On my '03VFR the Speedometer pick-up sensor is located on the countershaft sprocket cover. Left side of the bike. I believe they were mounted in the same place on the '97s. The cover is located just forward of your left footpeg,the clutch slave cylinder bolts to the cover,the speedo sensor is the black plastic thing bolted right in the middle of the cover,can't miss it. The Speedo sensor has a little plastic coupler that is driven off the hex head of the bolt that holds your countershaft sprocket on. If the countershaft sprocket bolt has backed off,it could've damaged that coupler. Or the plastic coupler has simply stripped out from working against that steel bolt head. Unbolt the Speedo sensor(it's just two little bolts)and remove it,see if the hex shape of the coupler is rounded out,or if the hex shape of the sprocket bolt is rounded. Either of these could give you erratic readings. If the bolts that hold the countershaft sprocket cover are loose,or the bolts that secure the Speedo sensor are loose,these too could cause an erratic Speedometer reading. Remember to check the connector plug where the Speedo sensor plugs into the wire harness,plug and unplug it a few times for good measure,you might have a little corrosion there. Or you could simply have a faulty Speedo sensor. I hope this helps you. Good Luck! Remember,you're not braking til your rear wheel's lifting,until then you're just slowing down.
