Don’t make the mistake I did (driven by enthusiasm and ignorance) in buying a set of CB750 header pipes and thinking they would fit your CB550 engine. They won’t. Header pipes for the CB750 are much wider in diameter (and probably different in shape and length). The CB550 header pipes are 1 and 1/4” O.D. They also run so close to the oil filter hosing that anything wider or imperfectly shaped will bump right into it. As I found out so many times during this project, HONDA engineers and designers knew exactly what they were doing! Thinking that I could do better or different was a constant embarrassment and frustration.
A set of original headers and mufflers in perfect condition is not easy to find and when one comes up occasionally on eBay, prices go through the roof. I would prefer to leave those who are restoring their CB550’s to bid on original components as they do not really have much of a choice.
Custom bike builders have a greater flexibility with at least these two options in mind:
OPTION 1: Find a good set of original header pipes, have them re-chromed if necessary, install a new set of aftermarket mufflers, and mount them on the machine without any frame modifications.
OPTION 2: Custom made stainless steel header pipes and aftermarket mufflers of choice.
In pursuing OPTION 1, I bought a set of original HONDA headers (my CB550 was the F version having 4 into 1 exhaust and since I wanted 4 into 4 I could not use the ones the bike came with). When connecting them to the mufflers I noticed that the 1 and 1/4” O.D. original headers required a number of shims (adapters) to connect to the 1 and 3/4” I.D. mufflers. The assembly looked really ugly with a sharp transition between pipes and mufflers. I also noticed that the 40 year old chrome on the original header pipes (as good as it was with no flaking or rust) did not match the new mufflers’ chrome. In order to make a good looking seamless transition from headers to mufflers, modifications of the headers was needed and then they would have to be re-chromed. Inquiring about the cost of doing that, I found out that re-chroming all 4 headers would cost anything between $600 (for a basic job) to over $1,000 (for a show quality job).
Pondering the complications and price, I decided to investigate OPTION #2. (This decision was made easier by the fact that original header pipe #4 is indented by design. The indentation faces outward and is positioned immediately under the U-bend of the brake pedal so I assume the header pipe’s indentation is needed for clearance purposes. I didn’t like the look of the indentation in the pipe and, more importantly, did not need it. The CB550F, because of the fact that the brake pedal must clear all four pipes, has a brake pedal that is extended outwards. At that point, I did not know that I would end up choosing to go with a custom aluminum brake pedal.)
Pursuing OPTION #2 was easier said than done. There are many custom motorcycle outfits that can do the job, but all of the ones I contacted wanted to have the bike in their shop (understandably enough) so they could fit the header pipes to it perfectly. The price? $1,500 and up.
I then called a number of professional outfits that bend pipes for a living and asked them if they could make exact replicas of the 4 original HONDA headers. None of them seemed to think this would be a problem. The price? Don’t know. Maybe $500, maybe $600 depending on the number of different radiuses, they said. Deal. (This did not include welding on the collar that is needed to press the pipe into the engine’s exhaust opening and which also compresses the copper seal) or welding on additional cones and piping to allow for a seamless fit between the pipes and mufflers). The first “pipe bender” I took the original pipes to sat on them for more than a month and did nothing. The second one decided after more than a month that this wasn’t something they really wanted to do. Dead end.
Enter my friend and welding wizard Ulf Pichl of Swedish Stainless who lives in a picturesque village North of Stockholm, Sweden. I called Uffe and asked if he could do the header pipes. It just so happened, he said, that he had a CB550 somewhere in storage and, yes, it should be no problem. And so, I found myself in Sweden in Uffe’s workshop in which he made the header pipes in a day. He had brought his CB550 there and so making the pipes and fitting them was not an issue. He also welded the cones that were needed to transition from 1 and 1/4” O.D to 1 and 3/4” O.D. (The additional 2” long straight sections were welded later when I came back as we could not do this in Sweden without the mufflers. See the note on precision below.)
The picture above shows the finished header pipes #3 and #4. Note the cones and the “transition” terminals.
A few words about precision. The angle and length of the end terminals of the header pipes where they transition form 1 and 1/4” to 1 and 3/4” must be absolutely precise in order to allow the mufflers’ ends to sit exactly above one another in perfect vertical alignment and to be at the same distance from the ground, the same distance from one another and the same distance from the wheel or rear shocks and without contact as they cross over one another.QUESTIONS?