I am trying to figure out the problem that is been confusing me.  I have had my carbs cleaned and was still having an issue so I pulled the wire off of the right rear plug and put in another and placed it to the block to check for a spark.  I noticed a small spark when I turn bike over than stopped until I reached 4500rpm then recieved a big spark.  repeated the same test to theleft rear and noticed no spark at all.  Would this be a wire or coil issue?  I have a 1985 Venture royale 1200 cc