I am running an 86 FX 22amp alternator and it has decided to intermittently charge. 15v at the battery for a few seconds and then 4.5v at the battery and a misfire sets in, i have changed the reg/rec for one taken from a running bike to see if it makes a difference. I am running a Primo 3 inch open belt primary. I have done some of the tests laid out in the tech help and all seems right. can anyone help??