gasket that fits inside the hole??? You might want to check electrical suppliers; I don't recall what they are called...bulkhead insulators or somesuch; they're even used on autos. For when wires go through holes in sheet metal. I know you can buy the little ones at places like RatShack; the bigger ones are harder to find; used in industry mostly.

[JG550]

Another member had difficulty with the air plenum coupler availability.  And, fortunately found a useable one on Ebay.    I have a couple spares that I that I think are useable, though they look to be a bit deformed from having been installed in the plenum incorrectly for some long period of time.

Yeah I've been watching ebay for them the last few days, but have only found a couple for earlier models. The ones I have on right now, they're not rock hard, but it seems mostly that they've shrank to the point that they're just not long enough anymore. The way the weather's been lately I could probably sit those deformed one on the doorstep for five minutes before installing them and be fine.

What are they worth?

Seeing as it's the only thing at the moment (knock on wood) that's keeping me giving it a tune up, probably whatever price you name. I don't want to make an ass of myself and throw a price out there, but if you think they've got some life left in them and are willing to sell, please shoot me a PM or an email.

Thanks, Geoff

[JG550]

Another member had difficulty with the air plenum coupler availability...A resto business could be spawned.

Is that the big oval rubber gasket that fits inside the hole??? You might want to check electrical suppliers; I don't recall what they are called...bulkhead insulators or somesuch; they're even used on autos. For when wires go through holes in sheet metal. I know you can buy the little ones at places like RatShack; the bigger ones are harder to find; used in industry mostly.

Yeah this is what they look like installed (or at least on my outer cylinder), running between the chamber and the carbs:



but if you look at the pic in this auction for a set off a '75, they're not exactly straight pieces of tubing: http://cgi.ebay.com/ebaymotors/Honda-CB550-F-Original-Intake-Boots-1975-Nice_W0QQitemZ190012427113QQihZ009QQcategoryZ35597QQrdZ1QQcmdZViewItem

[TwoTired]

Is that the big oval rubber gasket that fits inside the hole???

I don't think so.  That oval one sounds like the one that joins the air filter box to the air plenum. 
The parts JG550 is looking for go between air plenum and carbs and there are four of them.  They look like velocity stacks when they stand alone.  There are two molded types for the inner and outer positions.  I only have three spares for the 77-78, two inners and one outer (deformed).

That ebay seller clearly doesn't know the 75 couplers are different moldings than what is found on the 77-78 models.  Or, he doesn't care.

If your's are simply too short, could they already be from the wrong bike?

Cheers,

[bryanj]

If things get desperate here is an idea, Get some thin walled rubber hose that just fits over the carb and cut some lengths to run just inside the airbax then seal to the box with black RTV. wont look original but should work.