OP is lacking in Forum skills. WHAT.......YEAR......IS......YOUR.....BIKE.....AND ......WHAT......MODEL.....IS.....IT? That would help a lot in trying to give you a definitive answer to the problem.

 

Keep saying "battery is fully charged" but-did you have it load tested?

 

I've even had batteries test "good" on a load test and STILL not start the bike reliably. Put in a new battery and BAM! Instant start.


IMO, the "load tests" performed at your local auto parts store are next to worthless.

 

So, got a lesson in batteries. Earlier this year I was in a bind and bought a battery from Advance Auto. Assured it was the worlds best battery. Now less than 8 months later, won't hold a charge. Now they tell me their batteries are only good for 90 days, and they are not designed for daily use. I ride every day, rain, sun, cold, just not in ice. The clerk even said "you know how to keep these working don't you?" Meaning a tender. They then tried charging me $140.00 for a new battery.

Lesson learned: never buy a battery from Advance Auto. Went to the local battery supply house and got a new battery. These guys also ride and this is the battery they all use. Now my starting issues seems to be in the past.

Thank you to all who commented and helped me through this. By the way, I put on new battery cables also. Why take a chance.

 

Kinda funny this topic popped up. I have a '06 Deluxe. I put in a new standard Yuasa battery in about a year and a half ago. But over the past couple of weeks, starting has been sluggish enough to get my attention. It'll crank over about a half turn, almost stop, then crank over. The motor is stock, so it's not like a high compression deal.

This morning, I thought I'd ride her in to work. It's been getting colder in the mornings here in Central California (High 40s), but not really cold like one would see in the midwest or in the east. I hop on and she cranks over, a bit slower than normal, and wouldn't fire, even though I rode her yesterday evening. It did this before too right before I put a new battery in it. My Sportster would crank but not fire if the battery was weak too.

I didn't have time this morning to dink with it, but I'll bet a good chunk of cash money, that if I put it on a charge this evening, she'll fire right up.

So what is the general consensus on which battery and cables are the best choices?

 

If you're sure your charging system is working properly (check with a voltmeter), the easiest way to check if your battery has proper starting load capacity is to jump it with another battery, and see if the bike starts much easier.
Do this without the engine running on the car you jump from. You want to see how your bike starts with 12.5 volts, not the 14+ you'll get if the other engine is running.