Re: 88 150 Voltage Reg.
Your regulator can be replaced with any of the newer 5 or 6 wire recifier/regulators if you feel there might be an issue. The 5 wire are 2 yellow, 2 red and 1 gray or 2 yellow, 2 red and 1 black, (use a yellow for the tach instead of gray). The 6 wire are 2 yellow, 2 red, 1 gray, 1 black but are often referred to 5 wire also.
I prefer the later 6 aka 5 wire. The black is a ground and I like having a ground I can position optimally. The two red wires have a different purposes, the smaller one gets feedback from the battery and is called the voltage sensing lead. The other is the DC charging lead. They are both tied together at the main battery positive lead, (usually). The smaller sensing lead gives the regulator feedback from the battery and tells charging side how much juice the battery needs. This helps to prevent overcharging, which is the oxymoron that J_Martin and Silvertip are both elluding to when talking about not needing a regulator.
The two yellow wires accept A/C input from the two yellow wires comming from the stator. The gray wire is for your tach and is protected from voltage spikes that cause errratic tach movement. You can also tap into eithier (not both) of the yellow wires for the tach but depending upon the condition of your flywheel magnets, grounds, stator, etc, you could see some erratic movement, (that's not all that common but it happens).
If it was me, I'd run one but it would be a newer 6 wire. My 02 Cents.
