Topic: How to fix this header?

[btripp]

Hi guys,

  I still haven't finished my carbs (too much to do at work!) but while I'm working on them I decided it would be a good idea to solicit advice on the next thing to fix: this rusted out exhaust header.


  Can I replace just one of these things or do I have to do the whole set?  I've got the 4-1 exhaust and the other half of this pipe is still attached to the 4 into 1 collector.  It's probably got about 3 or 4 inches missing.  Incidentally, I have the missing part, at least the pieces it crumbled into in my hand!  The other three don't seem to be rusted at all.  Weird huh?

  So...options?

  Thanks!  -Ben

[MRieck]

For the time and efffort involved I'd check ebay etc for a replacement. Is that a 400F?

[btripp]

'77 550F.  You mean the whole set?

[MRieck]

If it's one of the detachable pipes you could try just finding the single pipe. Honda may have the pipe if it is one of the detachables. You would probably have more luck on ebay etc trying for the complete header section. Maybe someone on the board has one....run it in the wanted section.

[cb(r)]

you can replace just one but I think the time and effort might is not worth it.  although, if you have enough good pipe sticking out of the collector you can cut bend and weld on a new piece of pipe.  this is all depending on the tools you have. 
The best idea though, was already stated earlier.  look for a complete good used set. 

[ProTeal55]

I guess it comes down to what you want the fnished look to be.

My buddy just picked up a 73 CB750 , and one of the header pipes was rusted to the point I could
push my finger thru it. We just welded a patch over the hole , and then wrapped all the int. pipes with
black header wrap.
Simple fix , and cheap...

If you don't wanna go that route , I would look over the great and mighty Ebay...

[TwoTired]

Okay, IF your CB550F has the original type 4 into 1 chromed header, it was considered one part and individual down tubes were not available separately. All down tubes were welded together during manufacture, before the chroming operation.

Can it be repaired?  Yes, but not by conventional part replacement means.  I expect a compentent muffler shop capable of building headers from scratch, can fabricate and replace the single tube.  Then you can find a chrome shop and contract with them to have the header rechromed.

I have never seen the original header rust through.  Muffler yes, header, no.  I also have some rusty headers laying around.  But, none rusted through and destroyed as your picture indicates.

Do you think your header is original Honda type?  When you look at the break can you see evidence that the tube was double walled?  I.E a pipe within a pipe?  This would be much more difficult and costly to repair, as I'm not even sure of the process with which they are created.

Let us know...

[Killer Canary]

Any bending shop I've approached about bending pipes for the Canary told me the same thing: they don't have dies that small since the diameter is smaller than automotive.I'm here in the gap, though.
Ended up buying a header at a wrecker for $150.

[btripp]

OK.  I went out tonight and took another look at the busted header.  I don't think it's double walled, but I took another picture so you guys could see it. 

I'm starting to think the pipes might not be original.  It has a Kerker muffler on it and I think the PO may have replaced the whole thing.
The guy told me he had put that on and had modified it with part of a radiator - the hot water filled type you have in your house - to get a different sound.

  -Ben

[cbjunkie]

criminy - your carb threw up in your header!

have you cracked the head open yet? might want to wear goggles when you do...

[Faust]

Don't mean to hijack this thread, but I have a similar problem. Good mufflers on my 550K and blue or rusty header pipes. Does anyone make a chrome clamp/connector so that I could just cut and splice junkyard header pipes?

[cb(r)]

criminy - your carb threw up in your header!

have you cracked the head open yet? might want to wear goggles when you do...

funny stuff lol.   seriously I have as set of what I believe is after market 4-2  that were rusted thru.  just not nearly as bad.  so it is a good assumption that these are not stock.  I am not saying it is impossible to make a piece to fit but there might not be enough good metal inside to weld to.  if it were me I would start looking for a new/ used set.

[Lumbee]

...btripp, I'd weld it up for you if you ship it to me...AND its doable.  You say there is a 3/4 inch section thats missing/rotted out.  If you wanted to give it a try I'm up for it.  New welder, and am anxious for some repair work.    If you could find a replacment section I think it would be weldable...

[Killer Canary]

Lumbee, what have you done with The Great"Radigga"?

[Lumbee]

...well, I'm Lumbee over on hondachopper.com, so try'n to get a little continuity go'n...

[btripp]

Lumbee,

  I appreciate the offer, but I think it may be a little too far gone!  I meant to say that it was missing a three to four inch section of the pipe.  What's left seems to be in not great shape either, so I think I'll just get rid of the whole thing and get a new set.

  Thanks!  -Ben

[Terry in Australia]

Lumbee,

  I appreciate the offer, but I think it may be a little too far gone!  I meant to say that it was missing a three to four inch section of the pipe.  What's left seems to be in not great shape either, so I think I'll just get rid of the whole thing and get a new set.

