Re: 1983 yamaha varago 750 foul plug

our electrical systems are weak and so they must be in top condition before they run..meaning,,new plugs, preferably bosch 4237 or autolite AP63;;next is a battery that is two years old or less,(unless it is the gel battery which i have heard lasts up to 5 years), make sure all connections are clean,,take your sparkplugs out and ground them to the cylinder head,,,what is the condition of the spark? yellow and weak or blue and bright? if weak and yellow you may need sparkplug wires,,have them check the condition of you coils, a simple compression test will indicate the condition of your rings, it should be around 150psi, per cylinder, shouldnt be more than a few pounds off between the two,,and if its close to 100psi its due for rings,,using wd-40 spray the hoses and boots around the intakes to try and detect any vacuum leaks,,that will reveal itself by a change in rpms,,and of course the o-rings in the pilot air screws have been replaced, float level in the rear carb is where it should be,,an accurate method of checking this is to take a length of clear hose and attach it to the drain on the carb,,next hold it up above the carb while opening the drain screw on the side of the float bowl,,the fuel level should be right at or just below the seam where the float bowl meets the carb body. is the tachometer behaving? usually if the tci (the brain) is going bad it will reveal itself by faulty rpm readings,,jumping etc. it can be rebuilt...check all these things and let me know what you find in detail..take care good luck,,,yg