[TRK]

Giving the engine a close look I have noticed a few wires that seem to lack isolation:

Any suggestions as to what should be used over them? Have some kapton tape on hand, but it's too narrow and won't hold to these parts.

 

[jdock]

The wires are insulated. In the first picture the insulation is the red and green over the wires.
What I think your asking about is the tubing that goes over the wires.
Its there to protect the wires more and to keep them bundled together.
At the ends where they make their connection it will look like what your seeing and it will not cause problems.
If you try to tape all the way to the end, you will end up with the tape not sticking completely, and a gummed up sticky mess of wires attracting dust and other crap.
Best to just leave them as they are.

 

[TRK]

If you try to tape all the way to the end, you will end up with the tape not sticking completely, and a gummed up sticky mess of wires attracting dust and other crap.
Best to just leave them as they are.

Excellent, thank you!