Bike Forums - Miyata ID... again

Hi everyone. I have a miyata bike with no lables on the frame aside from the shops sticker. It's all black with just the head badge and lugs outlined in gold. It has a tange headset, shimano 600 arabesque group and ttt stem and bars (maybe an upgrade?). the serial looks like it reads 1767634 or 1761634. There are also two stickers on the underside of the bottom bracket with a capital E. There used to be a tubing sticker, but it fell off. If I remember correctly it was Tange Champion #2, but I'm not sure. Any model info or dates would be greatly apprciated. I bought it for $120 with upgraded wheels (Mavic MA40/ shimano ?, Fir/ shimano 105 front), 105 pedals, and a Bontrager saddle. Is that a good deal?