Topic: CB550 exhaust rust help!

[cb550man]

Hi all!
I am brand new here so go easy on me 
I purchased my new (old) 1974 Cb550F a week or so ago and am loving it.
After the carbs were tweaking a little more from when I got her she goes like no other!
Absolutely incomparable to my little CD250U I have and now as a result neglecting severely oops 





My massive heartache come with the, what I thought were too good to believe perfect condition pipes.
It seems where the baffles are welded to the exhaust there is some pretty heavy rusting through (one is severe on both under and top side, and two are in need of good repair and one is fine).
Despite me believing she sounds fantastic, it does sound a little hollow and tinny when I'm pushing her and I'm thinking its due to these gaping holes?

I was pretty shocked to see how severe one of the holes was, and am crying because I love the shape the rest of the exhaust is in bar these little sections, for its age.

It would be a damn shame to have to chuck a set of new pipes on the bike when I'm wanting to preserve its originality as best as I can.
So, my questions are, would the cost be too great of an expense for the pipes overall (and I say this as a bloke wanting the most cost effective but best way to repair these, not cutting corners but a way in order too preserve them, but also on a budget), secondly in anyones opinion, are the holes affecting the performance of the bike at all?

Shot of the exhaust from a distance (two exhausts closest to the camera are the main damaged one, and one on the other side also)


Underside of two exhausts closest to camera, One of them the severely rusted one


Close up of severely rusted pipe underside


Close up of severely rusted pipes top side


Close up of the underside exhaust rust NEXT to the severely rusted exhaust


Close up underside of the OPPOSITE side rusted pipe


As I said it would be an absolute shame to turf these beauties, I wouldn't let myself!
Thanks all for your views and opinions!
Dave

[faux fiddy]

Welcome to the forum. Don't be intimidated by anything here.

I had a friend weld a bit of  thin stainless over a hole in a pipe, just a patch that is more flat than anything. It is on a scrambler pipe, and so far so good. Stainless welds pretty well to chromed steel.

Obviously the places you have problems you would have to roll a piece to the shape and pretty much cut it all to fit and try to cover all the bad spots with one  cone shaped piece you come up with.  You would have to have something substantial to weld to at every edge of the piece. It would be tricky and labor intensive and might botch the pipe.

It will discolor your chrome, and it would be pretty tricky  shape, but I'm sure someone has done it.  The smaller the hole the easier.



The alternative is find a used one or repop them one pipe at a time as needed.

[cb550man]

Welcome to the forum. Don't be intimidated by anything here.

I had a friend weld a bit of  thin stainless over a hole in a pipe, just a patch that is more flat than anything. It is on a scrambler pipe, and so far so good. Stainless welds pretty well to chromed steel.

Obviously the places you have problems you would have to roll a piece to the shape and pretty much cut it all to fit and try to cover all the bad spots with one  cone shaped piece you come up with.  You would have to have something substantial to weld to at every edge of the piece. It would be tricky and labor intensive and might botch the pipe.

It will discolor your chrome, and it would be pretty tricky  shape, but I'm sure someone has done it.  The smaller the hole the easier.



The alternative is find a used one or repop them one pipe at a time as needed.

Thanks mate appreciate the response!

I've emailed a few exhaust repair specialists here in Oz (all out of my state, dammit!) with details and pictures as above and hope I can get some quotes back in a few days.

I would do the patching myself but A) I would #$%* myself silly and B) I have never touched a welder in my life (MIG, TIG, WIG, FIG?) so it would be a disaster of Hindenburg proportions.

I just really want to preserve these guys because I don't see many with them still on and they sound bloody beautiful AND despite the localised areas, they are in just too damn good shape to turf.
Thanks again!

[youn6372]

The problem your faced with is removing all of the rusted material to get to metal that  you can actually weld on to and work with.  Looks like with this set, that could create more issues = $$.  A friend of mine scored a nice exhaust for less than $500 shipped.  Good luck and nice bike.

[strynboen]

 you  must remove rust before velding repareir pieces inn.

.i can see it vill take a lot ekstra..there are more rust under the thin crome..so the holes vil get 4 times bigger...but it can be done..but it can be seen after the vork..evt paint it vith heat resist silver paint..think there are 4-5 auers veld/grind/paint work

[faux fiddy]

The problem you have is very common to these bikes,

Yeah, common enough that you could market a partial repair  cone to weld it yourself.

If you were to do it, Inert gas, and make sure it's not breezy or a fan blowing,  if your inert gas blows away from the spark it will burn a hole in the thin metal. Found that out welding a fender that is similar steel. Lowest possible settings for most welders.  It would also be good to have something behind the metal when you weld to suck up heat, but it can't be steel and it would be next to impossible to get it out after you welded it.  Maybe a clay slug that you could break up and shake out.

There is a guy that has a laser welder here, and he does good work I hear, but that's all I know about that process. Other than you're looking at $35,000 (liberal estimate) to get set up with that stuff, but who knows, the price might come down as it becomes more available.

[cb550man]

Hi guys and thanks for all your insight!

I just got off the phone to Terry, a bloke that does this stuff professionally in another state (Red-line in S.A), and he pretty much told me after a few feeler emails, that he would touch these with a barge pole.
He said the only thing that could be done, and it would be an unknown time it would work for, would be patching with stainless, as you guys have said.
In patching it though he said they would be fairly messy as they would have to be very large (comparable to the hole size) and the discolouration from the weld would be noticeable. Re-chroming or ceramic coating would also be impossible, as the pipe wouldn't take it, it would be so thing it would just peel away.

So no good news The only things that can be done is a) find a new set of pipes and b) patch it with aluminium can with hose clamps....whilst looking for a new set!

Damn sad to see these be so useless despite my thoughts cosmetically they were great 

SO this leads me to my next question. I know this has been asked a few times here, but none seem to be that current so I will shoot again. IS there ANYONE out there who makes a reproduction cb550 exhaust or even better, anyone who is selling some original/oem ones other than having to trawl eBay for months until I land some semi ok ones?
I have checked DS spares as a post here mentioned he sells them but to no avail.

Thanks guys and I really appreciate your responses!
Dave

[Damage Inc]

cb550man,
If your in Victoria, I might be able to help you with a repair. It just depends what sort of finish your looking for, as to how much. Generally if you want it to look like new again and you can still purchase new sets, that's the cost effective way to go. The rust effected area will be bigger than what you can see. An example of discoloring on a 2 stroke pipe welded with oxy.

[strynboen]

oxygen are the best velding for old rusty thin iron..