I have a 1988 sportster 883, supposedly bored to 1200, stock ignition system. So my problems started about 2 weeks ago. My bike was running fine, although it would backfire at the carb/misfire occasionally, this problem would go away after everything got warmed up though. I also have a weak stator, just replaced the regulator and its charging at 13-13.2v at high rpms.

One day my bike refused to start, after trying 5-6 times it finally started. Also, i think its important to mention it was backfiring out of one exhaust while struggling to start...also when i turn the ignition button off...it would backfire at the carb sometimes too. I've read in the manual that this could be a sign of bad timing? Anyways, I took the plug out, cranked the engine and the spark looked very weak. continued to ride it like that for a few days until one day it just completely died while i was riding and never started up again...no spark.

I replaced the ignition coil, but still no spark. its getting power at the coil, 10.6 volts. goes down to 8.88 when im cranking it...do these numbers sound correct? the battery is reading about 12.5 and goes down to 10.5 when cranking.

I guess my next step would be to look at the ignition sensor and rotor...i found another thread where that was the problem. Any tips in removing the sensor plate from someone whos done it before? the manual says i have to drill the rivets?

Thank you in advance for all the help, just trynna get back on my harley before the summer is over...i swear its always one thing after another.

 

None of the voltages you mention are up to spec. You have a charging system problem, by the sound of it. Low voltages will give all manner of running and starting problems. There are two Stickies in the Tech Electrical section that will guide you through the necessary checks, including testing your battery. Once your charging system is working properly and your battery is fully charged your problems may go away, if not let us know what you find.

 

hhmm what are the voltage specs for the ignition coil, can anyone tell me?

 

Check both ends of the ground strap that runs from the battery into the void behind your rear head to the frame.

if it is loose it will give all the symptoms you describe. Also check that it isnt falling apart under the insulation near the connectors.

 

drilling out the rivets on the ignition cover is easy enough, they are aluminum and you can almost just take a around 3/8 drill bit and turn it with you hand until the head comes off and then remove the cover and twist the rest of the rivet out with a pair of vise grips, there is another cover underneath that needs to come off too, if I remember right it is held on with screws.....BUT, I think your issue is with your stator or regulator...I would go back and recheck those items as the low voltage reading and weak spark aim towards them.....if your controller is acting up you normally have issues with the bike stalling/cutting off when hot or flat out not running/no spark.......you said you have a weak (yellow??) spark, the coil needs 12 volts to produce a good blue spark ....I would check the connection of all the wires to the coil paying special attention to the crimp on ends for corrosion..

 

They won't help you until you have a fully charged battery and working charging system. Check those first!

 

You do have a charging problem or a battery that's taking a dump. There should be 12v to everything g.

 

Should I have the key in the on position to check for 12v to all?

 

How long was it "running fine?"
If a good long time, I'd start with the battery.
Dropping to 10.6 volts seems extreme on cranking.
There's a test for checking stator output, but I'm only familiar with the old Hondas I used to have. Look in the manual for checking output from your stator.

It's probably going to be in the 25-30 volt range maybe. Someone else probably knows off the top of their head.

Not sure what the output is supposed to be, but check that first, with a fully charged, good battery.