Common Technical Issues : GS850G (82-83)
BRAND : SUZUKI
MODEL : GS850G (82-83)
CATEGORY : Street Bikes
TECHNICAL ISSUE DETAILS
Suzuki's GS850 models all use a permanent magnet alternator system for charging the battery. This system consists of a stator with three output leads and a separate regulator/rectifier.
Problem however is that the way Suzuki handled the regulation on these bikes is not very good. To save expense in the regulation circuits Suzuki decided not to regulate all three phase inputs (all three wires coming from the stator), but only ONE. One of the three wires from the stator (YELLOW) feeds directly into the rectifier circuit without ANY regulation. One of the three stator wires (WHITE/BLUE) feeds into the rectifier AND has a regulation circuit attached to it. The third stator wire (WHITE/GREEN) feeds into into the bike wiring harness, connects inside the headlight to the handlebar switch and comes back from the handlebar switch as a WHITE/RED wire which connects directly into the rectifier bridge without ANY regulation.
NOTE: the stator output is identical on all three wires. The three different colors are not needed, it does not matter how you hook up the stator wires as long as you hook them all up. The result of this cost cutting is an unbalanced load on the stator (the stator wants to see an equal load on all three phase outputs) which causes premature stator failure.
Our replacement regulator/rectifier regulates on ALL THREE PHASE INPUTS. This means that the load on the three phase outputs of the stator is equal, greatly improving the system and its reliability. Our ESR models for these Suzukis therefore have THREE YELLOW INPUTS. And it does not matter which YELLOW wire connects to which stator output wire.
We recommend removing the loop through the wiring harness and connect the WHITE/GREEN stator wire directly into the regulator/rectifier. If you replace the OEM stator with one of our ESG stators you will notice also that the output leads of this new stator are all YELLOW.
We also recommend checking all electrical connections in these bikes. The connectors are not that great, and the bikes are fairly old by now. Clean the connectors one by one with some contact cleaner and make sure the bullet style connectors are tight.
Our Fault Finding Guide will be a great help in diagnosing when you have a charging problem on these Suzukis.
To test the diodes in the rectifier part of the regulator/rectifier you can use our Diode Testing Guide.
NOTE: EARLIER (1979) 8-valve GS850 models have a 12-pole three phase stator (=ElectroSport part number ESG015) that has identical dimensions to the later 18-pole units (=ElectroSport part number ESG011). You can use an ESG011 in these older 8-valve models, but you will have to use the later model (80-83) GS850 flywheel. If you fail to change the flywheel the number of magnet poles does not match the stator and you will have NO OUTPUT from your new 18-pole stator.
We recommend simply installing the correct ESG015 12-pole stator in the 1979 GS850. Later GS850 models (80-85) use the ESG011 stator.