More Observations On Undercharging

[RolandHTG]

After replacing the stator on my 99 in March I have had mostly normal charging, after a typical ride the battery ends up fully charged (12.9-13.1) But in early summer I got caught in Interstate traffic jam after running at about 85-90 for about 10 minutes. The coolant gauge went nuclear: 251 F then flashing. I quickly got going again and got it cooled down to 220 within a minute or so. NO apparent problems at that point but on several subsequent occasions when the the engine was very hot due to hard running the charging volatge dropped to around 12.2 and as low as 11.9. On these occasions I stopped and pulled the headlight fuse in order to avoid getting stranded. In the process of doing this I noticed a couple of things I was not previously aware of. 1) Coolant temperature was not a direct factor. I had previously though the large drop in charging voltage was due to the radiator fan running. But on the last two occasions the collant temperature was normal, in the 180s. Also, with the seat off to pull the fuse I was able to feel the R/R. It was warm but NOT hot. The battery is 9 weeks old. I replaced my 3 year old Westco even though it seemed to be fine just in case it was a factor. No difference.

The one circumstance that was present during each of the last three undercharging episodes is that they each followed several miles of very hard running, as in climbing steep grades at high RPM, trying to keep up with liter sportbikes with fast riders.

I intend to try to run the R/R and stator multimeter tests, especially the A/C output test under the hot engine/undercharging condition. But now back in the flat lands this may be a challenge.

Ricks is now stocking a new stator for 5th gen VFRs, price is $140 but I don't want to order until I am certain of the problem. When tested after the first undercharging episode in June the R/R and new stator tested OK and I am guessing it still will unless I can get the engine good and hot.

[Mac Morgan]

After replacing the stator on my 99 in March I have had mostly normal charging, after a typical ride the battery ends up fully charged (12.9-13.1) But in early summer I got caught in Interstate traffic jam after running at about 85-90 for about 10 minutes. The coolant gauge went nuclear: 251 F then flashing. I quickly got going again and got it cooled down to 220 within a minute or so. NO apparent problems at that point but on several subsequent occasions when the the engine was very hot due to hard running the charging volatge dropped to around 12.2 and as low as 11.9. On these occasions I stopped and pulled the headlight fuse in order to avoid getting stranded. In the process of doing this I noticed a couple of things I was not previously aware of. 1) Coolant temperature was not a direct factor. I had previously though the large drop in charging voltage was due to the radiator fan running. But on the last two occasions the collant temperature was normal, in the 180s. Also, with the seat off to pull the fuse I was able to feel the R/R. It was warm but NOT hot. The battery is 9 weeks old. I replaced my 3 year old Westco even though it seemed to be fine just in case it was a factor. No difference.

The one circumstance that was present during each of the last three undercharging episodes is that they each followed several miles of very hard running, as in climbing steep grades at high RPM, trying to keep up with liter sportbikes with fast riders.

I intend to try to run the R/R and stator multimeter tests, especially the A/C output test under the hot engine/undercharging condition. But now back in the flat lands this may be a challenge.

Ricks is now stocking a new stator for 5th gen VFRs, price is $140 but I don't want to order until I am certain of the problem. When tested after the first undercharging episode in June the R/R and new stator tested OK and I am guessing it still will unless I can get the engine good and hot.

[Mac Morgan]

After replacing the stator on my 99 in March I have had mostly normal charging, after a typical ride the battery ends up fully charged (12.9-13.1) But in early summer I got caught in Interstate traffic jam after running at about 85-90 for about 10 minutes. The coolant gauge went nuclear: 251 F then flashing. I quickly got going again and got it cooled down to 220 within a minute or so. NO apparent problems at that point but on several subsequent occasions when the the engine was very hot due to hard running the charging volatge dropped to around 12.2 and as low as 11.9. On these occasions I stopped and pulled the headlight fuse in order to avoid getting stranded. In the process of doing this I noticed a couple of things I was not previously aware of. 1) Coolant temperature was not a direct factor. I had previously though the large drop in charging voltage was due to the radiator fan running. But on the last two occasions the collant temperature was normal, in the 180s. Also, with the seat off to pull the fuse I was able to feel the R/R. It was warm but NOT hot. The battery is 9 weeks old. I replaced my 3 year old Westco even though it seemed to be fine just in case it was a factor. No difference.

The one circumstance that was present during each of the last three undercharging episodes is that they each followed several miles of very hard running, as in climbing steep grades at high RPM, trying to keep up with liter sportbikes with fast riders.

I intend to try to run the R/R and stator multimeter tests, especially the A/C output test under the hot engine/undercharging condition. But now back in the flat lands this may be a challenge.

Ricks is now stocking a new stator for 5th gen VFRs, price is $140 but I don't want to order until I am certain of the problem. When tested after the first undercharging episode in June the R/R and new stator tested OK and I am guessing it still will unless I can get the engine good and hot.

I've heard that the brake lights pull alot of current

[squirrelman]

always inspect the 3 yellow-wire plug between stator and VR for burning/melting and also the wires at the plug onto starter solenoid for melting

[HispanicSlammer]

Well I have to relate my personal story, I bought a signal dynamics volt meter with an LED single light display. It changes different colors when the voltages change. I was having the same deal - the bike would get hot and the voltmeter would show RED. So I got home tested it with my standard voltmeter and it showed proper voltage. I concluded it was a bad RR, so I took out my spare and installed it. Same thing! Turned out to be a bad Relay to my accesory fuse block - where I connected my signal dynamics meter. I thought it odd that when I was riding it would flash red one minute and green the next, especially when I was riding in the twisties and leaning it over hard. So I removed the lead on the fuse box and applied it directly to the battery, no more flashing red warnings, for an entire 500 mile trip. The Bad relay would make intermittant contact and get poor voltage.

[Guest Jonchilds]

If you're at all inclined to ride frequently on bumpy roads (or land wheelies a little hard), and the radiator overflow bottle hosing is routed anything like the 6th gens, then you may have a piece of hosing rubbing against the radiator fan, preventing it from turning at full speed.

This would describe increased current drain, and the higher temps (which dropped when moving, but didn't cool right off).

I've also increased the idle on my 6th gen to about 1500rpm to prevent too much drain when in traffic with the fan coming on/off with brake lights and indicators going.

[vfrcapn]

Have you done the wire upgrades/bypass from the electrical thread, http://www.vfrdiscussion.com/forum/index.php?showtopic=29975 ?