Hi guys
new to the cbr scene and managed to score a 1993 cbr 1000f for free but the charging system is bad. I pulled the alternator and it looks brand new inside and I'm not sure how to test it. I replaced the rectifier in hopes that was the problem, sadly it is not. I checked all the connections and wires and they are all good, which leads me to believe it's the alternator. I'm hoping that isn't the case and I have been some digging and found that there could be something wrong with the chain on the alternator that could be causing it to not charge. Is this possible? If I charge the battery it fires right up and runs fine but after about 10 minutes the battery is dead and if I shut it off it turns over once then clicks like the battery is dead. Which it is. So I guess the whole point of this post is to see what you guys think before I drop 500 plus on a new alternator. Thanks in advance for any help or tips.

 

Start on page 14-3

http://www.cbr1000f.org/data/downloads/honda_cbr1000f_93_service_manual.pdf

resistance spec from my memory should be 1 ohm or less on the legs of the stator (yellow wires) and 4 or less for the field coil, I think around 2.6 is ideal (black and white wires)

 

About your Charing. You need to test if it is your battery, your Regulator or your stator. It is easy. Sorry about my english, but I am in Denmark, Europe.
First: Charge your battery totally. Then measure. Must have over 12 VDC.
Then start your engine. Measure on the battery. More than 12,5 VDC. Then go to 5000 RPM. You must now measure 13,5 to 14,5 VDC. If more or less, disconnect the connection from Regulator to Stator. Measure on the yellow wires in the connector. Here you should measure VAC. I think it should be around 25 VAC. Increase RPM to 5000. Now you should measure around 60 VAC. If you only measure below 15 VAC your stator is done. If you measure in the correct area, the regulator is dead. The 25 and 60 VAC is from CBR1100XX but I suppose its the same area for CBR1000.
Best of regards
Morten

PS: The Stator makes VAC .. it goes to the regulator, that makes it to VDC and makes the voltage to be around 13 to 14,5 VDC.

 

Great, simple answer. That's all there is to it. The stator (alternator/generator, whatever you want to call it) spins coils past a magnet and creates AC voltage. It feeds that to the voltage regulator which converts it to DC voltage which charges the battery.

So the first simple test is with the bike off, key off....check your battery voltage. Should be around 13vdc. Turn the bike on, it will likely drop below 12vdc. Start the bike and at idle it should go back up close to 13vdc, and as you rev the engine (each bike is a little different) but by 4k you should see the voltage being supplied to the battery go over 14vdc.

If it doesn't, you check the AC voltage coming from the stator. If that's good, then you're looking at a bad regulator, which is pretty common.