KZ400 Exhaust Swap

Finally managed to find a used original exhaust for my bike to replace the super loud franken exhaust that it came to me with, after having zero success quieting it down with different replacement baffles.

Question now is what all I might need to swap in the new pipes. Do I need to replace any gaskets? Any tips on getting the old pipes off the studs without breaking anything? And are the pipes I got the style that caused oil leaks due to the crossover pipe? If so should I cap those off? 

Looking to swap everything all at once so if I need more than the missing clamp for the crossover pipe I want to order it ahead of time.

Thanks as always
 

You should replace the gaskets between the pipe and cylinder head, you can use a small amount of exhaust sealer on the balance pipe. With the studs you should soak them with penetrating fluid and repeat over a couple of days (not when hot as penetrating fluid is flammable) when removing the nuts - if they go tight wind them back on and clean the stud with a wire brush, apply penetrating fluid and wind off again (keep repeating this process until the nuts are off)

Thanks, I'll see about finding gaskets along with the metal clamp, but there's nothing I needed to worry about in keeping that crossover pipe?

ThatYeti wrote:

Thanks, I'll see about finding gaskets along with the metal clamp, but there's nothing I needed to worry about in keeping that crossover pipe?

Not that I am aware of

Any idea which gaskets are a better option? Seeing both aluminum and copper gaskets in searching, mostly seeing them on eBay and oddly seeing both in OEM packaging.

ThatYeti wrote:

Any idea which gaskets are a better option? Seeing both aluminum and copper gaskets in searching, mostly seeing them on eBay and oddly seeing both in OEM packaging.

I will leave that for the 400 guys on here to share their experience, what part number does CMNSL or Partzilla list for your specific bike ?

Partzilla doesn't have anything for it and the only one I found at a retailer was Z1 who shows it out of stock but it's the aluminum gaskets with part number OEM Ref: 11060-1242

According to Kawasaki site the exhaust pipes for the 76 and 77 models did not have the cross over pipe, but it does show this pipe for the 78 model year.  Which does show the clamps and gaskets it used.  www.kawasaki.com/en-us/owner-center/parts/142603/1978/KZ400-B1

 

Guess the new to me exhaust must be from a slightly newer bike, but holding it up to the pipes on it seems like it'll fit just fine. Do I need to worry about that crossover pipe? Saw an old post talking about how an early version that seemed to run through the engine caused leaks. This one seems like it would run underneath but I guess I could see about welding those holes shut if it'll be problematic. 

ThatYeti wrote:

Guess the new to me exhaust must be from a slightly newer bike, but holding it up to the pipes on it seems like it'll fit just fine. Do I need to worry about that crossover pipe? Saw an old post talking about how an early version that seemed to run through the engine caused leaks. This one seems like it would run underneath but I guess I could see about welding those holes shut if it'll be problematic. 

I believe what you are referring to was a passage in the head (happy to be corrected) the balance pipe in the exhaust helps torque and smooth running by balancing both cylinders - I'm not aware of any downside (probably why the factory fitted it on later models)

Any opinions on whether the copper or aluminum gaskets (crush washers) are the way to go? And any idea if one meant for a car would work, so long as it's the right size? Was hoping to get the exhaust on soonish but if I have to order the washers it looks like it's going to be weeks before I'll get them.

Cars don't use this type of sealing washer, personally I think either aluminium or copper (which ever is easily available) should do the trick (it simply needs to crush and fill any gaps between the header and exhaust port)