[geargrinder]

Still trying to determine what is excessive heat on my dad's alternator. With the motor warmed up and the headlight and tail light fuse removed, alternator heats to 110F degrees, (not bad, definitely touchable). Plug the fuses back in and temp. goes to 140F. NOW, that sucker's HOT! FYI, New stock alternator, battery checks out, charges w/in specs fine. Will say one thing, when you pull either the headlight or taillight fuse out the motor rpm speeds up at least 500 rpm. As always, thanks everyone!

 

[Bamaeagle]

Hmmmm...never thought about it.....

The alt is connected to the engine and the engine can get really hot. Hey as long as it is not giving you any problems i would not worry about it.

Just my .02....worth....

 

[trike lady]

What wattage headlight bulbs are currently being used?
The bike normally runs with a pair of 45/45 wattage bulbs.

 

[Cantankerous]

Why was the original alternator changed?

 

[Dookoo]

Probably nothing to worry about for everyone else until someone gets a baseline temperature on an operating alternator. I've seen them hot enough to boil water and function fine. I would get a temperature reading but my Wing is currently apart.

 

[LarryinSeattle]

500 rpm is a lot. Sounds to me like you have some voltage drain off in your lighting circuit. Take your headlight bulbs out and see what it does then. Make sure you have the right size fuse in that circuit. Previous owner could have upped the fuse size to keep the lights on. This can cause a fire.

If you remove the fuse, it eliminates the entire circuit. Removing an element of the circuit will help you determine the problem.

If you ride it long enough in that condition, it will show its self soon enough, possibly in smoke and fire.

 

[Ron Robertson]

Given that there will be heat transfer from the engine to the alternator and the ambient temperature will drive the base heat of the alternator. The add current draw of the accessories (Current flow (I) times voltage applied (V) = Watts (W) of energy(heat) produced) or I x V=Watt.
Every time something is added to the current draw additional heat is produce. Two 45 watt head lights =90 watt total at 12 volts will draw 7.5 amps of current. Every amp of current flow increase the heat.
As to why the RPM changes when the fuse is pulled. The alternator is an Electro, Magnetic device. The spinning coils in the Magnetic Fields of the Alternator appose the in the increase
of current flow put, which puts addition load on the engine. Remove the load the engine speed will increase some. How much ???.
Things to Check.
1.The voltage across the battery with the bike running. Should be 13 to 14.3 volts.Anything over 14.3 volt, could be an alternator problem.
2. Is the battery hot to the touch. Hot = over charging Alternator
3. Is the battery swollen or bulging ? yes = over charging
4. If it's a wet cell battery does it require water to be added frequently ? yes = over charging.

 

[drmcmtru]

Check the alt. temp. on a car or truck ?? Making electricity makes heat. I don't believe you have a problem. The 500 rpm rise is probably not out of line on a carbureted bike. If was injected it would maintain its speed when the load removed. If having no other issues i would leave things be. '94SE

 

[budoka]

Even 140 doesn't seem overly high to me. I'm more concerned wth the apparent draw when you plug the fuses back in. +500 rpm does sound excessive to me.