Back in the day, the San Jose, CA company CC Products made some nice plastic fuel injector covers for K75s and K100s.

They're no longer available but it's pretty easy to make you own out of 1/16" (0.625) thick aluminum sheet. Since aluminum and its alloys tend to be fairly brittle, it's important to anneal it prior to bending it.  You want to bend it at a right angle to the grain of the aluminum.  If you mark the line on it where  you want to bend it with a Sharpie pen and then heat that line with a torch  (butane/propane/acetylene) until the line disappears then that's enough to make the aluminum bendable.

Here's an example of one that I fabricated and then had powder coated for a K75.

© 2013 Drake Smith - Please do not use or reproduce this elsewhere.  Feel free to link to it though.