Alternative gasketing method for rear 'y' exhaust inlets

[MikeScoot]

Unlike typical Yamahas, the XZ has some weird design features. One of them is the way the exhausts attach to the rear cylinder.
UNLESS I REALLY HAVE TO I don't intend to send to Europe or the US for the 'rare as hen's teeth' original gaskets.

So, does anyone know of an alternative to get the rear 'y' exhaust piece sealed up at its inlets? I tried annealing the old ones, but they didn't cruch properly onto the 'y' piece and didn't give a tight connection.

I've considered gun putty (exhaust putty?) but that might be a pain to remove during future servicing.

Any suggestions?

Thanks,
Mike

[cvincer]

Along with the old seals that you have, use Loctite 596 high temp silicone sealer, its the only thing that worked for me.  Not sure what  'servicing'  would need  y  piece removal.   To remove the rear cylinder head means the engine has to come out of the frame, making any sealer removal easy.

[MikeScoot]

Thanks for your reply. Gladf to hear that works.
The other thing that troubled me is that the 'y' piece only inserts about 10mm into the manifold adapter pieces - the ones that connect to the head. Does this cause a bit of trouble if the 'y' isn't firmly connected?
Cheers

[The Prophet of Doom]

Blake has a whole bag of them.  You could try PMing him, else these look promising...
https://www.aircraftspruce.com/catalog/eppages/an900.php

[MikeScoot]

Thanks for the great info, Prophet. I sent Blake a PM. Also checked that website. I think the   I.D. 1-1/8   (their part no. AN900-18) ones would be the go. Is that right?
Cheers,
Mike

[The Prophet of Doom]

I've not tried myself.  Here's what Rikugun had to say...

Compared to the OEM's I measured, the 1 1/16" are the closest ID (1.0625") without being too big.  For reference, I measured the ID of a used OEM set @ 1.105" - 1.108". If you baked them in an oven they may slip on.

[Blake]

Yup I still have a lot.  I'm still clearing out boxes from my move this summer, but i'll see if i can find them.

[MikeScoot]

I've not tried myself.  Here's what Rikugun had to say...

Compared to the OEM's I measured, the 1 1/16" are the closest ID (1.0625") without being too big.  For reference, I measured the ID of a used OEM set @ 1.105" - 1.108". If you baked them in an oven they may slip on.

The diameter of the 'y' piece ends is 28mm. So the crush gaskets need to be    I.D. 28mm   or very slightly larger. I convert 28mm to be about  1-7/64" and 28.5 to be 1-1/8".  1-1/16 might be too small as it comes out at 26.9875mm. BUT maybe an interference fit is just what the doctor ordered in order to ensure they clamp up and hold the 'y' piece very firmly.

Maybe I am too concerned about all this and should just whack some sealant in there along with the old gaskets. I dunno! lololol

Mike

[The Prophet of Doom]

Maybe I am too concerned about all this and should just whack some sealant in there along with the old gaskets. I dunno! lololol

Yeah, that's what I thought on the Black Demon From Hell, but I had no luck at all with exhaust paste and the old rings.   In the end I welded the rings to the Y-piece and that helped a lot.

[kevin g]

When I got my '83 the rear had an exhaust leak so what I did was to gently tap the copper rings down a bit past the initial tapered section of the pipe and they sealed up fine when I did this.  However, I do want to replace them with new ones.  Aren't the ones from Aircraft Spruce a copper shell that has some sort of rubber inside?  If so, I don't think seals like that will work.  If someone has used the copper/rubber seals and found they work please let me know.  I think these rings have to be solid copper.

Blake, I too would like to get some of the seals from your stash.

[Blake]

Wait. Do you want the gaskets at the head( fits inside the ports), or at the end of the Y-collector?  What I have is the crush gaskets that go inside the ports on the head. It's some sort of fiber wrapped into a thin copper sheet making the ring.  It's a tight fit into the port and hasn't given me issues.  If the copper rings at the end of the wye, I have the dimensions of it somewhere/ I did find a source for them, but I never ordered them/ now don't remember where.

[MikeScoot]

Yeah, that's what I thought on the Black Demon From Hell, but I had no luck at all with exhaust paste and the old rings.   In the end I welded the rings to the Y-piece and that helped a lot.

lolol I'll see how I go with gaskets and goo, but if it causes too much mucking around I might do it your way.
There must have been a bit of LSD floating around in Japan at that time 'cos that rear exhaust set-up is one of the weirdest things I've seen on ANY Japanese bike.
Thanks for the tip.

[MikeScoot]

...  Aren't the ones from Aircraft Spruce a copper shell that has some sort of rubber inside?

I think they are copper-wrapped asbestos - same as the original part. They look to even have the same hexagonal section.
Cheers

[MikeScoot]

Wait. Do you want the gaskets at the head( fits inside the ports), or at the end of the Y-collector?

Thanks, but I'm after the ones that connect the Y-piece to those funky (@#$%&*%$#@) adapters that fit into the rear head. Different part altogether.

I reckon I'll try some of that Loctite 596 high temp silicone sealer stuff [thanks for the tip, Cvincer] - as long as it has a reasonably short curing time. The last lot I used on a car's exhaust heat shield was a differnt brand and took about a month to cure.

Cheers,
Mike

[MikeScoot]

Wait. Do you want the gaskets at the head( fits inside the ports), or at the end of the Y-collector?

Thanks, but I'm after the ones that connect the Y-piece to those funky (@#$%&*%$#@) adapters that fit into the rear head. Different part altogether.

I reckon I'll try some of that Loctite 596 high temp silicone sealer stuff [thanks for the tip, Cvincer] - as long as it has a reasonably short curing time. The last lot I used on a car's exhaust heat shield was a different brand and took about a month to cure.

Cheers,
Mike

[The Prophet of Doom]

Wait. Do you want the gaskets at the head( fits inside the ports), or at the end of the Y-collector?

Thanks, but I'm after the ones that connect the Y-piece to those funky (@#$%&*%$#@) adapters that fit into the rear head. Different part altogether.

I reckon I'll try some of that Loctite 596 high temp silicone sealer stuff [thanks for the tip, Cvincer] - as long as it has a reasonably short curing time. The last lot I used on a car's exhaust heat shield was a differnt brand and took about a month to cure.

Cheers,
Mike

Mike,
how did you get on with the Loctite 596?
I'm doing the exhaust now and like yours the copper rings are too loose to get a grip on the Y-pipe.  Damned thing just pulls out again.
I was hoping to avoid welding on this one as that means getting a $350 argon gas re-fill.


28mm ID copper o-rings are not available anywhere

[MikeScoot]

lolol, yeah, wonderful setup eh! lolol
I don't think I used the Loctite stuff - I think it was Permaset, but still high temp silicone stuff (red too). Seems to have workd well, but I have done only a couple of K's on the bike - literally. I hav no reason to believe it will not hang in there though. Letting it set a bit in place before tightning-up is a good idea. Also, If you have the motor out of the bike that's the best time to do it!
Supporting (chocking upward) the fool thing while bolting the mufflers on is a VERY good idea too!