My understanding is the metal screens keep any material from passing thru the engine, side to side, in case of a clutch failure or stator failure or gear case failure. They don't need to be cleaned every oil change and shouldn't have any thing in them.
If Yamaha makes a wrr450 it will probably be heavier than the 610/630, and with cheaper parts.
On the 630 you remove the fuel tank, 1 bolt and a couple hoses and you just remove 2 bottom bolts and push the radiators forward to remove the valve cover. Once you do it once its a 15 minute job to check valves.
My Husaberg was about the same after you removed the tank it had 2 small covers to remove to check valves.
XT, NX, KLX, KLR, DR all long gone.
rickcj7 screwed with this post 01-04-2013 at 11:41 PM