Jinzo Ningen
Well-Known Member
- Joined
- May 27, 2011
- Threads
- 44
- Messages
- 127
One of the basic improvements that I wanted to make to my newly-acquired GH 721D was to make it as quiet as possible. Luckily, I happened to have 2 good-sized pieces of Dynamat sound/heat absorbing material sitting in my garage that was leftover from a Jeep hood project. I took one of the sections and trimmed it down to fit the main area of the center pulley/spindle deck shield on my #9572 / 72" deck. (I had to piece together 4 little odds-n-ends to fit the narrow top most section.)
Next up was to scrape off the narrow, thin foam rubber strips that were installed by Grasshopper to reduce metal-to-metal noise between the center deck shield and the support strut deck frame arms. Those puny little strips may have worked when they were new, but after 14 years they were compressed paper-thin and were pretty rigid/brittle. I bought some weatherstripping foam and after cleaning off the old strips' adhesive with GooGone I applied the new pieces. They're almost 5mm thick, so the center shield is very snug now when latching it into place. I took an Xacto knife and trimmed them to exactly fit the shield's contours. The foam strips will compress some over time but they're thick enough that even compressed 50-75% they'll still prevent the deck shield from coming into contact with the support strut arms. I placed some thick rubber adhesive squares I picked up where I work and glued them spaced more or less evenly along the front section of the center shield where it lays over the support arm cross member, so that that area is also insulated from metal-to-metal vibration now.
The last thing I did was install the remaining chuck of Dynamat under the 'Hopper's engine hood. As you can see in the pics of taken from the left & right side, looking up underneath, I had to do a bit of trim work, cutting a slot to allow the coolant overflow hose bracket to pass through and trimming around the pass through hole for the oil fill.
While the dB noise levels are essentially the same it is now routed lower, coming out from the sides; no noise coming up through the hood. It's kinda hard to explain but to get the basic concept just put your hands behind your head at the base of your neck and clap. Now drop your arms down to your sides and reach around behind your rear end and clap. The noise being routed farther away from the operator's ears makes a big difference if you're exposed to it for any length of time. Just 3-6dB can be a HUGE difference. I still wear ear protection when mowing and always will, but these 2 sound dampening projects have really helped make being on the Grasshopper more pleasant, especially if I have to mow the entire lawn & property in one afternoon.
Next up was to scrape off the narrow, thin foam rubber strips that were installed by Grasshopper to reduce metal-to-metal noise between the center deck shield and the support strut deck frame arms. Those puny little strips may have worked when they were new, but after 14 years they were compressed paper-thin and were pretty rigid/brittle. I bought some weatherstripping foam and after cleaning off the old strips' adhesive with GooGone I applied the new pieces. They're almost 5mm thick, so the center shield is very snug now when latching it into place. I took an Xacto knife and trimmed them to exactly fit the shield's contours. The foam strips will compress some over time but they're thick enough that even compressed 50-75% they'll still prevent the deck shield from coming into contact with the support strut arms. I placed some thick rubber adhesive squares I picked up where I work and glued them spaced more or less evenly along the front section of the center shield where it lays over the support arm cross member, so that that area is also insulated from metal-to-metal vibration now.
The last thing I did was install the remaining chuck of Dynamat under the 'Hopper's engine hood. As you can see in the pics of taken from the left & right side, looking up underneath, I had to do a bit of trim work, cutting a slot to allow the coolant overflow hose bracket to pass through and trimming around the pass through hole for the oil fill.
While the dB noise levels are essentially the same it is now routed lower, coming out from the sides; no noise coming up through the hood. It's kinda hard to explain but to get the basic concept just put your hands behind your head at the base of your neck and clap. Now drop your arms down to your sides and reach around behind your rear end and clap. The noise being routed farther away from the operator's ears makes a big difference if you're exposed to it for any length of time. Just 3-6dB can be a HUGE difference. I still wear ear protection when mowing and always will, but these 2 sound dampening projects have really helped make being on the Grasshopper more pleasant, especially if I have to mow the entire lawn & property in one afternoon.