Something to think about while in class

I was almost late for class this morning; the bike didn't want to start for me. It had been sitting over the weekend, it had gas, and when I woke up this morning, the battery probably wasn't fully charged but it had enough to turn the engine over plenty of times. Anyway, after trying for several minutes and wearing down the battery considerably, I decided to bump-start it. Worked like a charm, and I was off. But as I try to accelerate from a stop sign, the rpms drop, the engine bogs down, and, unless I open the throttle completely, dies.

So now I'm sitting in class trying to figure this out, and I thought I'd see if you guys had any ideas. I'm going to check the float levels and charge the battery later in the day. Anything else I should check?

 

Have you checked your charging system output? Fully charge you battery, then measure the voltage across it with the bike running. It should be over 14V at 2k rpm, and under 14.8V by 5k rpm.

 

New coils and spark plug wires has totally transformed my bike's cold starting ability.
I never questioned the coils until 1 failed on me, but now that I've changed them, the difference is huge.
Just one of many things to check...

 

How exactly do you check your charging system?

 

easiest way to check is like ManBot13 said, Use an electric tester, put the red one on the positive terminal, and the black one on the negative terminal, and the readings should be as listed here (although i wouldn't be surprised to see something like 15.5V @ around 5-6K rpm) Remember, all of this in DC current.

If the reading goes down from the bike not running, then the battery is not getting any charge, so likely the stator is bad or the regulator is bad, those tests take a bit more effort, so if you have problems at the terminals, let me know and I can try to walk you through that process!

 

Actually, the regulator, according to the Haynes manual regulates the voltage at 14.5 +/- 0.3 V. At 2k rpm, the alternator produces enough power for the regulator to put out 14.2V and enter that range. If you get more than 14.8V, your regulator isn't functioning properly to regulate the voltage.

 

Agree, it SHOULD not get more than 14.8, but on all of the bikes i've dealt with, you will see jumps to slightly over that, and many would sit a bit higher than they are supposed to. They try to regulate them to putting out no more than approx 2V over what a charged battery should be (12.7) so it would be equal to a 2 amp charger, but many times they will produce more than that for short periods of time.


Now, I may be completely wrong about this, so if I am, just tell me to shut up!

 

My guess is a combination of low voltage from cranking it so long and the engine being partially flooded from cranking it so long.

 

I agree with Gamuru...

I was jumping the gun and suggesting that you find out WHY you had low voltage to start with. Could be bad battery that can't hold a charge (you can test this by fully charging the battery, then seeing if the voltage drops after 30 minutes - it shouldn't drop at all).

OR the battery might have been fine...but your charging system wasn't working. That's why I suggested checking it (without further explanation) ...if you try to run on your battery too long, it'll end up in the case mentioned above (ask me how I know).

tjwor - over-voltage can be a serious problem - I'm not sure what voltage the components are designed to handle...but there's a reason the voltage is regulated. I would be concerned if the voltage goes over 14.8 much if at all (my regulator is still up to the task, and it's even had the red wire melt in the past).

 

Agree, it SHOULD not get more than 14.8, but on all of the bikes i've dealt with, you will see jumps to slightly over that, and many would sit a bit higher than they are supposed to. They try to regulate them to putting out no more than approx 2V over what a charged battery should be (12.7) so it would be equal to a 2 amp charger, but many times they will produce more than that for short periods of time.


Now, I may be completely wrong about this, so if I am, just tell me to shut up!