gsx750 gsx1000 Header and Gasket Sizes

[Guest]

Hello Everyone. I was going to make my exhaust bracket yesterday and was looking about at the rest of the exhaust and noticed the flanges seemed to be sitting away from the head a bit, thought that maybe I had forgotten to tighten the bolts up or something, long story short, I stripped the thread out of the head on one of them (no I didn't hang of the end of the wrench, it went real easy!), no big deal, I'll heli coil it, but while I was looking I couldn't see any gaskets, do they normally sit between the lip at the end of the pipe and the clamp that holds it to the head or between the pipe and the head? It was getting dark so I couldn't take them off to have a proper look, but I noticed that the pipes are stamped gsx1000, do they fit on a 750? Just need to know as I need to order parts from here and the bike is somewhere else. Thanks in advance.

[TheCafeKid]

Hello Everyone. I was going to make my exhaust bracket yesterday and was looking about at the rest of the exhaust and noticed the flanges seemed to be sitting away from the head a bit, thought that maybe I had forgotten to tighten the bolts up or something, long story short, I stripped the thread out of the head on one of them (no I didn't hang of the end of the wrench, it went real easy!), no big deal, I'll heli coil it, but while I was looking I couldn't see any gaskets, do they normally sit between the lip at the end of the pipe and the clamp that holds it to the head or between the pipe and the head? It was getting dark so I couldn't take them off to have a proper look, but I noticed that the pipes are stamped gsx1000, do they fit on a 750? Just need to know as I need to order parts from here and the bike is somewhere else. Thanks in advance.

The gaskets sit inside the exhaust port and are squished by the clamping force of the flanges when the header bolts are tightened. They're usually metallic rings with a coating of some sort on them. Many times when you remove the pipes the gaskets will stay in the head because they're bonded to carbon build up. If they're in there, they'll look like a lip just inside the exhaust ports.
You should use new ones whenever you pull the pipe technically to avoid exhaust leaks, but many times I've been lucky enough that they still seal after removing the pipe a few times.

Now, I'm going to make an assumption because you referred to the bikes as GSX1000 (katana??) and GSX750 that you're not from the USA? Here they never got the "X" added to them until they added the "R" as well. They were always just "GSwhatever"

The rule of thumb I generally go by on exhaust fitment is this:

Rear hangers not included, 8valve pipes from 750 and up will swap to 8 valve engines from 750 and up, and 16 valve pipes from 750 and up will fit 16 valve engines from 750 and up. 16v pipes will fit, port spacing wise, to 8v motors, but in my experience, they tend to hang very low on the bike. I've not tried every single combination out there however.
Also, with the 16v bikes there are some exceptions to the rule as the 83 and on 750/700 had something different and I cannot recall if it was smaller port diameter than the earlier 16v bikes or if they were not as deep... Someone else may chime in that can clarify.

But just about always, if you're using a pipe from a different model, you'll have to fabricate some rear brackets to get everything lined up in the back.

Also, I believe that 550 (8v) and 650 pipes will interchange with the same issues at the rear but will not fit larger bikes or vice versa.
Hope this helps.

[EvilEnfield]

The gaskets sit inside the exhaust port and are squished by the clamping force of the flanges when the header bolts are tightened. They're usually metallic rings with a coating of some sort on them. Many times when you remove the pipes the gaskets will stay in the head because they're bonded to carbon build up. If they're in there, they'll look like a lip just inside the exhaust ports.
You should use new ones whenever you pull the pipe technically to avoid exhaust leaks, but many times I've been lucky enough that they still seal after removing the pipe a few times.

Now, I'm going to make an assumption because you referred to the bikes as GSX1000 (katana??) and GSX750 that you're not from the USA? Here they never got the "X" added to them until they added the "R" as well. They were always just "GSwhatever"

The rule of thumb I generally go by on exhaust fitment is this:

Rear hangers not included, 8valve pipes from 750 and up will swap to 8 valve engines from 750 and up, and 16 valve pipes from 750 and up will fit 16 valve engines from 750 and up. 16v pipes will fit, port spacing wise, to 8v motors, but in my experience, they tend to hang very low on the bike. I've not tried every single combination out there however.
Also, with the 16v bikes there are some exceptions to the rule as the 83 and on 750/700 had something different and I cannot recall if it was smaller port diameter than the earlier 16v bikes or if they were not as deep... Someone else may chime in that can clarify.

But just about always, if you're using a pipe from a different model, you'll have to fabricate some rear brackets to get everything lined up in the back.

Also, I believe that 550 (8v) and 650 pipes will interchange with the same issues at the rear but will not fit larger bikes or vice versa.
Hope this helps.

Thanks, I think GSX here in the UK is the same as GS over there, I may have just been having a panic over nothing, as I really don't want any more expense, the rest of the exhaust fits fine, just making the hanger for the muffler, just that there is a gap between the flange and the head, more than I would expect to see and I couldn't see how it would be holding the pipe tight in there. I'll order some gaskets anyway but I think I'll just have to have a look at it and see what's going on, going by what you say and thinking about it now, I don't think its that bad, it may be that it was left undone while it sat for years and the studs have probably just rusted solid and wont allow it to tighten fully without stripping the head. Industrial size WD40 on order!

[7981GS]

I don't have the time for all of the what fits/what doesn't and why right now but, the blind holes in your cylinder head are already drilled about 20-25 mm deeper from the factory.
Re-tap the threaded holes deeper and use longer bolts or studs as replacements. Also good practice just to get more threads in the softer aluminum.
I recommend finding/using grade 12.9 on the exhaust at the cylinder head. (MUCH harder to break off when/if they become seized.)
The bolts or studs that are located at the frame down-tubes can be a bear to install or get nuts/flanges onto if they are too long.
Apply a small bead of Permatex Ultra Copper to the header flange ring when re-using the gaskets and you are good to go!
I have re-used the stock gaskets 30-50 times with no leaks.

Eric