Exhaust compatibility

[Guest]

Hey folks.

Will a 78' gs1000's exhaust fit a 77 gs750?

I have the 750's headers if mixing and matching are needed.

Thanks

[steve murdoch]

Are you talking about a stock exhaust or an aftermarket 4-1?
The headers from a '78 GS1000 4-1 will fit a '77 GS750.

[Steve]

Will they fit? I will have to say "yes and no".

I say that based on my experience with an 850G and a 1000G. The two bikes share just about everything except the engine, so there was a small chance that a 1000G exhaust might replace the rusting out system on my 850. Yes, the pipes fit in the ports, all the mounting holes lined up at the back, but the bolt spacing at the header collars did not fit. The bolt spacing on the 1000 is a bit wider than on the 850. If the collars were provided with slotted holes that would accomodate both sizes, then yes, it would work. Yes, I used my 850 for this scenario, but the 850 is based on the 750, with many parts interchangeable.

.

[johnyvilla]

I am talking stock exhaust here. I guess it doesn't hurt to try.

[Steve]

If you are talking about stock exhaust, I can guarantee that you will not be able to put the collars over the studs.

You will have to enlarge the hole for the studs inward to match the narrower spacing on your 750.

.

[johnyvilla]

But will the 750 headers mate with the 1000 muffler?

[Steve]

On most of the bikes I have seen, one of the pipes on each side is welded to the muffler, the other pipe slips into a Y connector ahead of the muffler. However, looking at the parts fiche for a '77 750, I see that both header pipes can slip out of the Y connection ahead of the muffler. On the other hand, on the 1000 exhaust, #2 and #3 are welded to the Y, so they are one piece from the head all the way to the rear tip of the muffler. #1 and #4 are the only ones that can be slipped out.

.

[steve murdoch]

Stock exhaust systems in good condition for both the 1000 and 750 are very hard to find.
If yours are in good shape it would be a shame to cut the mufflers off.

[johnyvilla]

Ok, thanks guys.