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Discussion Starter · #1 ·
Hi, so my '98 VTR Firestorm was in need of a rectifier as the one in it wasn't recharging properly and was running super hot. As parts for these bikes are pretty scarce where I live, I had to resort to an unbranded rectifier which is said to be compatible with the CBR 600 F4i. All pins of this new rectifier matches the one I removed from the VTR. I brought it home, plugged in and started the bike and the bike runs great. Checked the charging voltages with a multi meter and it seems to be doing the job right as well. However the rectifier runs super hot even after running the bike for a couple of minutes on Idle. I would like to know if this is normal on these bikes as I got no second working rectifier to compare. Does the OEM ones run hot like this too? Is my new rectifier faulty even though it is regulating correctly? Are overheating issues common in these rectifiers and is it ok to keep it on? if so is there any way to improve the cooling?

Some insight would be helpful. Thanks.
 

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I'm not sure what 'super hot' is, but most RR's run hot - that's why they have cooling fins and are usually placed somewhere up front of a bike to get the cool air.

I probably wouldn't worry too much as it is charging correctly. But maybe somebody with the same bike can chime in.
 

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Regulator/Rectifiers generate heat, thus the fins. Depending on where is located in a motorcycle, whether is more or less exposed to flowing air, would make temperature varies. Some riders have reported 200F, measured with an infrared thermometer.

.....all that said, current is what relates to temperature. I'd start by checking charging voltage (about 14VDC), and then check for any loose or corroded connection which would increase current consumption, starting with the battery connections.
 

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Discussion Starter · #6 · (Edited)
I'm not sure what 'super hot' is, but most RR's run hot - that's why they have cooling fins and are usually placed somewhere up front of a bike to get the cool air.

I probably wouldn't worry too much as it is charging correctly. But maybe somebody with the same bike can chime in.
Regulator/Rectifiers generate heat, thus the fins. Depending on where is located in a motorcycle, whether is more or less exposed to flowing air, would make temperature varies. Some riders have reported 200F, measured with an infrared thermometer.

.....all that said, current is what relates to temperature. I'd start by checking charging voltage (about 14VDC), and then check for any loose or corroded connection which would increase current consumption, starting with the battery connections.
They are supposed to get hot, normal.
Try to ride the bike and then check again , pretty sure wont be that hot with the air cooling it.
Hi. Thanks for responding. I understand rectifiers do get warm. I have a Honda VT250 as well and its rectifier does get hot, but you could touch it without burning yourself. The issue I have here with this one is you could burn your fingers as if you touched a hot plate or something. I fear it could even melt the wires going to it. And this is after running it for a couple of minutes.

I doubt the airflow could keep it down as the rectifier is pretty tucked in and the air flow looks minimal. I couldn't ride the bike today. Guess I'll have to confirm this another day.

My dad had a look into this and stated maybe its the somewhat large battery I'm running on the bike (12V 12Ah). But this battery size is what I see as recommended so I'm not sure about it.
 

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A larger battery would not affect it at all. RR is just getting rid of excessive voltage from the stator through heat .
If it gets that hot that immediately burns your finger does not seem normal . Usually is hot like touching the car's bonnet after driving .
Having minimal airflow its bad .. some people make holes to the fairings to increase air flow or just move it where it has more airflow .

Measure RR DC voltage on Idle and when revving , do the same for the stator AC output .
 
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