Total Motorcycle Community Forums

I have had my bike on a battery tender while making the odd repair. Finally got out to ride today and she struggles to get started. I stopped at a neighbor's house for maybe 20 minutes and when I left it was harder to start than when I first disconnected the tender. I would hate to have to get a new battery, this one has maybe 2 miles on it but months on the tender. Once she gets started the ride is fine but I don't want to go far from home in case she decides not to start the next time I stop somewhere. I have no mechanic experience so this will sound odd, do motorcycle batteries charge while the engine runs?

As per your other post, my first recommendation is to get a service/repair manual. I'm assuming by "struggles to get started" you mean that the motor turns over very slow and not that it fires up right away but takes a while to warm up and not keep stalling.

That being said, yes, motorcycle engines do have a system that charges the battery as you ride. If the bike is hard to start after shutting it off after a long ride, the charging system may be at fault. Usually this can be traced to a bad voltage regulator/rectifier, which is a small black box normally placed somewhere low in front or behind the motor. To check it you need a "multimeter" or "voltage meter", which is an electronic tool you can purchase at any auto parts store or electrical supply store. The instruction manual will detail how to set it up to measure voltage, once that is done you place the red lead on the positive side of the battery and the black lead on the negative side and check the readout. With the ignition OFF it should read 12V. Then you start the bike and hold the throttle above 1000 RPM and check the voltage again. this time it should be 13V-14V, indicating that the system is working. If it stays at 12V or starts slowly dropping, there is a problem with the charging system. At this point you can either try replacing the regulator/rectifier yourself, or take it to a bike shop for repair. Sometimes, rarely, the problem is not the battery or regulator/rectifier but the actual alternator itself. That can get pricey as it requires digging into the motor to replace it.

I have searched for service and repair manuals for this bike but Clymer and Haynes haven't done a manual yet (and have no intention to any time soon per their email response to my question), and the service manual just seems lacking in comparison. It does have electrical systems info and a diagram. I'll be starting work on that this weekend. I appreciate the response and tips.

Corvy

Gummiente has the right idea, definitely sounds like the charging circuit. try doing the same as I did when I had a similar problem with my Yamaha, check the battery terminals, somehow mine got loose. (Or I was a dummy and didn't tighten them properly when I installed a new battery. )

I've run the multimeter on the battery while the bike was off, while disconnected from the bike, and while the bike is revved. I even brought it to a shop to get it checked just in case I was reading it wrong. The battery is fine. The battery connections are clean and snug. I've used the multimeter to check every connection in the service manual and nothing came up an issue. I had installed a horn previously but didn't have to add any wiring as that was already waiting for the horn to be hooked up. The only thing I can think of is the previous owner installed a tachometer and the wiring involved. Could wiring that wrong allow it to function but still drain the battery while the bike is off?

Corvy

The short answer is yes. HOWEVER, you need a manual to follow a wiring diagram and
test for where yo u loose th e voltage.

There are several listed with a google search or you could look at google images. I find them difficult to work with myself.

I finally had a chance to work on the bike with my husband assisting (he has electrical experience but not motorcycle specific). We removed the tachometer to see if that was the issue. He was very unhappy with the way the wiring was done so it may have been faulty there. Turned power on to test and ran the lights. The front blinkers alternated flashing regardless of which one was switched on. We disconnected those to see what change would be made... all the other lights were much brighter and the rear blinkers flashed faster... so we're thinking the problem is a wiring issue at the front lights, perhaps caused by the shoddy wiring of the tachometer? If I can get the bike running without the front lights then I'll take it into a shop to get someone to check it out.