How to "Properly" Install Muffler Gaskets

How Do You "Properly" Install Muffler Gaskets??

Hello Everyone, this is my first post on this forum. I have used this website many times in the past and it has been very helpful, but I could not find anything specific about what I am currently working on. Hopefully someone can help me out.

FIRST OFF: I was having some issues with shifting from first to second gear, so I took the bike apart and it turned out to be the shift forks. Now I am putting the bike back together and I am trying to get the exhaust back on and I am having some issues with the muffler gaskets. You know; the silver, cylinder shaped gaskets with metal mesh in them. (before anyone asks, OEM all the way)

ABOUT THE BIKE: The bike is a 1991 ST1100, with no mods about 60k miles on it and the exhaust has never been removed before.

MOVING FORWARD:
The service manual says to just install them... but does that mean that I put the gaskets IN the exhaust and then put the mufflers and right exhaust in... OR does that mean put the gaskets ON the mufflers and right exhaust and then put them in?

I tried to put the gaskets IN first, and when I was installing the right exhaust I totally messed it up. Also, I know for sure one of the mufflers is already going to be jacked up.

The old gaskets were difficult to remove but I cleaned them up as best I could.

When I put them in the exhaust, they did not want to go in, but I was able to press them in (to be flush with the exhaust) with a piece of 2x4. not sure if that was the right thing to do (well obviously not since I am writing this post.) I was thinking about maybe loosening the clamps all the way and stretching the exhaust out a bit, figuring that when the clamps where tighten, it would all come together. Or maybe use some WD-40... or something.

Any tips, tricks or advice would be greatly appreciated. Please take a look at the attached pics to view my "handy work".

Best,
Red

Re: How Do You "Properly" Install Muffler Gaskets??

I have a 1993, and have exactly the same issue. I have just stormed upstairs for a rant, but will not lower myself to swear on this site !! I cleaned the collector side ok, and the first seal went in tight but flush, and still looked in one piece. I then gentle presented the silencer and started a slight wiggle to ease it in.
all untangled and started to unwrap.
With the other new seal I gently slid It over the new silencer side, again it was tight but it split the seal and a whole world of hate began.
Did you solve your problem?

When I was changing gaskets last year on my 94 I got same dilemma. What I did was, I loosened the clamp all the way, opened those four sides under the clamp with pliers and pushed the gasket into collector as straight as possible. Than I started pushing muffler in slowly while rotating it back and fort. It scraped off a bit of gasket but after install all bits got spit out when I started the bike. The whole exhaust has been solid ever since.

Mark

Re: How Do You "Properly" Install Muffler Gaskets??

Red024 said:

The service manual says to just install them...

Click to expand...

LOL! Yeah, that's a good one... :lol:

I've 'mutilated' an old screwdriver on the bench-grinder to serve as small chisel, bang it in between pipe and gasket, and brake those old graphite-bushings into pieces...
Once they start to crumble, you can grab the steel mesh inside with a pair of pliers and rotate/twist it together, braking the rest off/out.
I then use an old gasket scraper to clean the inside of the pipe, after that the cordless drill with a wire brush (slightly bigger then the inner diameter if the collector stubs), for the final cleaning. Warning: wear safety goggles!

Then I smear a good layer of the good old copper slip on the inside of the stubs, before I push the new gaskets into place.
Same on the stubs of them silencer, the high-temp lube aids the assembly process tremendously and (I hope) it'll also make any future disassembling a lot easier.

Then the clamps (which I'd taken off completely as first step of the work):
re-cut the threads of bolts and the welded nuts (and bore out the ones that have snapped off ;-) ), smear another layer of copper slip on the outside of the collector tube-end as well as on the inside of the clamp, bend it over and in shape by using water pump pliers; then more copper slip on the bolt-threads and tighten them evenly.
Then I apply another layer of my copper lube on the, now blank threaded ends of them bolts, so I can open them again in two or three years from now.

I further 'service' those clamps on every occasion the rear wheel comes out by cleaning them (especially the bolt ends) with a small wire brush and a good layer of copper-spray for conservation.

Re: How Do You "Properly" Install Muffler Gaskets??

An exhaust pipe expander is your friend here. It is a hand held tool and when tightened on the i.d. of outer pipe prior to install will make everything slide right back together like new. Much cheaper than messing up those expensive gaskets.

Re: How Do You "Properly" Install Muffler Gaskets??

I think my problem is sorted ! Having spoken at length with the very nice man at Motad, it turns out that the silencers I had been supplied came out of the factory the wrong size. So they should be 42mm OD, but mine was 43.25mm and no wonder the gaskets got messed up. Once this was understood they replaced the silencers and new seals overnight delivery. Can't fault the after service! Will have a go at fitting tomorrow but the gasket slides on the silencer smooth.

Re: How Do You "Properly" Install Muffler Gaskets??

Tommo said:

...Motad...

Click to expand...

That minor fact was kept secret in your opening post/original inquiry ;-)

Besides expanding the header pipe little, I used a thin film of anti-seize on the inner and outer surface of the gasket installing them. It seemed to help a lot to seat all the components.