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Discussion Starter #1
Last night I took my bike out and the bike ran hotter than it normally does at least on my bike. I am not sure but I think temp sensor is working correctly as the fan will turn on in the middle of the night. So i have to unplug the connector at the base of the radiator.

I opened my reservoir and it was boiling thinking this isn't what it is suppose to be doing.

Please point me in the direction to troubleshoot this. Not too familiar with this.
 

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well, the fan running in middle of night (going to assume the engine is cold), and pulling the wire on the radiator stops it from happening.. thats a bad fan switch (in all likelyhood).

overheating...

temp guage is a different sender, mounted on the thermostat housing (right side of frame, up under tank/right neck cover). what was it reading when you looked in the coolant tank?

thermostats do fail on these, and there is an 'automotive' application that is a direct replacement, but I forgot what one it is. sure someone will chime in here.
 

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Discussion Starter #4
Ok I took my bike out today andit stayed pretty much in the right place on the thermostat reading. I stopped my bike at a friends house and left it running. it began to overheat and water began to pour out the bottom. The reading was close to the read part of the gauge. The fan was running. After I got back on the bike and riding a bit it cooled back down.

The question I have it this. Can the thermostat not open and the sensor still work right. Also can the engine cool down alone by riding and cooling the fins with air and the thermostat still not open.

I haven't had this problem until last night.
 

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Ok I took my bike out today andit stayed pretty much in the right place on the thermostat reading. I stopped my bike at a friends house and left it running. it began to overheat and water began to pour out the bottom. The reading was close to the read part of the gauge. The fan was running. After I got back on the bike and riding a bit it cooled back down.

The question I have it this. Can the thermostat not open and the sensor still work right. Also can the engine cool down alone by riding and cooling the fins with air and the thermostat still not open.

I haven't had this problem until last night.
yes, riding it can cause temp to go down, but not by cooling the fins on the engine. its the air thru the radiator that cools it down when riding. the fan alone is not always enough to keep it cool, when going low speeds or stopped.

temp sensor can read correctly regardless of the thermostats position or condition (bad or good). its on the 'hot' side of the thermostat if I recall.

if riding causes it to cool down, then look at a partially plugged radiator, causing less coolant to flow at idle (riding is done at higher rpms than idle, and therefore there is more water flow avail to go thru the radiator).

if the fan is cycling on and off properly (and if the radiator is doing its job it should cycle, even at idle), then the only thing that can really cause your issue is either a plugged (internal, or external, check the front for debris) radiator, or a failing thermostat (probably stuck partially open, or wont open fully).

I suppose a water pump thats marginal could do it, but thats pretty much a stretch, since when its ridden, it cools.

all of this is of course assuming there are no air bubbles in the cooling system
 

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FREEBIRDS MC CENTRAL NY
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If the radiator fins are plugged get condenser coil cleaner for refrigeration units.they have it at Lowe's
 

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Replace the bad fan switch first.

35 mph or better would keep mine cool in hot weather, but any stops at red lights would heat it up quick without the fan.
 

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Discussion Starter #8
The fan is working. It just has a mind of its own. But I do want to make it work correctly. So where is the fan switch or is it the piece that is near the thermostat?
 

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Discussion Starter #11
wow just checked with the dealer and the price on the fan switch is over $100. I will be placing a switch inline to make my fan run all the time after I crank my bike. That is way too much.
 

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You should ask Kanuck, he was stripping one.

They are usually cheap on ebay, but right now all I see are $39-45, even $300 from Caltric.. lol @ Caltric

Charge volts drop when the fan runs, good luck with the full time fan.
 

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Discussion Starter #14
what is the deal with the amprege on the bike. The amps on the bike keeps the voltage at the right condition when other things require voltages. What is the output specs on the stator?
 

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Discussion Starter #16 (Edited)
that rating is at 8000 rpms. I wonder what it is at 5k. If it is even close to that then there are wasted amps getting lost in the regulator. If that was the case, it might be advantageous to build a secondary rectifier/regulator that would allow us to use more of the amps that aren't accessible to put our accessories on it and eliminating it from the fuse panel.

It will also allow us to have greater voltage to the firing and charging of the battery. Ok maybe not more but we wouldn't lose the voltage when the accessories are used if we use an alternative rectifier.

I will have to look into that.
 

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the best regulator option thats easily available for our bikes is to change out the stock unit for a MOSFET unit. its more effecient at converting the AC from the stator into DC the system needs. many people get full 14+ volts at idle with one. Stock RR will need 3k or more in most cases to get up to 14 volts output.

a little quick math (and I may be wrong here, its been years since I actually had to apply ohms law for any real purpose), is the system has about 330 watts total output (regulator output). I guesstimate the system load around 100W without factoring ingition load, and cooling fan (this is low beam on, no brake light/turn signals active, other lighting in dash). that leaves 200 w avail for engine and accessories. I think, someplace I have read that the acc load should be kept to 10 amps total load.. that leaves about 80W left to charge battery and run engine.. that aint much extra. the stator just isnt wound with heavy enough wire to provide more current to supply the loads
 

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Go to Auto Zone get an adjustable thermostat. Put the bulb through (inside the hose) the upper radiator hose and tighten the clamp tight. Run the wires to the fan and adjust the temp that you want the fan to come on. I used this set up on my pick up. I used a relay, but you may not need one on a smaller fan.
 

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Go to Auto Zone get an adjustable thermostat. Put the bulb through (inside the hose) the upper radiator hose and tighten the clamp tight. Run the wires to the fan and adjust the temp that you want the fan to come on. I used this set up on my pick up. I used a relay, but you may not need one on a smaller fan.
Same setup on my truck, except the bulb/probe is mounted on the fin surface.

Roasted the first controller running it a couple years with no relay. I'd think the bike fan does run a lot less amps. Last one was about $15, relay $5.

If I run the heater in winter, my truck fan never kicks on until I shut down.
 

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Discussion Starter #20
I went on a 90 mile trip this past weekend with my wife on the back and the only issues we had were our butts hurting after not riding for a while.

The temp stayed where it normally would stay. But I am still curious if the thermostat sensor maybe messing up. I will keep an eye on it.
 
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