Not cleaning, fixing. You know the cover plate on top of the little bugger, held down by two phillips screws? Take that off. You'll find a little screw-in thingie with a notch on each side. Screw that in tight, it tends to loosen up after 17+ years. That will usually fix the problem.

If I can find a picture, I'll show you. It's been a while since I sold my '87 Si.