What is this and why is it burning f$%^ing hot

sorry to asking a stupid question again i know i really need a manual i will get one i promise but can anyone tell me what this is? and why its so dam hot? hotter then the motor burn your dam hand hot.  I just rejet the carb stuck it in the bike flipped her on let her run a little  everything seemed good had to set the idle way down.  Oh had the bike on a battery tender for about a week if that matters don't think it dose that thing wasn't hot when putting carb in


looks like it would be a voltage regulator 

not 100 percent I don't have your model

That's the regulator / rectifier , its body is a heat sink, and yes it will get hot.


If your battery is charging, its working. You may want to look up the "free power mod."

ok cool thank you for your reply's i just wasn't sure it seemed to get hot so quick and so close to your leg didn't make sense scared me a bit

This is interesting... I often charge my battery before using the bike so you would expect my regulator / rectifier to get very hot also but it never seems to..


Maybe if your link to the battery is extremely weak the R/R is working very hard to keep the voltage down and thus getting very hot.


Unless others on here chime in, I would say that it getting very hot just on idle is an issue.

Edited by DrzDick

Thinking back I'm pretty sure that when I had a scope on my battery I could see that my R/R was hardly firing at idle so very little heat should be present.


First thing I would do it hook a DVM to the battery and see what readings you get at idle and as the revs climb.


Here is vid of a me doing the test.

When I switch my dipped beam on the voltage doesn't drop showing that I have a strong connection from my R/R to my battery.

When I switch to high beam I've wired both bulbs to come on (2x 55W) so that is why the battery voltage drops. The stator can't produce enough power at idle but see how with only a small increase in revs the voltage returns back to 14 quickly. That's is a healthy stator and a strong link - this is after doing the free power mod.



Edited by DrzDick

every watt the battery doesn't get, and the headlight doesn't use, gets burned up by the VR as heat. 


it shouldn't be that hot. 

every watt the battery doesn't get, and the headlight doesn't use, gets burned up by the VR as heat. 


it shouldn't be that hot. 

Actually the VR doesn't do very much of the burning, it's a high amperage/low resistance switch. It's the stator coils inside the engine that do most of that.

If the R/R is getting hot then it could mean that it's dying.

If so it's best to find out before it has a chance to let the battery go flat, which will kill that too.

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