1977 Suzuki GS750 Charging System Upgrade

| 8/8/2018 1:32:00 PM

suzuki charging system upgrade

Charging systems improved markedly in the 1970s, both in terms of output and component quality. But age isn't always kind, and 40 years later, many of those systems are experiencing their share of issues. Burnt or corroded contacts in the charging system wiring are something of a silent killer, creating resistance that heats up the wiring, often leading to stator failure.

That was the case with our subject 1977 Suzuki GS750, which was suffering from low voltage output from the stator to the rectifier/regulator. One of the stator's three output lines was badly burnt at its connector. The rectifier and voltage regulator were working properly, but there wasn't enough voltage output to keep the battery properly charged. The problem most likely started with mild corrosion, then as resistance built and the wires heated up the connection started burning, to the point where voltage output from that phase of the stator was blocked, leading to more problems with the stator itself.

suzuki charging system upgrade

At the same time we were looking into the Suzuki's charging problems, we learned that Rick's Motorsport Electrics was introducing a new line of lithium-ion friendly rectifier/regulators to pair with lithium-ion batteries in vintage bikes. Incredibly light and with no corrosive acid — you can mount them upside down if you want — lithium-ion batteries make great sense, but their use in vintage bikes has been somewhat limited due to the high charging voltage output on many older machines.

In a 12-volt application, a typical lead-acid battery works well with charge rates up to around 14.5 volts, but lithium-ion batteries work best with a lower voltage charge and within a narrower range as they don't like large swings in voltage, something lead-acid batteries tolerate well. Working with lithium-ion battery specialists Ballistic Performance Components, Rick's has developed a line of rectifier/regulators specifically tailored to the voltage output required for lithium-ion batteries.