[Made in England]
Help 49: Got the Blues?


The chrome exhaust pipes on British Bikes are prone to turn blue. Heat is responsible, but why? Limeys are prone to bluing due to a few factors. Contributing factors are the thickness of the metal, the quality of the plating, the distance from the port to the bend in the pipe, and radius of the bend in the pipe.

Hot gases from the cylinder enter the pipe where they cool rapidly. The greater the distances to the first bend, the cooler the gases and the less discoloration you will get on the chrome.

The thicker the metal the greater the cooling effect, so again there is less discoloration. The sharper the bend, the more resistance there is to gas flow so, instead of moving quickly down the pipe, the hot gases hang around for a while, hence more heat and discoloration.

Too much blue may indicate that there is a fault. An exhaust valve hanging open or adjusted incorrectly may increase the exhaust heat. The there is also the possibility that the exhaust gases are hotter than they should be, due to a weak mixture or retarded ignition setting. This added heat exaggerates the blues. It is a popular assumption that a blue pipe is an indication of a hard rider. There is little evidence to support this view.

The average consumer does not have control over the quality of the plating, the distance from the port to the bend in the pipe, and radius of the bend in the pipe. Dual wall pipes are not available for British bikes. The thickness of the metal may be changed. An expensive alternative is to have a ceramic coating bonded to the inside of the pipe. The pipes are then re-chromed. This costs more then the cost of a new set of pipes. A small company call Cool Pipes in Indialantic, Florida performs this service.

What can you do if you have the blues? Once discoloration occurs it can be removed using commercially available products like Blue-away or Blue-Buster. These products are mildly abrasive, so after several applications the mirror finish of the chrome becomes satin-like, so the best way to deal with blueing is to prevent it or cover it up.

A low cost alternative to this is a coating that an individual can apply. I experimented with a coating for the inside of the pipes that is supposed to eliminate the blues. The manufacture Dyno Kote has a Pipe Blueing Preventative Kit. The manufacture recommends that it used only on new pipes. I have used this product on both new and old pipes, after a thorough cleaning. I have had good results so far with both.

The Dyno Kote kit comes with a brush and solvent. After applying the coating as per the directions, the pipes should be baked so the coating cures completely. A regular household oven works fine if you let the ends of the pipes hang out of the door and bake at 150 degrees for about 20 minutes, or at the temperature and time specified. I have seen pipes coated this way cut in half as a demonstration and the coating stays intact. The ceramic coating is highly insulative, much like the ceramic tiles on the space shuttle and will insulate the metal pipe from the hot exhaust gas.

Keep it in the saddle!

Mike


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