XJ700N Exhaust Collector-to-Can Gasket

I have one exhaust can that is a little loose and rattles a bit.

I checked the tightness on the clamp where it meets the collector and the hanger near the passenger footpeg - all snug.

Then I discovered there is supposed to be a gasket in that connection. So I went down to the Yamaha store and picked up a couple gaskets (3XW-14755), figured I'd do both sides while I'm at it. These are apparently common enough that they are still around.

The problem now is that there is NO WAY that exhaust can will fit over that gasket. The gasket is pretty thick and about the same inside diameter as the can. Fits just fine on the "male" part on the collector, but I am lost as to how the can is supposed to fit over it.

Either the gasket is incorrect or I'm doing something really wrong.

Any ideas? How the #$& are you supposed to get this thing on?

 

Unlikely I know but is there any part of an old gasket in the exhaust can?

 

Post a pic of the can and muffler and maybe we can figure it out

 

There may be, if the old gasket has hardened to the point where you confuse it for a part of the can.

 

And what happens if someone tightens the clamp full force with no gasket and then someone comes along to install what is missing? Wouldn't the muffler have to be spread back open, which would require quite a bit of force?

 

I was thinking this also could have happened.

 

Thanks everybody. I figured it out. There was, in fact, an old gasket in the can which I originally mistook for part of the can itself. Turns out the old gasket had some sort of cap that made it deceptive. The new style does not have these "caps". I'm guessing the new style is some sort of space age material that wasn't available in 1985 or something.

In this photo you can see the (destroyed) "caps" from the old gasket, along with the old gasket, sitting next to new:


As seen in the photo, the old gasket didn't exactly come out easily.

To anybody attempting this in the future: The new gaskets are relatively soft, so you have to gently insert them into the can. Do your best to clean up the cup where the gasket goes on the can as well as the output of the collector before inserting the new gasket. If you deform the new gasket too much while trying to get it into the can you won't be able to get it onto the collector output. Don't ask me how I know.

Here is a picture of the new gasket in the can, ready to be installed:


Once the gasket was in the can and everything was cleaned up and ready to go the can slipped onto the collector relatively easily.

I snugged up the mounting bolt and the clamp and it is all good now. No more loose, rattling can - which was my original problem.

I guess this is another one of those things I never thought I would have to learn about XJs, fought through the learning process, but if I had to do it again it would be super easy.

 

My bolts came off surprisingly easily, but do you have any suggestions for persuading the mufflers to part ways with the collector? Thought about maybe a couple whacks with a rubber mallet, after soaking with PB Blaster.

And did you have to take off the passenger peg to get the tab by it?

 

I had the exact same thing happen to me on my 650, old gasket was baked in there.

 

Can you apply some heat from a torch. It may expand the outer metal a little.

 

I’d thought about that. Have a hardware store run anyway, so I’ll pick up a new propane tank. Or I wonder if a heat gun would be hot enough. Thanks for getting the gears turning. The right side, which has the rattle and probably the broken gasket, seems to wiggle more than the left, but neither one of them has budged at all. I tried a few precision (and a couple not so precision) taps with the rubber mallet and also tried using the little rubber bumper mounts where the center stand lands with a socket as a drift, but neither of them have budged.

Had a few bits of rust dropping off from the collar, hoping I don’t make a bigger problem for myself than a little bit of a rattle. These are still original ‘81 cans, and aside from a couple scuffs, are still in pretty damn good shape, so I’d hate to sacrifice them.

 

If you have a heat gun you could try that first.

 

Finally got them.


Weapons of choice were a couple screwdrivers (tried using Rick's suggestion elsewhere of nails as wedges, but I couldn't figure out how to swing the hammer against them), hammer, rubber mallet, heat gun (questionable effectiveness), PB Blaster (hard to use uphill), and a LOT of grunt.



The 2 biggest things for me was a) understanding how they clamped together and that the can collars needed to be flared (whether by screwdriver or nails).



And b) knowing how much force I could apply without breaking things (YMMV). On both sides, the biggest 'ah ha, we're close!' was pushing DOWN on the end of the can, utilizing that leverage, and feeling that first 'pop' of freedom. The right side came off soon after. The left took a LOT more work.

Interestingly, in my case, the right rattled a lot more than the left, thought the right gasket is pretty fully intact and still on the collector side. On the more quiet left, the gasket crumbled, with the majority staying on the can side. Unfortunately, I'm not confident the gaskets will fix my rattle. I dumped a lot of crud out of both cans (still some to get out, but my arms need a rest), including more mouse nesting, some screening, and some other bits I don't recognize, so I question how much life these original '81 cans have left.



Anyway, they're apart and can now be buffed Tin Man-style.

 

Good job, now for the bad news: the rattle may be coming from the collector, they have a couple of baffles spot-welded internally to direct gas flow and these can weaken and fracture over time, thus becoming loose or remnants of such baffles becoming trapped within the small passages. Removing the broken-off pieces won't affect performance (too much), but getting to them might be challenging.......

Pro tip: when buying a used collector, always ask the seller if it rattles when given a good shake, and after all the rust and crud has fallen out, if it's still rattling when shaken, then there's a broken baffle inside, which may or may not be retrievable or removable.

 

With this in mind, my thought was to put them on the collector first since they fit quite easily inside my cans. Even seeing there is extra clean up to do, and doing it, these are a real bear to get over the collector stubs. The PITA on the 750 Seca is the chrome on the side of the collector. It's not like you can just whip a wire wheel around the thing. Got down to chipping away with a screwdriver and hammer like Michelangelo, and using a Dremel, but it's still kind of rough. I stopped before I munaged the first one too badly, but I'm quitting for the day. What a roller coaster.

And yeah, my originals were capped in copper on both ends and had what looked like stainless mesh inside.

 

I know this is a possibility, but I figured this had to be done to get out the collector anyway. Also, using both a mechanic’s steth while the engine was running as well as a Theragun style massager while cold (I had it in the garage to try Rick’s trick to move brake line bubbles) it really sounded like the buzz was coming from the pipe junction area, not the middle of the collector. So I have guarded hopes. I will double check with the massager before I put the cans back on.