Plastic Fuel lines

[KNS]

I have the plastic CIS fuel lines on my car. On the six lines for the injectors, the thicker material surrounding the plastic line is already starting to crack and split (lines are only a couple years old - pisses me off). I know this is common but short of replacing with metal lines, can anything be done to remedy this?
Thanks..

[oneblueyedog]

I've run mine for 6 years without the sheath. I have my FI lines routed and tied with cushioned clamps away from all chafing though. Nothing touches them except for the clamps.

They are nylon. I did not use any knives to cut the sheathing off. It easily split off the nylon.

[KNS]

Thanks guys. The fuel lines themselves are fine, I'm just surprised this has happened so quickly. I was considering shrink tubing.