For serious and fun minded motorcycle riders in the Greater Texoma area and beyond.

A failure in the 90-degree valve stem used in the GL1800 front and rear tires can cause air leakage during riding. This problem was noted by Danny Newton on a trip and caused a considerable amount of problems at first.

Danny noticed his tire pressure was leaking down. After several attempts to find the source of the leak, he removed the tire and immersed it in water. Not detecting any bubbles Danny replaced the tire and continued to ride. The pressure continued to drop. Although he had one of the cleanest tires in town, it was not evident why the pressure was not holding properly.

Then Danny took a closer look at the valve stem. Keep in mind, there were no leakage bubbles detected with full immersion - and that included in the area of the stem.

Applying a little pressure to the stem, the source of the leak was finally revealed. The stem had failed - but not while the tire and wheel were at rest. The leak would occur during riding. Apparently the dynamic forces involved with the rapidly rotating wheel were enough to cause a distortion or displacement of the stem - causing a 'dynamic' leak while the wheel was rotating.

If you are experiencing a slow - or not so slow - leakage from you tire, pay careful attention to the stem. It might be a good idea to have the entire stem replaced when mounting a new tire. After all, that is standard procedure in automobiles. The small added cost of a new stem is more than offset by the possible benefits - such as avoiding a road mishap.

Make sure when you check the air pressure or fill the tire that you press on the BACK side of the valve stem with your finger to counter-act the pressure of the tire gauge or the air chuck to relieve strain on the valve stem assembly.

Also insure that the stabilizer bracket that holds the stem in place is properly seated on the rim. This bracket or 'brace' helps protect the stem from being displaced by centrifugal forces thereby staving off failure under the stresses of normal riding.

And as always, check you air pressure before each ride.