dbarb3 Posted February 17 Report Share Posted February 17 Well new problem today Charging light comes on and tach stops working. Typically on a car would point to alternator. With higher rpm it dims. Where to start? Quote Link to comment Share on other sites More sharing options...
docc Posted February 17 Report Share Posted February 17 Relay #2. 1 Quote Link to comment Share on other sites More sharing options...
docc Posted February 17 Report Share Posted February 17 Source a full set of "Best Relays", either OMORON G8HE or (more available): CIT 2 Quote Link to comment Share on other sites More sharing options...
docc Posted February 17 Report Share Posted February 17 This may still lead to a regulator, or even a stator fault, but the tachometer dropping out with charging failure is classic Relay#2 (plus Relay#1 on the early Sports). Quote Link to comment Share on other sites More sharing options...
dbarb3 Posted February 18 Author Report Share Posted February 18 Will give it a try but I have the new relays in I got from DP Guzzi 1 Quote Link to comment Share on other sites More sharing options...
Lucky Phil Posted February 18 Report Share Posted February 18 2 minutes ago, dbarb3 said: Will give it a try but I have the new relays in I got from DP Guzzi Check the relay holder, connectors and the wiring behind it. Ciao 2 Quote Link to comment Share on other sites More sharing options...
dbarb3 Posted February 18 Author Report Share Posted February 18 will do is the regulator under the front of the tank Quote Link to comment Share on other sites More sharing options...
Lucky Phil Posted February 18 Report Share Posted February 18 1 minute ago, dbarb3 said: will do is the regulator under the front of the tank On the front subframe. Ciao Quote Link to comment Share on other sites More sharing options...
Kiwi_Roy Posted February 18 Report Share Posted February 18 If the Tach stops working check to see if the headlight's off as well, the regulator gets its reference from the headlight feed after the headlight relay. If the reference is missing the regulator never turns on. 2 1 Quote Link to comment Share on other sites More sharing options...
dbarb3 Posted February 18 Author Report Share Posted February 18 From reading other threads I test the yellow wires from alternator to regulator if other items check out?? Is meter set to DC and what reading should I look for? Quote Link to comment Share on other sites More sharing options...
docc Posted February 18 Report Share Posted February 18 The yellow stator wires are AC, IIRC. Pretty common that one of them detached at the stator (which can surprisingly hard to see on the bike with the alternator cover off). Quote Link to comment Share on other sites More sharing options...
dbarb3 Posted February 18 Author Report Share Posted February 18 here is the little bit know I know Changed out relay 2 no change Tach not working, headlight on Charging light not lit Battery engine off 12.15 Engine running 11.5 Obviously not charging, check wiring at alternator next?? Quote Link to comment Share on other sites More sharing options...
docc Posted February 18 Report Share Posted February 18 Simple enough to check the voltage on the yellow stator wires. The Workshop Manual says the AC voltage between the two yellow wires should be 15vAC at 1000 rpm, 40vAC at 3000, and 80vAC at 6000rpm. 1 1 Quote Link to comment Share on other sites More sharing options...
Weegie Posted February 18 Report Share Posted February 18 Pretty sure my Sporti has a similar system Before checking the Alternator I'd make sure all the Reg/Rec wires are connected............At least on the Sport there are 2 which connect with a half assed jack plug arrangment that (too) easily pulls apart I'd also check the earth on the Reg/Rec and the condtion of the yellow cables from the Alternator too You've replaced Relay #1&2 although it should be obvious but I'd check all the fuses, looks like some of them could perhaps cause issues That's if I've got the correct wiring diagram As @docc states, easy to check Alternator voltage remember AC Volts 1 Quote Link to comment Share on other sites More sharing options...
Kiwi_Roy Posted February 19 Report Share Posted February 19 20 hours ago, dbarb3 said: Tach not working, headlight on Charging light not lit Battery engine off 12.15 Engine running 11.5 Obviously not charging, check wiring at alternator next?? If you don't have a Voltage reference to the regulator the regulator cannot turn the charging light ON and neither can it turn on the SCRs to charge the battery, Check the black wire of the black / white pair, should be 12 Volts with the ignition ON The Black wire plugs into the female of the M/FM pair, its Red/Black on the loom side, connects to the headlight circuit downstream of the headlight relay, its actually soldered to the headlight feed under the tank. The Male pin on the loom side goes to the charge light, the light will turn on if you ground that pin. The light gets +12 Volts from the same wire that powers up the Tachometer. There are quite a few variations on the wiring but this is always the case, if you are looking at the M/FM connector on the loom side the Female should show the battery Voltage when the key is On (without this the regulator cannot work) the Male should also show the battery Voltage but if you touch it to chassis the charge light will turn On. Make sure the regulator case is well grounded to the engine, don't rely on the black wire that goes all the way back to the battery, its just a token ground. 1 2 Quote Link to comment Share on other sites More sharing options...
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