Blubreadtruck

Ok, i think i may have found what it could be....It must hav enothing to do with that plug, it seems it could be something with the shift star!

here is my problem, there is a plug that is right below the front drive sprocket. It fell out while the bike was idling, all the oil leaked out. Now, when i go to shift gears, the shifter is loose, it still shifts. but there is alot of play in it. It seems the problem is the bang return spring that is in there may somehow be off, or the pin isnt holding it!!, anyone had this problem, and how can it be fixed? Thanks!