Wiring Have a 1978 850T3 took off fairing found bad connections replaced god wiring done front part of bike turn siginals , lights etc , problem is wahat wires goes where starter, regulator, altenator, rectifer, yes have a manual on bike , have gone over and over still havent had any luck would like to have bike running spring time closest dealer is like 300 miles away
Motorcycles - Moto Guzzi - 850 T 3 - 1978 Moto Guzzi 850 T 3
Answers & Comments
Lets start with the battery. There should be a relay of some kind with two large wires hooked to it, and maybe 5 other smaller wires. Now the one large wire should go to the relay direct from the battery, then the other large wire will go to the starter. When the connection is made between these two large wires the starter should turn. Now there will be one or two smaller wires that control the relay, ( these are hooked to a post or posts on that same start relay), so it will pull in and make the connection between the two large wires to turn the starter. You can check this with an old school 12v test light, hook a hot wire to one side of the start button from a hot wire here in the relay, (one that is hot when the clutch is pulled in or the bike is in neutral -- clear as mud?) or it can be hot all the time, but the starter will turn every time it's touched. Some old school bikes are wired like that anyway. Go and push the starter button and check wires until you find one that gets hot only when you push the start button. Then back to the relay, pull that hot wire from the start button to the relay and touch it to the small post and see if it will now energize the relay when the start button is pushed. Now once all this wiring is fixed it should turn over the engine, when the start button is pushed and it's in neutral or the clutch is pulled in or it will take off on it's on. Next the Alternator, one of the medium sized wires should come straight from the battery to the regulator nothing in between, thats is the regulator exciter wire, next is the, alternator wires, there should be 2 or maybe 4 wires coming out, and if there are 4 they are in pairs these are the A/C output of the alt. These wires will hook to the rectifier, You should have one wire going to ground from the rectifier, then, these 2 wires from the alt. then a wire that hooks to the regulator as 12v hot out of the rectifier. See this is how the Alternator works is produces A/C voltage (say 28, 30 volts A/c) then the rectifier converts it to 12 volts + - D/c the - negative is the ground wire. The regulator will Check the volts at the battery and adjust the output of the 12vdc from the rectifier and let it pass on to the battery to charge it. I hope some of this helps you, I hope it makes sense. I would love a bike like this. . . .