I also found the tube to be damaged on my '86.  It was crushed and torn
near where it attaches to the tube on the air cleaner side.  I currently am
running without it in place.  It is a little louder now.  Surprisingly, I
have noticed no power improvement.  I am guessing that the constriction
would have been more evident at higher rpms, where I rarely go.
Edward

At 08:55 AM 9/17/2004, you wrote:
>I had exactly the problem you describe with my conversion.  On the second
>day of a 3000K maiden voyage I suddenly lost power and could only manage
>35mph uphill, and 60, after a long acceleration period on the flats.  The
>problem was the tube itself collapsing under the extra vacuum of the I4
>engine.  I was rather mystified for a fix until I pulled the air filter and
>saw all the foil and carboard that had been sucked in.
>
>I replaced the tube with a generic air intake tube purchased at a Canadian
>Tire store for about $10.  You'll need to pull the engine vent grille and
>remove the "snorkel" so you can clamp on the new tube.