I have a 90 VFR and I recently noticed during an evening ride that my lights flicker (all of them including the instrument panel) a bit when engine is running. They do the same at idle as they do when driving 50-60 mph. It even appears revving the engine while in neutral causes the lights to dim slightly (both headlight and tail light). Any thoughts on this? I have checked all the connections, voltage output of the alternator, the rectifier appears OK with an amp meter. Not sure if this is the way it is....
Sounds a lot like a slowly dieing R/R. Mine went the opposite way, lights brighting a lot. Have you gone through the testing procedures in the service manual for the charing system yet?
Yeah... perhaps. I purchased the bike last year... The battery looks relatively new. I went on a 2 hour drive the other night and when I checked the battery level this morning it read 13 volts with the engine off. It is a simple thing to check first however... I'll borrow a friends...
I took it off and measured the ohms as per the service manual. I get appropriate readings using pins 1 and 5 with any other pin, however nothing at all registers on pins 2, 3, or 4 using any combination.... However the readings are on the lower side of the scale. PINS:
Sorry, been a few days since I hit the site. Your battery voltage isn't bad... yet. I don't recall which wire colors go with which pins on the R/R, but this is a good generic reference: Electrex Fault Chart
I think your results are consistent with a good R/R. That said, if you have the original R/R I would go ahead the replace it. The chances of a failure are pretty high. There was a poll on here a while back asking who had an R/R failure. Most respondents did have a failure. I'd suspect the failure rate on the third gen bikes is 100%.
To address your current problem, start looking at the rest of the wiring harness. You need to look for ground shorts or anything else that is suspect. If you don't mind wading through my poor writing and wordy description of a trip, I've got pictures of my original R/R (melted) and the ground short that caused it. Here
I went for a ride the other day and the bike wouldn't restart after shutting it off... no power, battery dead. I returned home and got a spare battery and the bike started right up again, so immediately got it home. So my original tests were obviously incorrect. Could this still be a r/r problem, or simply an alternator? I don't believe these alternators work like a car do they? After starting the bike will it run properly without a battery connected? or does the bike need a battery connected at all times? If I disconnect my battery while running, it still runs just very poorly.....
If a r/r is going or gone bad, will the bike start with a charged up battery? If the r/r is bad, the bike shouldn't start at all should it, even with a good battery?
My bike was running fine until I shut it off...It wouldn't restart without replacing the battery with a charged up one.....
Definitely sounds like a bad R/R. The battery has to be connected or the bike runs rough like you stated earlier. The magneto puts out voltage at a very low amperage. It is just enough to run the bike and lights and charge the battery at the same time but the battery carries the majority of the load. The battery is an integral part of the electrical system and gives it some "oomph." I would change the R/R and the battery and you should be good to go for awhile. Even though the R/R checks good unloaded (bike OFF) it may not be operating properly when the electrical system is under load (bike running) and it will draw on the battery until dead. Just the magneto and the battery are enough to run the bike, hence the smooth running until you shut it off, but the battery is not being charged and that is why you are not able to start it until you get a fresh battery. I have been through an R/R change on both my '98 VFR and a '92 CBR. Honda makes great bikes but whoever does their R/Rs SUCKS ! ( Nippondenso, I think) Hope this helps.