All-terrain vehicles use relatively low tire pressures for added traction. Occasionally, even at this low pressure, ATV tires will develop slow leaks. A slowly leaking ATV tire may lose a pound or two of air over a period of weeks. You can repair these slow leaks either as a do-it-yourself project or by taking the tire to an ATV or tire-repair facility. The first step for the do-it-yourselfer, often the most difficult step, is to find the exact location of the leak.
Examine the tire tread and sidewalls for any indication of puncture, cracking or tread separation. You can patch a puncture to the tread; but you usually must replace tires with punctured or damaged sidewalls. If there is no visible damage to the tread or sidewalls, proceed to the next step.
Unscrew the valve stem cover and determine whether the valve stem is leaking. Spray a small amount of soapy water over the valve stem. If you see bubbles, the valve stem is leaking. If you do not see bubbles, skip to Step 4.
Use the pointed end of a valve stem tool to let the pressure out of the tire. Then insert the wrench end of the valve stem tool into the valve stem, and tighten the stem if loose. If the stem does not appear loose, remove the stem and replace it with a new one. Replacement valve stems are available at most auto parts and tire stores, and most tire stores will replace the stem for a nominal charge.
Spread a film of soapy water around both inner and outer beads. The bead is the sealant applied between the rim and tire when the tire is mounted. If you see bubbles at the bead, you have identified the leak. Occasionally this leak is caused by a small grain of sand or dirt having worked its way into the bead. Brush the area vigorously with a stiff-bristled brush and allow the tire to sit for a few minutes. Test again with soapy water. If the brush removes the sand or dirt from the bead, the tire may seal itself after the particle is removed. Deflating and reinflating the tire may assist in this resealing.