How do you clean out mufflers with caustic soda?

[Fontain25]

Spark plugs are turning black on 71 Ambassador. Has good blue spark and carbs operate very nicely. No leak down and compression is good. With mufflers on it was very muted, so I removed them and installed new plugs - went for about 20 mile ride and checked plugs - clean. Want to clean mufflers out and only way I've read about is with caustic soda but I don't know how to plug outlet of muffler or how much soda to use? If you know of other methods to clean mufflers i'm all ears. Or should I just replace them?

[Idontwantapickle]

Spark plugs are turning black on 71 Ambassador. Has good blue spark and carbs operate very nicely. No leak down and compression is good. With mufflers on it was very muted, so I removed them and installed new plugs - went for about 20 mile ride and checked plugs - clean. Want to clean mufflers out and only way I've read about is with caustic soda but I don't know how to plug outlet of muffler or how much soda to use? If you know of other methods to clean mufflers i'm all ears. Or should I just replace them?

A little more information please? Have you checked the points and the timing? Although the mufflers can clog it would be an unusual failure compared to many other causes of sooty or oily plugs. Removing the mufflers may have merely masked the symptom, plug color, of the problem.
Hunter

[Fontain25]

Yes , new points and condenser and timing has been set. Mufflers are OE and bike had set for many years. New plug wires and caps. Combustion chamber has been decoked.

[guzzisteve]

Simple, run w/no mufflers all the time, I use 36" fishtails.

[John A]

The mufflers may be mechanically closed by an internal failure due to corrosion. I've never cleaned a muffler with caustic soda but I doubt it's going to be worth the trouble

[Old Jock]

That takes me back

About 45 years ago that was a method used to de-carbonize coked exhausts on 2 strokes and some 4 strokes. I did it a couple of times.

We went to the hardware store and got caustic soda for drain cleaning, mixed according to the instructions plugged off the pipes at one end, I think I used rubber bungs.

Poured in and swished around and let it sit for 10 minutes or whatever not long, the instructions told you.

Cleaned out with lots of fresh water then went for a ride.

Sociable it was not the exhausts were blowing bits of carbon out for miles, they looked like smuts that you get from coal fire powered station. only a lot bigger and a lot more

I'd be very wary about doing it on cans now, surely there have to be better products or methods out there?

[Fontain25]

Thanks for the replies. Went another route - sharpened the tip of a lady-slipper pry bar and pounded four 1/2" holes into each baffle [there is only one baffle in muffler]. That oughtha do the trick for now! After reinstalling mufflers and taking it for a test ride I'm satisfied that the pipes are not too loud and the bike runs better in general and spark plugs are normal color. Thanks.

[wirespokes]

Perhaps a mouse or rat died in its nest in there. Caustic soda would have helped with that.

[canuck750]

For the two stroke bikes I ahve restored I bought a four foot length of 10" diameter PVC drain pipe, capped one end and fitted a screw cap on the other, put my muffler in the vessel and filled it up with Draino.

This pipe contraption also works good for immersing mufflers in Evaporust.

[wymple]

If you are talking about carbon why not just cap the muffler, stand it on end and fill it with water overnight? Water dissolves carbon, we used to soak pistons overnight and then just shake the carbon off. Put the mufflers back on and I'd think a big black cloud of carbon would pour out for a bit.

[Sasquatch Jim]

  Pour in caustic soda and reach inside to scrub with a small wire brush.  Oh, and wear rubber gloves.

[Don G]

Check out the yellow pages for automotive machine shops in your area, one may still have a hot tank for cleaning engine parts.  DonG