Hello! I am trying to figure out what is going on with my 2002 Harley Sportster 1200C. I hadn't ridden it for a month due to training somewhere away from home and when i got back the problem sudden arose. I tried to start my bike and it wouldn't start. I figured my battery wasn't charged so i tried to jump start it myself going down a hill. It still would start. So i jumped started it with my truck and battery. It started! But then it wouldn't run unless held mid-throttle and higher RPM. I let it warm up, used the choke, and held it for about 35min, but it would die when I let off. I had to drive it, due to moving, and i figured it would work itself out after the ride. Every time I came to a stop it would die and have to be re-jumped with my truck. Any ideas?

Summery:
Has to be jumped started, won't idle, dies when let off throttle at all.

Thank you all in advance!

 

You check the voltage of the battery to see if its dead?

 

Start with a fully charged battery before doing anything else. How old is the battery? Battery tender will not charge up a dead battery. New or charged battery may fix the idle problem? After that check the charging system, RPM's have to be up over 2,000 before it charges. Good luck.

 

Hope you didn't start it with the motor running on your truck.

 

I am sure my battery may be dead. I DID jump start the bike with my truck, I have done it several times in the past that way. I think they are both the same voltage so I haven't had anything happen in the past that way. @Hippie49 i understand over voltage and the damage it can cause but I assumed it would be ok with these batteries, am i wrong? @Moe55, after i did get the bike jump started, i rode it for about 30min on both the highway and regular streets. In the past, I have ridden it with a dead battery and it would still atleast idle once I came to a stop. But this one would die out at like 1500rpm and below. I tried to save it by giving it gas and it would still die. I was hoping the stators would charge ol' girl up but it didn't seem they were working. My second guess was bad stator, and third was maybe a dead spark plug making the other cylinder maybe have to take on the load of both cylinders. What do you all think? Ill try to fully charge the battery. The battery is almost 2 years old, it gets a battery tender every now again. I have been a bit abusive to the battery specifically.

 

If the truck was running when you jumped it, you most likely damaged one or more components of the charging system.


Replace the battery, the do the voltage/ohm checks on the regulator, stator, and rotor.

 

its your battery ,,

 

Ill start out with replacing the battery then. @toypuller, i have jumped it several times with a truck. It seemed to have been fine. I wonder if maybe i just finally did it one too many times.

 

Mark, I hope it didn't affect anything in your electrical system and it may be possible that it didn't.

It's just something that I wouldn't do.


Good luck and let us know what you find out.

 

FYI Harleys electrical , including ignition, are supplied by the battery. The alternator supplies the juice to the battery to power the bike. I'd replace the battery, then do a charging system diagnostic to make everything is working correctly.