I have an 88 RR clasic over the last week it has been loosing more and more power, now it will just idle and when you put in in gear and step on the gas, it sputters, will hardley move. Over the last 8 months i have replaced the alternator, fuel pump ( 6 months old) and sounds good/filter( about 1 year ), plugs, wires, cap/rotor, air bypass valve and have a new throttle potentiometer on the way ( not sure if that will help) but it is old so why not. working my way through the manual, can anyone help please.