The All Terrain R750 HT includes an air suspension fork with adjustable compression damping and lockout.
Out of the box your fork comes with 90psi which is ideal for most riders. If you find that you want a softer or firmer ride you can add or remove air using a shock pump to make incremental adjustments as needed to fit your body type and riding style. To adjust air pressure, remove the air pressure cap and attach a bike specific shock pump. These shock pumps are designed to be high-pressure, low-volume pumps to allow micro-adjustments in air pressure to help set up air forks and shocks. Once you have the correct air pressure level, you can unthread the pump and reinstall the valve cap. Keep in mind any air you hear released when unthreading the pump from the fork is from the built up pressure in the pump and not from the fork itself. It is very important not to use any other type of pump other than a bike specific shock pump. Make sure to never add more than 125psi; adding too much pressure will damage the seals and cause the fork to no longer work properly.
In addition to adjusting air pressure, you can also adjust the compression damping varying degrees by turning the lockout switch. Generally, this is the easiest and most effective way to firm up the feel of your fork when riding off-road.
You can purchase a shock pump at m2sbikes.com or from your local bike shop.