It’s important that everyone knows most modern bikes don’t have alternators. Instead, they have a seperate stator coil and voltage regulator/rectifier unit (the two components found in an alternator in a car). The entire charging system of a modern bike consists of these two components and the battery. The reason this is important is because what most people don’t know is that while stators are virtually bullet proof and will never fail, the R/R unit on most bikes IS prone to failure, ESPECIALLY on bikes like the Suzuki SV650.
The R/R unit is usually found in the rear fender along with the cluster of wires that leads to your taillamp cluster and looks like a metal finned heat sink with a bunch of wires sticking out of it. These little components are especially prone to failing on bikes that log lots of highway miles because they lack the ability to disperse heat when the engine is running at high RPMs. It is not uncommon for people to have to replace their R/R unit when replacing a bad battery because riding with a bad battery is a good way to fry your R/R.
Diagnostic procedure is, once a known good fully charged battery is hooked up to the bike, measure the voltage across the battery terminals with the bike running. Then measure the voltage across the battery terminals with the throttle at 1/2 redline. On a 12v battery, voltage at both points should be a MINIMUM oof 13.5 volts. if it drops below that on a known good battery, then that means either your stator or R/R unit is toast, and since 99.99999% of the time its the R/R, you know what that means.
Like I said, R/R units are prone to going bad on all motorcycles, but ESPECIALLY bikes that log lots of highway miles.
SV650s in particular are known for going through R/R units like condoms because the stock unit is undersized. A common modification for them is to replace it with one from a GSXR or honda CBR1100XX. These beefier units usually require fabrication of a mounting plate (a piece of sheet metal will work) and thicker wire gauge, but its worth it in the end because youre ending up with one thats actually durable.
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