Re: 1981 535 Virago Help

I have a 1987 535 virago 17000 miles with almost the same problem back fireing sometimes and when I give it gas and hold the throttle in one place it barely goes then all of a sudden it takes off like a bat out of hell.this happens off an on not constant.I had a shop tune it up cleaned the jets new plugs new battery new voltage regulator,replaced 1 new slider for the carb which is also the diaphragm,ever time they add these parts it works good for 2 days then back to the back fireing and spuddering again off and on.the shop I ve taken it too thinks it electrical but up to this point they still don t know what it is.starting to cost me alot of money.on that year of bike shouldn t be that hard to find the problem, it not like it s one of these new bikes that are all computerized.since they tuned it up and done everything they ve done it runs really good when it aint back fireing and spuddering this really sucks because it s the wheels I have to get around