Welcome to all the fun. I am new here too, and taken full advantage of the knowledge here. Check them Splines, I did mine a couple days ago and was a little disappointed in what I found. Not all was lost though, not by far. I would say now that I know whats down there and I know the bike will be taken care of personally, I would say I still have many years with this one left before I have to replace the splines and shaft. Anyway, have fun and be safe.
1986 Vulcan 750
30,000 miles and counting
Castrol GTX 10w-40
WIX- Gold oil filter Pt.#1356 @ Napa Auto supply $8.00
Seafoam-2 oz. to every other tank of gas @ Napa-$10
Yuasa M/F battery- YTX14AHL-BS
Lubed Splines- Moly EP Grease, 1lb. tub $3.49-Autozone Pt.#561753
Sprayed U-joint with Liquid Wrench White Lithium Grease- $3.99 Autozone Pt.# 828796
Castrol Hypoy C 80w90 Gear Oil $5.99- Autozone Pt.#991558
NGK Iridium IX Spark Plugs, $8.99(x4)=$35.96 Autozone Pt.#088394.