My headers are in great condition, my crossover looks to be in good enough condition that I could scrub and spray with a high temp silver. Just the mufflers need replacing. Anyone on this forum do this before. I’d love to just copy someone…I don’t have much time so I like to be as efficient as I can. Lol
I'm thinking of maybe buying a pair of mufflers and bringing it to a muffler shop and have them install it. I assume most mom and pop car muffler shops would do this? How much do you think it would cost for installation, and possibly have them redo the crossover if necessary?
Yes, they can easily do it.
Around these parts they just refuse the work on bike exhausts though, because they have such high value orders coming in all the time (the "tuner" car scene, with custom exhaust systems and valves and stuff).
I've got a little experience dealing with rotted exhausts - we get salted roads here and if you're into old bikes, the exhaust often has problems. So I've got a few tricks.
You have a few options:
1) Get good quality mufflers which will fit the diameter of your pipes (get quiet/legal/semi-legal ones because these bikes make a racket when you get the revs up), and clamp them on to your downpipes using heavy duty exhaust clamps. You can get these anywhere, but the tricky part is you may have to cut slots in your muffler so that the clamps have something to bite, and you'll have to be careful with your measurement and how much you cut.
2) Get good quality mufflers as above, and get a shop to weld them on for you.
3) Get good quality mufflers, and weld them on yourself. I've done this myself, with a stick welder, on my Yamaha's exhaust, and while the results weren't beautiful it was effective. You just need to sleeve, double-sleeve if necessary, and drill holes in the downpipes and exhaust to expose the sleeve underneath, put a dab of weld in them while not blowing them out, and when done you can butt-weld at the join of the mufflers and exhaust, and grind down.
I'm a trained/educated civil engineer and it seems to me that stick welding isn't the most ideal method of welding an exhaust since its generally used for structural means (in my field and knowledge area anyways - I'm not a mech engineer). I know how to calculate E70 electrode (and similar) weld strengths for structural elements, but that's were my knowledge of welding begins and ends. Perhaps this is a good time for me to purchase a welder and do the job myself? All these mufflers are stainless though. Are the stock pipes stainless? I'm sure that makes a difference when deciding upon what type of welder to purchase.
Oh no. I may be an engineer but we (civil) are not taught the differences between welders. As a civil engineer we only deal with electrode style (E70) stick welding because its the only type that can be used for large scale structural purposes. If I were a trained mechanical engineer I'm sure I'd know all about welders. But I don't. I'm dumb as a box of rocks when it comes to welders. Please do inform me if you're able. I've always wanted to learn to weld, so maybe this need to replace my mufflers is the type to buy a welder and learn, and fix my exhaust. I'm willing and able.
I'm guessing a flux core is probably the way for me to go though
I think that it should be a fairly straightforward process to cut off the rotten mufflers (since you're thinking of replacing entirely). I might use a large pipe cutter, if it can handle the steel, just to ensure a nice edge.
At that point, if the diameter of your new muffler's inlet matches the header pipes of your stock exhaust, slip the muffler on and see where the hanger is. You may need to cut more off of your headers or make a bracket for each muffler - not difficult. It might be good to keep the headers mounted or put them back on after cutting the mufflers off if you can, to make the mockup process easier.
Once it looks right, you can honestly probably get away with some exhaust assembly paste and a tight clamp - but as another suggested, you can cut slots in the new muffler's inlet point so that the metal can "grab" more effectively:
As mufflers on some shaft drives have, and if memory serves, the headers on inline-4 KZs have connections like this for two of their header pipes.
It would be ideal to find a muffler that matches your header diameter as closely as possible, but if there's some gap then there are ways to fill or gasket that.
Sorry for the long post...been through a lot lately.
Ohhhh there's plenty of people who hate on engineers because they are educated and think a certain way. That's why I quit practicing, I no longer consider myself an engineer despite my education and extensive background. I quit because the day to day grind trying to work with people who have a predisposition of engineers. It wasn't so bad working with people up until about 10 years ago...there was a huge and sudden shift of people to hate those they don't know just because they are educated. I've been very much straight forward here on this forum. I have no problem at all letting people know where I am blatantly ignorant. But when it came to doing my work in the field, where I'm very much more qualified to make decisions was always a fought with a bit of snarkiness, and backhandedness. Sorry to have triggered you somehow.
@Steve - the method of repair will depend in very large part on what you want the final finish to be.
If you're going to use paint or a ceramic coating, you can get away with a little more as far as welding, grinding, and fixing imperfections. If you want to have a full chrome system, you should be prepared to have a shop do the assembly, media blasting, and replating. Chrome is not very forgiving and the underlying surface must be in good shape for the finished product to look good.
And contrary to what you were told upthread, the stock exhausts are NOT stainless. If they were, we wouldn't be having this conversation.
The factory exhaust is chrome over (IIRC) mild steel.
Fortunately the stock headers (just ahead of the crossover) have an OD of 1.5", which will probably make your life a little easier re: finding mufflers and other parts.
1979 KZ400 Gifted to a couple of nephews
1967 Yamaha YCS1 Bonanza
1981 Yamaha XT250H
1981 KZ440 LTD project bike
2013 Yamaha FZ6R
82' KZ750-R1 cafe racer style. Clip-on, Rear set, Fork-Brace, Mikuni Flat-slide (forgot the size), Kerker.
84' GPz750 (basket case). everything are in pieces.
89' ZX750-H1 (ZX-7 Ninja). Resurrection project are on going with my KZ750. Everything is stock.
Here's a KZ650 w aftermarket mufflers clamped on to the stock pipes.
With aftermarket you may have to use reducers to make up the difference in diameter.
The 440 mufflers are probably shorter, especially if it's an Ltd.