You can replace the rocker arms yourself, and the manual does have a procedure for this. You will need to purchase a tool to compress the valve spring while still on the head. It wraps around the cam and allows you to push on the valve spring to get the rocker arm out of there. You will rotate the engine around until the cylinder you are working on is at TDC, (valves shut). I see no way to cheat without buying the tool. I bought one, and it still was work to do it.
1989 560SEL (172k)
1989 325IC (122K)
2004 Suzuki Volusia LE (3500 miles)
2005 Yamaha Road Star (20 K miles)