Carburetor Rebuilds and Cleaning

Carburetor rebuilds stemming from late-model gasohol turning to stinky varnish are a weekly occurrence in many of the Thai motorcycle service departments, at least in the area I live. The ethanol in the gasohol fuel dissolves materials like rubber, plastic and fiberglass. Left to sit long enough, the varnish turns to tar and no amount of soaking jets in carburetor cleaner will unplug them.

But in a pinch, if you have a bench grinder with a wire wheel at one end, pull a strand of wire out with pliers and it's the perfect size for poking through the tiny hoe of pilot or idling jets. Then again, a bass player buddy of mine swears by guitar string for brass jet reaming.

But the very best way to deal with clogged carburetor jets is found in hardware stores, on the welding section shelf. A set of welding tip cleaners has a range of wires that are just perfect for motorcycle-sized carburetor jets. The last set I picked up cost a few hundred Baht. Remember: just because you can see light through a jet doesn't mean its hole size hasn't been reduced by varnish buildup. I recall a older motorcycle that drove me crazy because it wouldn't pull from the midrange on up, feeling like its main jets were 10 sizes too small.

The mains were correct for that model and looked perfect under a magnifying glass. I held them over a white sheet of paper and ran a wire through them in a scraping action. I saw fine, powdered gook fall out, restoring the hole to full size. That old motorcycle ran great after its hardened arteries were cleaned.