Hi Factor,
I also have a 2000 FE401E. I replaced my OEM '55' cam at 224 hours, because the intake lobe became badly pitted.
I had replaced OEM cam follower bearings at intervals of 62.4 hrs, 67.9 hrs, and at another 91.1 hrs replaced the rocker arm assemblies with 2003 rocker arms. The 03 arms have a smaller axel for the roller bearing to ride on, permitting the use of larger diameter roller needles. They last much longer than the OEM design used up to 2003. The 2nd replacement at 67.9 hours was with Husquvarna am follower bearings, which had been noted as lasting longer.
The bike then ran another 99.3 hours with the 2003 rocker arms before I pulled the cam cover to check and found that the intake follower bearing had worn 0.1mm on the axel like your picture shows and also grooved the arm like yours pictured. I dressed the arm with a file, and put in a new roller assembly.
So, one might take this limited data to mean that the 03 (in my case) lasted 1 1/2 times as long as the original 2000 design.
You can use a less violent cam ramp design (like Dale's) to reduce the acceleration forces on the cam lobe and the cam follower bearing , but you will still have the very heavy spring forces due to the Husaberg conical spring design. The spring design is limited by the head and head cover design. If there was space available, or if you used a different spring material, like titanium, the spring could be redesigned to provide lower forces (using Dale's cam designs) and this would increase the time between replacement of the valve train components significantly.
Husaberg now puts titanium valves, different springs and valve guides in the 2005 450 FC and FS-C motors. I have no idea as to what the difference is in the spring rates or what the new springs are made of, I would guess titanium.
You can see pictures of my pitted cam lobes and worn cam follower bearing axle in my Gallery.
Regards,
Joe
uke:
