I didn't have a larger front sprocket commonly available myself, so I looked around for the smallest rear sprocket that would fit my hub/chain size. I found
JT Sprockets: Motorcycle & ATV Sprockets to be invaluable and cross referenced the materials there to something that would fit off a completely different bike.
Your 17 tooth front sprocket is already the largest commonly available (as was mine) but you could go down to 38 teeth (from 42) on the rear. Just shop/ebay around for a 1997-2000 Suzuki TL1000 S V/W/X/Y rear sprocket, or by number it is a 499.38