700 ves exhaust valve trouble

I'm working on a friends ves 700 rmk. At idle it has a rattle that seems to be coming from the exhaust valves. Pulled the valves and they are scratched up a bit on the top of them right where they would be exiting the cylinder casting when they are all the way in. Would weak springs cause this? The engine is 100% fresh, but it was doing this with the old cylinders as well. I can't see any rough edges or any damage whatsoever except for the slight gouges on the top of the valves. Anybody help me out here?? I'm stumped. What would be a good exhaust spring for this sled, 700 ves rmk, 347 cylinders, bone stock, rides 3000' to 6000' Also are there supposed to be steel bushings in the plastic caps over the valves? his are all plastic. Thanks for any help. Jay

I checked some part #'s the '02 and '03 700 guillotine valve is # 5132669 (replaces # 1202091) and the '04 and '05 valve is # 5133743 Does anyone know what the difference is between the two valves? Is there an actual physical difference? I don't believe polaris ever made a S/S valve for the 700's they were always aluminum weren't they? I see that the plastic caps upgraded to a steel bushing version # 1202640 replaces the older # 5434599 but I'm not sure when they did that. How can you torque the older plastic ones? just snug them up? and does anyone have the torque #'s for the newer steel insert caps? Thanks again. Jay