I just inherited a 1975 850T that has been under a tarp for the past 25 years. there is some significant rust but I think it can be cleaned up. It only has 4700 miles on it. I can get the engine to turn by putting a jumper cable on the starter but I don´t get any spark and I can´t get it to crank by using the starter button. the points move and look clean. I don´t know where to go from there. Any ideas.