bad rocker arms -400ex
#1
02-18-2000, 09:37 PM
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Has anyone been hearing about their rocker arms wearing out on the 400? I am in the process of putting in the 440 kit in mine and did notice some discoloration on the surface of the cam and the rocker arms. Is this normal or not? My quad is a 1999 model. Shops have been telling me to get the rocker arms hard faced but then Honda said they have not heard of any bad rocker arms. So what do I do, put in the 440 kit and leave the stock rocker arms in, (worn) or do I send them in and get them hard faced? If I put in the worn rockers I will keep the stock cam, but if i get the rockers hard faced I will put in a mild cam. And also has anyone tried puting in the xr400 dirt bike cam in their quad and if so did you leave your rocker arms alone. Please help!
#3
02-19-2000, 08:47 PM
Discoloration is a condition typically caused by overheating due to a low oil or poor oil condition. If the surface appears "blue", the engine has had some oiling problems sometime in its past, or currently.
As far as "bad" rockers go, the rockers on the 400 aren't bad, they're just under lots of pressure. The Honda RFVC (Radial Four Valve) head uses a kind of weird design which utilizes 4 main rockers, then 4 sub-rockers (which you already know, since you disassembled it!). Anyway, this design puts more pressure on the main rocker and cam lobes than a regular design. The pressure is increased exponentially when you add lift and duration to the cam (especially lift). This is why hardfacing is recommended when you go to a higher lift cam.
The thing is, hardfacing the rockers won't keep the metal from overheating -- so it's really important to make sure the problem was transitory (such as someone running crummy oil or not enough of it), and not an ongoing problem with the oiling system itself.
After you've determined that the oiling system is okay, I'd go ahead and hardface the rockers you have, as long as the shafts and the area of the rocker that the shaft goes through aren't scarred up from overheating.
Hope this answers your questions!
As far as "bad" rockers go, the rockers on the 400 aren't bad, they're just under lots of pressure. The Honda RFVC (Radial Four Valve) head uses a kind of weird design which utilizes 4 main rockers, then 4 sub-rockers (which you already know, since you disassembled it!). Anyway, this design puts more pressure on the main rocker and cam lobes than a regular design. The pressure is increased exponentially when you add lift and duration to the cam (especially lift). This is why hardfacing is recommended when you go to a higher lift cam.
The thing is, hardfacing the rockers won't keep the metal from overheating -- so it's really important to make sure the problem was transitory (such as someone running crummy oil or not enough of it), and not an ongoing problem with the oiling system itself.
After you've determined that the oiling system is okay, I'd go ahead and hardface the rockers you have, as long as the shafts and the area of the rocker that the shaft goes through aren't scarred up from overheating.
Hope this answers your questions!
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