Headlight Out

[D_Sp8s]

Last night I noticed that my headlight would dim and slowly go out around 9000+ rpms but would come back on when the rpms dropped back down. However, the headlight is the only light that does this. I looked at other lights during high revs but they are all fine. I have no clue what might be doing this so any help would be great. Oh, yea...this is on a '93 CBR600 F2.

EDIT: Its a few days later and now my head light will not work under any circumstances. It is still the only light that is not working properly. I visually checked all connections. I also bought a new bulb and tested it but it didn't work either. Any body have any ideas??

[jah]

it might be anything. the bike maybe great but its sort of old and 9000rpm is near red line. a service manual would help.
dont run the bike with the battery disconnected.

when this happens does the bright lights circuit also do it?

-verify the headlight and its connector are ok
-verify the wiring harness dosnt have a open or a short to the frame.
-verify the headlight fuse and its connector are ok.

since this only happens >9000 it will not by itself discharge a functional battery. are lights acceptable brightness w/o the engine running and the key in the accessory position? if not; maybe the regulator is droping out at 9000 and falling back to a partially dead battery.

if you must verify the alternator:
-you could inspect the alternator windings, usally the damaged phase(s) are all burnt up black.
-use a AC volt meter and verify the voltage across each of 3 phases, they shoul be the same. compare readings taken at the same rpm say 5000rpm. with the alternator leads disconnected you should see the voltage increase with rpm.

[D_Sp8s]

Thanks for the help. Yes, it is sort of an older bike. Redline is at 13,000rpms and rev-limiter kicks in at about 14k-ish I think... I replaced the regulator/rectifier a few months back as well as the battery. The headlight is very bright when the engine is off and the key is on. But thanks for the info. I'll check it out more this week.