10 seconds is a long time to crank a starter, if you are actually cranking it this long....... the starters windings and brushes might be getting wore out, if thats the case a new battery might not help much or at least not for long. Our poor little starters get a hard workout.

sorry just one more link in the chain.

 

make sure your ground is good and solid as well.

 

Like water in a pipe you need a clear pathway with low resistance. Battery voltage is a good start as is checking your grounds. A load tester maybe what you need but will probably lead to a new battery.

 

You may have measured 12.9V after running the bike. Measure it 4 hours later. A fully charged battery will be 12.7V.

The only other way to check a battery is under load. It should support half the CCA rating for 15 second and not drop below 9.5V. You should also be able to crank the starter for 15 seconds and not drop below 9.5V either. After 10 minutes the voltage should bounce back to 12.5V on a good battery.

You can check your charging system while the bike is running. Just measure the DC across the battery. You should see 13.8-14.8V on a healthy system which will charge your battery.

 

@ wedge, you're right I probably wasn't cranking for 10 seconds at a time. Looking at a second hand on a clock, I bet I was cranking for 5 seconds max.
@wildcard / drm I will be cleaning and checking my ground. One of the guys at the club questioned the same thing.
Just checked again tonight 12.82v on a Fluke meter. Battery has been out of the bike for two days now. I still need to check the voltage the bike is putting out when running.
Thanks for the input you guys.
Dan