From:Dave Hennessey
Subject: Constipation Date:Sat Oct 19 12:03:32 2013
Response to:18861
The owner's manual says that you should de-carbonize every 5000 miles or sooner. But most people never bothered, and ran the bike until it stopped running. 50 years later, you inherit a bike that is totally constipated...

The first thing to do is to remove the muffler. First, measure how much the back end of the center tube protrudes from the outer body of the muffler, so you can reassemble it the same amount.

The muffler's probably been attached to the exhaust pipe for 50 years, so it might be easier to take off the muffler and pipe together, go outside in the grass, and separate the muffler from the tailpipe there.

Put a 2x4 on the ground, and whack the back end of the muffler on it - this will drive the center tube out of the front of the muffler body. The center tube has about 100 holes in it. Undoubtedly, some or most of them will be plugged up with carbon. Take a Phillips screwdriver or similar, and clean them all out. Do what you can to clean the inside and outside of the center tube (yes, there's a baffle in the middle of it), and the inside of the muffler body. It's a dirty rotten - but necessary - job.

Stick your finger into the exhaust port. The port gets smaller - the actual hole in the cylinder wall is a much smaller rectangular opening. You should be able to poke your finger into the cylinder. Try not to knock any carbon loose during inspection - you don't want it to fall into the cylinder. You could try removing the spark plug and shining a flashlight into the plug hole, then looking into the exhaust port, but I'm not sure how successful that would be.

If the exhaust port is really clogged with carbon, you need to remove the head, cylinder, and piston and give them a good cleaning. That gets rather involved, so if the port isn't too bad, put the exhaust system back on and see how the bike runs then.

With luck, it'll run much better, and you'll get some riding in before it gets really cold out.

Sooner or later, you will need to remove the head, cylinder, and piston for cleaning. This is not rocket science, you just need to follow the directions and work slowly and methodically. It's NOT a one-afternoon job. The only oddball tool you need is a snap-ring pliers to spread the piston pin lock rings. Sounds like a job for those cold winter months.