So there I was Sunday morning in the freezing cold, getting ready for my first hare scrable. Every thing was going great, bike was running well. I moved to the start line, killed the motor, restarted to make sure there was no issues, and everthing worked as planed. I killed it again because it was a dead start, and i was anxiously waiting the starting horn. The horn blows and I'm ready to go, but wait... it wont start. I panic trying to figure out what i did wrong. All the other bikes around me I can't hear what mine is doing. I push it off the line so I wont get run over by the following waves and that is when I realize that the battery is dead. How can that be? I had it on the trickle charger overnight, which said full charge and I only had the key on without the motor running for about 1 minute max.
I was able to push start it to get going in dead last. I catch up and pass a few riders quick, and about a mile into the woods, a few bike pile up infront of me. in my inexperiace, I droped the clutch and kill it. Son of a gun it wont start again. I get lucky and there was a road right around the corner that I was able to push start it again. All I can think about is not killing it again. I managed to complete the first lap without anymore issues, except for riding like crap because I was paranoid I would kill it. Not wanting to risk it happening again, I called it a day. At that point I was exhausted from push-starting a few times.
Now here is the really odd thing. After that. the bike ran like it was brand new again. I can't figure out what could have drained the batery that fast. Could it have been the cold, it was about 40 degress that morning?

 

That's not an extreme temp for the KLX battery/starting system...especially when it sounds like you didn't have the cold start issue to begin with that some have. The fact that it didn't exhibit any similar problems later makes me think the day had warmed up enough not to challenge a minimal battery, perhaps. How old is your battery? Why did you have it on a trickle charger? Have you had a similar problem before when cooler weather hits.

If you have the repair manual for the bike, follow the testing procedure for charging output as outlined with a meter while running the bike. If it checks out, your battery is probably on the wane. Some shops also have battery testers that put a load on the battery that will reveal a weak battery even when a simple voltage check shows proper voltage. Checking the specific gravity of the acid/water mix in each cell is usually a good "home check" on a fully charged battery, but most KLX batteries don't allow this very easily with their sealing system.

Additionally you could have a draw somewhere in the system that bleeds the battery. You can usually check this with a meter.

 

Bet you wish you had a kickstarter. I've been on a starting line like that and when all the other bikes roar to life and go to wide open throttle at one time it can be a very loud and lonely feeling to be setting there with a dead bike.

 

i'd check for a loose or corroded connection

 

Do you have a volt meter?

Static voltage should be 12.6
Cranking voltage should not go below 9.6
Charging should be close to 14 volts.

No load tester needed, use the starter.

You probably do need a battery, but do these checks first to know were you are at.

David

 

All the times i've laughed at the guys trying to kick start their bike while i just push a button and take off. I guess it was pay back time the sweep riders prety looked at me like i was an idiot for not having a kick start.
I'll get a volt meter to check it out.
I just put it on a tricke charger as a precaution. There really wasn't a need for it. I rotate all my bikes on the trickle charger.

 

If the battery is buggered and at the end of life, a trickle charge won't bring it back. Most "bad" batteries are caused by sulfation between the plates not allowing the current to flow as easy. Trickle chargers adjust the output voltage to the battery based upon this current flow.

I just replaced my battery a few weeks ago in the KLX, put the bad battery on the trickle charger and the charger thought it was full, even tho it would barely light the headlamp on the bike when asked.

A simple voltage check during static conditions, headlamp operation and start should tell you if your battery is good or not. If your battery checks out to be good, I would trace your wiring out to be sure you don't have a loose or corroded connection.

 

Did you remove the headlight before the race? Just wondering, if you had your key on getting ready for the start, how long was the headlight burning before you got the "go" signal? Maybe the combination of an already weak battery, plus burning the 60W headlight for 20-30 seconds or more was enough to drain it low enough that it wouldn't crank?