Is my exhaust supposed to have a crossover pipe? '78 KZ750 Twin

Seems like every KZ750 Twin exhaust pic I've seen shows a crossover pipe on the exhaust (the service manual I got even references one), but my bike doesn't have one.

Is it supposed to have one?

Yes, the stock exhaust on the 750 twins has a crossover pipe.

Maybe you have a MAC two into two exhaust.

If it's the bike in the picture, that's not a stock exhaust.

Well, I knew the mufflers weren't stock...didn't think the pipes weren't stock either. Weird.

The mufflers on the bike don't look like the ones that MAC has with their kit. The mufflers also look way newer than the pipes.

Is there any disadvantage to not having a crossover?

That also makes me wonder if maybe the carbs have been jetted...hmm.

I doubt that removing the crossover is going to have a noticeable effect on the jetting, and you may or may not be able to detect the difference performance wise.

Not a huge deal, just ride it and enjoy

The crossover helps wth the lower torque. It will balance the pressure of the exhaust pulses in the system. The H-pipe equalizer allows some of the excess pressure to bleed over to the 'quiet side' of the exhaust system, resulting in some low and mid-range torque improvements. At high RPMs, however, in traditional exhaust systems, the gases cannot bleed across the H-pipe fast enough to help power significantly. Performance systems with the H pipe design, attempt to over come this by using a shorter cross over pipe which is also slightly larger in diameter as the main exhaust.

steell wrote:

I doubt that removing the crossover is going to have a noticeable effect on the jetting, and you may or may not be able to detect the difference performance wise.

Not a huge deal, just ride it and enjoy

I meant the jetting might be affected by the fact that it has aftermarket pipes without a crossover AND some sort of aftermarket mufflers on it (that are definitely louder than stock)

I have a cross-over on one of my 750's and not on the other.

The one with the cross-over has more low-end power... how much I cannot measure, but enough...

...enough that I have decided to add a cross-over to the other...

Take the plugs out and look at them, that will tell you if there's a jetting problem.

But as long as you have the stock air box and filter on it, I doubt that re-jetting was or will be, needed.

I've swapped stock exhaust for two into one MAC pipes, and then swapped back, and never had a problem, but others may have different experiences.

When I bought my bike, in the '90's, I didn't know anything about a crossover pipe, until I did an oil change and had to look under the bike. I then discovered a large hole on each, of the 2 headers, w/some rusted metal attached. Rode the bike for around 3 yrs before it was "garaged" for 12 yrs, never noticed a bit of problems w/torque, low end or high. I now have Mac 2-1 and maybe my memory is shot, but I can't tell any difference. Still has more low end torque than is expected.

ronjones wrote:

When I bought my bike, in the '90's, I didn't know anything about a crossover pipe, until I did an oil change and had to look under the bike. I then discovered a large hole on each, of the 2 headers, w/some rusted metal attached. Rode the bike for around 3 yrs before it was "garaged" for 12 yrs, never noticed a bit of problems w/torque, low end or high. I now have Mac 2-1 and maybe my memory is shot, but I can't tell any difference. Still has more low end torque than is expected.

I have the MAC 2-1 on my twin and as I recall, the stock pipes did have more low end pull. It was strong all the way down to about 2K. Now it's soft in between about 2k and 2.4k. Still has pretty good pull, just not as good as the stock pipes.

do you know where i can find any of these exhaust