Tools
Guest
I cut the hole in my 7720 10 yrs ago,made it 30 in. wide x 20 in. high.Stared at the bottom where the tin overlaps the cross auger tin, went up,over and back down,had to cut thru a reinforcing piece of triangle tubing that goes across the grain tank on the outside,I took the pipe off from the air filter that goes across inside the tank to make it easier to do this mod.I cut it with a torch.I then used a sheet of 1_8 thick steel to cover it,i welded a handle on it to aid in lifting it out,drilled holes in the corners and three down each side and across the top and used self tapping 1_4 in. screws to bolt it down.You have to use a fairly heavy piece of steel for the cover becouse once you cut the hole and the cross brace underneath, the tank tin is kind weak.With 1_8 sheet steel you will never have any problem.Once you put the air intake pipe back in you cant get the new cover out,there isnt enough room but you can slide it to one side and up a little to uncover the hole.Makes it easy to clean out under the tank and like you say can clean the straw and chaff away from the seperator clutch lever mechenisiom.I often thought to reroute the air intake pipe higher up then one could remove the cover completly and have lots of room to get in there.But you know its one of those things were you only open it up once or twice a year and when you do your kind of busy so you dont do it. If i was to do one again i would move the pipe while i was building this mod.I might even do it yet.