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Discussion Starter #1
I was riding around the park very slowly the other might (5-10mpg) and noticed the temp gauge was right on the to of the normal range, on the line for "Hot" a couple times. If I accelerated up to about 30mph it cooled down right away. Also, if I stopped it seemed to slowly come down. When I got home I left the bike running in my driveway and the fan came on around the 3/4 mark and kept the bike around the 1/2 mark on the gauge. So is there just a middle speed where the fan does not operate but there isn't enough airflow over the radiator? (I could only check the fan by stopped and looking at it but when I did it ran and the bike cooled down).

-Robert
 

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romeobravo172
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Damn Robert, your gas milage sucks!! (LOL) You can tell when your fan is running, like say at a stop light, you will feel hot air blowing on left leg.
 

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The fan turns on and shuts off stricly by temperature sensed by the fan switch. The fan switch will supply a ground to the fan relay if the temp gets to hot, thus turning on the fan. the fan switch is located on the left side of the radiator (bottom).
 

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Discussion Starter #5
The fan turns on and shuts off stricly by temperature sensed by the fan switch. The fan switch will supply a ground to the fan relay if the temp gets to hot, thus turning on the fan. the fan switch is located on the left side of the radiator (bottom).
Ok. So, unlike a car there is no speed cut off?

-Robert
 

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Crap, I WAS in 5th gear.
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Ok. So, unlike a car there is no speed cut off?

-Robert
There is no cut-off. The fan will run whether the key is on or not. Sounds like you have a finicky switch, relay, or wiring, or fan.

Incidentally, one argument for lane-splitting is that air-cooled bikes will overheat when sitting in traffic.
 

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Discussion Starter #7
Curious, when riding around in a hot day in stop-n-go type conditions, what temps do you normally see? (what range, how much does it vary, etc).
 

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Crap, I WAS in 5th gear.
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Curious, when riding around in a hot day in stop-n-go type conditions, what temps do you normally see? (what range, how much does it vary, etc).
In my experience, "Normal" range on the 750 is 1/8 to 3/4! On a hot day I usually see 2/3-3/4 or a little more depending on speed, etc. I have had the bike since new and it's always been this way.
 

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My '00 has never gone over 1/2 way, even when it's 90+ and I'm stop and go, with the go part about 20mph for 6-8 miles. Like I was this past weekend. Fan kicks in and runs ok and some times runs for 20-30 seconds when I shut her down. But it does take me about 4 or 5 miles most days just to get her in the normal range too. I figure I either have a stuck open thermostat or none at all, but as far as I know this is nornal. No 750' around here to compare it to. Just don't know. Haven't check it and don't plan to unless I really have to.
 

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My 93 has only gone over half way once or twice. I noticed that if I'm at either extreme on the rpm gauge, she heats up. If you were only doing 5 to 10 mph in a parking lot, you're rpms were prolly really low but the throttles engaged. I know when I kept my rpms really low, like in stop-n-go traffic, the heat gauge would go up pretty quick. When it opened up into a good stretch of road, I'd keep the rpms in the middle range regardless of what gear I was in. She'd get some air and cool down just as quick. The way I rode was how I balanced and maintained the engine temp, I just took that as part of the technique involved. That's what you gotta do with a helicopter too, I just transferred it. If you practice hover techniques for too long and don't take a trip around the pattern every so often, she'll overheat big time.
 

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Speed has nothing to do with it....ambient air tempature and humidity do.

For example, your motor will cool at the same rate if your going 30mph in 60 degree weather or 60mph in 85 degree tempature.

Your fan simply kicks on when the engine tempature gets to a certain point, regardless of how fast you are going.

I never felt the fan blowing on my leg, the only time I heard or knew the fan was on was when it ran after I stopped the bike on a hot day. My temp gauge never went over the middle mark, so I can only assume it ran when needed.
 

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Discussion Starter #12
Can anyone confirm that the sensor that detects temp for turning on the fan is the same one that provides feed to the temp gauge?

-Robert
 

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Steve
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I think they are different. The temp guauge is under the tank near the radiator cap. The fan switch is on the bottom left of the radiator.

My bike runs hot all the time. I have replaced the thermostat, radiator cap, fan switch, and of cause coolant twice. I even have replaced the Tach and with it the temprature guauge. It still get to the red in traffic, so I installed a user fan override switch to turn the fan on before it gets too hot.

I think I will need to flush her out again as there is nothing else left to do.
 

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I think they are different. The temp guauge is under the tank near the radiator cap. The fan switch is on the bottom left of the radiator.

My bike runs hot all the time. I have replaced the thermostat, radiator cap, fan switch, and of cause coolant twice. I even have replaced the Tach and with it the temprature guauge. It still get to the red in traffic, so I installed a user fan override switch to turn the fan on before it gets too hot.

I think I will need to flush her out again as there is nothing else left to do.
That is a great idea. I am going to install a user switch on mine. I have noticed that my temp runs up a little high. Not in the red but close when sitting in traffic.
 

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Sparky!!!
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The fan switch is located at the bottom clutch side of the radiator, the Temp Sending unit for the gauge is a single wire next to the thermostat.
 
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