This problem has haunted me since I bought this bike 2 years ago. While riding the bike it will ride perfect till the fan turns on. When the fan turns on the bike begins to stutter at idle bouncing around 1500rpm-1000rpm eventually it will die. It lets me start the bike back up but recently it has not wanted to start immediately meaning it would turn over to slow to start up. Instead I would have to wait maybe 2 minutes than it will turn over no problem. In the past I’ve replaced the stator, regulator with a gsxr600 and a computer fan, battery from amazon, and the fan with a lightweight one from amazon. The only one that made it ride normal was when I changed the fan. But a month later it went back to stuttering. I checked the battery bolts and when sitting it’s at around 12.7 but when I start it up it slowly goes to around 13.5 to 13.7. When the fan kicks on it drops to 13.3ish. But after riding for 5 minutes it will begin to stutter and will drop to somewhere around 12.3-12.7. I also checked the stators ohms and all of them said 1.7 but the owners manual says that it should be between 0.1-1.0 ohms.Update: I came from a ride today and the bike again died at a stop light and struggled to turn over till I waited like 15 seconds (the fan was on). I raised the rpm to 2000 and it was chill for the rest of the ride. But when I got home I checked the voltage of the battery with the key off and it was 13.3 with the key on it was at 12.7 but when I tried to start the bike it dropped to like 8 or so and wouldn’t turn over. The bike was hot when I did this and the fan was on.

I also checked the r/r for its voltages or what ever and it looked fine all the yellow wires were at like 540.

 

This would make you strongly suspect a faulty fan switch, but you really should test the stator output in VDC, as this will not help, be aware that bike charging systems are marginal at best, and any weakness will lead to failure.

Dink.1170

 

How's the battery? If it dropped to 8V immediately after reading 12-13V, that points me to a dead battery (no capacity)

It's possible to charge a dead battery, so it may look good if you take a voltage after boosting it, but if it loses charge immediately that's a strong sign that it's due for replacement. Even if it's relatively new. It's a good idea to use a booster pack for troubleshooting so that you don't go buy a new battery only to drain it as well (I've done that several times)

As Dink.1170 says, you will want to check out the fan switch, and I'd give the wires a quick look to make sure a bare wire isn't grounding to frame or something like that. Keep an eye out for melted or wrinkled wire insulation and any mods on the circuit are also suspect. Aftermarket LED's are a common culprit, but from what you describe it sounds like the fault is most likely on the fan circuit

If the stator resistance is abnormally high, that's another item you could investigate. Components can read higher resistance if they're in poor contact or dirty, but the difference between 1 and 1.7 ohms isn't high enough that I'd suspect outright failure. As I say, that might be something to check out, especially if you had to splice wires to fit the gixxer parts. It's also possible that a splice may have gone bad. If nothing obvious jumps out, it might be worthwhile to focus on the fan circuit, and probe the following connections:

-probe for continuity on any wires that have been spliced (checking for broken wires/splices)
-probe for no continuity on positive wires to ground (checking for ground faults)
-probe for continuity on negative wires to ground (checking for broken/damaged common grounds)

For bonus points you can bench-test the fan using a 12V power supply

Hope that helps

 

I have had a similar issue with my bike, and I thought the stator was fine. Voltage increased on the battery side too, to 13.5V
​​​All was fine until I measured the AC side of the stator. Then I measured between the phases, 13VAC, 9VAC, and 8VAC.
Stator was blown.
This was due to the stator that got too hot in a slow ride and when the fan turned on it must have been the end of the stator.
What I notice is that your fan goes on quite often. It rarely happens on my bike. You might want to investigate why your fan turn on so fast and often