Exhaust fitment issues.

Hi guys,
I’ve been trying to piece together a project 1984 GPZ750.
Having a hell of a time with the exhaust.
I bought what I think is a V&H header and centre pipe, I believe from a older KZ.
It utilizes the collar and half-round pieces, but it doesn’t seem these work with my engine.
I’m ready to buy a new exhaust, I’d be half way there with the $ I have into this other stuff.
I don’t want to throw away more money before getting more info.
Thanks for reading and any suggestions.

So, this could be from a KZ550 or a GS1000 or a 650 Fazer?

So is this a complete waste of time?
The centre pipe is about 2-1/2” diameter.
Everything I’ve found about a GPZ750 says it would be about 2” or 51 mm.

Where did you get it?
Steve

I got it from a wrecker in Ontario.
I don’t want to publicly de-fame him, but everything I got from him was useless...

Im not sure you can take the pipe diameter as a marker. Ive heard (rightly or not) that the Delkevic downpipes are quite narrow while my Harris downpipes are porky little buggers. The size of the flange where the pipes join the engine would be the important part.I would think. Then you have to think about the position and angle of the bends and the distance in between them. Im sure theres other stuff as well.
P.S. Im pretty sure my Harris originally came off a GPZ 750. Fits my CSR1000 no problem.

Meat-head wrote: So is this a complete waste of time?
The centre pipe is about 2-1/2” diameter.
Everything I’ve found about a GPZ750 says it would be about 2” or 51 mm.

That depends on a lot of things.
Here are my opinions. Keep in mind what you paid for them.

If it does not fit, do not use it.
If it does fit and performance is not a priority and you are pretty sure you can get a mid-pipe and muffler to fit and you like it, use it.

There is much more to a performance exhaust than looks. The relationship between primary pipe diameter and length is very important to assuring the best scavaging in the fat part of the power band. The diameter and length of the collector is also very important.
A bunch of years ago I ran across an old magazine article comparing a bunch of aftermarket exhausts on a stock KZ1000. One of the systems was a very expensive Yoshimura racing system. It was clearly designed for modified engines operating at high rpm. On the stock engine it made less power in the mid range than the stock exhaust system did!

I have the centre pipe, but am having a hell of a time figuring how to couple the header to the engine. I ordered some collars for an older 750 but they don’t work.
I think I mentioned it earlier, but I’m half way to a new complete exhaust, with what I have into this.
I am hoping someoyelse has been down this road and has some good tips. I’m ready to say screw it and buy a new one. But there are few guarantees that the new one will be better.
For me shopping on line has been about 50% successful.

Do you have a set of these?

Maybe you need longer half split collas, my collas were made from stainless steel

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Yours look like late shorter GPZ half split collas like Nessim

I have a set from a KZ. They don’t work.

Am presupposing that the pipe flanges align with the exhaust ports, but that the pipes won't tighten into position because the split collars at hand are either too wide or too narrow.

Is there some other fitment issue besides width of the split collars?

Correct split collar width will properly compress the gasket just as the clamp meets the head when tightening the nuts onto the studs.






Good Fortune!