  Thanks!  -Ben

That's it Ben, I'm a half decent welder with arc, mig and oxy-acetylene equipment, and I can tell you now, that the rest of your header will be paper thin , and you'll only do more damage trying to weld it. Throw it in the trash or save it for spares, but forget fixing it, it's an "EX"-Haust, ha ha! Cheers, Terry.

[Quail "Owner of the comfortable k8"]

Terry are the header pipes off pre-K7 different that the 77-78?  I know the mufflers are different but are the headers?

[Terry in Australia]

Terry are the header pipes off pre-K7 different that the 77-78?  I know the mufflers are different but are the headers?

Yes T2, the K0 to K6 had different mounting arrangements to the F/F1, K7/8 and F2/3. The header shape is similar though, but the bottom line is that they won't fit unless you either mod the headers, or your head. (which is do-able...) Cheers, Terry.

[btripp]

Ex-Haust!  Ha Ha!   

A lot of stuff on this bike is Ex-whatever.  I think I have Ex-Carbs too.  Did you see that post?!

  -Ben

[Terry in Australia]

Ex-Haust!  Ha Ha!   

A lot of stuff on this bike is Ex-whatever.  I think I have Ex-Carbs too.  Did you see that post?!

  -Ben

Not yet Ben, I'll check it out! cheers, Terry.

[btripp]

After looking at my clymer's I'm pretty sure the pipes aren't stock.  They have a square (two over two) collector before the muffler instead of the in-line four collector in the manual.  Can anyone verify that?  The muffler not stock too (Kerker with removable baffels, or so I'm told) and I think the PO replaced the whole thing at the same time.

It does look like they rusted from the inside, as I've heard can happen with these bikes.

-Ben

[Terry in Australia]

That's it Ben, they're aftermarket pipes for sure. Honda had the ugliest collector, although it probably had better ground clearance, and I've never seen an OEM 4 into 1 rot out like yours did? Cheers, Terry.

[btripp]

  Can this thing be converted from a 4-1 into a 2-2 or something else?

  -Ben

[TwoTired]

  Can this thing be converted from a 4-1 into a 2-2 or something else?

  -Ben

What?  You gonna disable two cylinders or hack the motor in half?   The standard options are:
4 into 4  Stock for a K model
4 into 1  Stock for an F model and aftermarket MFGRs
4 into 2  aftermarket MFGRs  But, usually use the stock head pipes.
Best to pick one of these, I think.

[btripp]

Ha ha!  Sorry that's what I meant!   

  But any of those combinations will bolt right up?  What about connecting to the frame near the muffler? 

[Egil]

Ben :
Have a link that my can  help  .
http://www.macperformance.com/store/category.cfm?SID=3&Category_ID=889&CatLevel=3
 
Egil.

[TwoTired]

They all interface with the engine ports in the same way.
There are variations in how/where they attach to the frame, and interference with center stand kick start lever, brake lever, and foot peg.

If you want all new, probably the cheapest is the MAC system 4 into 1.

Best fit would be stock 4 into 4 if you can find all the brackets and fittings to do so.  Probably most expensive, too.

Then there is new old stock, if you can find them.  And, of course the used and salvage marketplaces.  Prices vary.

Depends on what your goals are...

Cheers,

[btripp]

  Thanks for the link and the advice!

  I assume changing the exhaust will require retuning the carbs to correct for different pressures?

  -Ben

[Joe Danger]

Ben,

Loudfastugly.com has original MCSC 4-into-1 exhausts for $219, gorgeous chrome.  (I got one for Christmas.)

Incidentally, I got that umbilical for the fairing.  Thanks so much, man.

-Joe

[TwoTired]

  I assume changing the exhaust will require retuning the carbs to correct for different pressures?

Depends on how well you insist the bike run and how different the back pressure curve profile is from what the carbs are presently tuned to.

[Terry in Australia]

The SOHC 750's are pretty flexible compared to other bikes, particularly those with CV carbs. I'm running my K3 with stock airbox and 4 into 4 pipes with the original (for Oz)105 main jets, and my K1 with straight out drag pipes and pod filters, with 110 mains, which are probably a little lean you'd think, but it runs well, starts easy and accellerates away from the lights fine. (But makes one hell of a racket!)

On the other hand, my Suzuki GS1000S with CV carbs won't run properly with just an aftermarket 4 into 1 pipe and a foam filter! Best rule of thumb is the "seat of the pants" method, rather than going into all the "what ifs", just take it for a ride, and do a plug chop. (Buffo's favourite diagnostic tool) Remember, if it feels right, it probably is! Cheers, Terry.