Why aftermarket thermo switches are not recommended.

[firefly]

Take a look at the difference between stock & after market switches, the aftermarket ones don't reach the flow of coolant so they have a pocket of none circulating hot coolant & keep the fan on almost all the time straining the charging system, A manual switch is the better alternative, I had the aftermarket one for a few years removed it & now have the manual switch.

 

[one2dmax]

I don't think there is really any problem with the shorter design and a pocket of "hotter" coolant in that area. The water flowing across the top of the pocket and the housing assembly itself will both even out any temperatures pretty effectively.

What causes the fan to stay on is the range at which the switch operates compared to the stock switch. I mentioned to one of the guys selling these years ago that we could supply the same switch for considerably less and even have a lifetime warranty. We don't normally sell them because there is no reason since the fan stays on all the time with it.

Their reply was that they sort through the units ahead of time and get the ones out that work the best (getting rid of the ones that turn on too early). I think it was just B.S.

Anyway, I too prefer the manual switch but not for the same theory.

Sean

 

[johnpclynch]

I'm using a thermo switch from an 87-88 Nissan Sentra, part# 201-1373 I believe

I've never had a problem with it (where I used to with the original) but it looks like it has much deeper threads than the one you have shown

 

[Miles Long]

I've always been curious :ummm:about this manual switch/replacement thermo switch issue. Not about what works the best, but about WHY either is needed in the first place!
Obviously, these mods originally came about because of owner's concerns about the needle position on the temperature gauge. Sometimes close to, or in the red zone.
However - has anyone actually measured the coolant temp, and how it relates to needle position? More importantly, if the engines tend to run "hot" at times, because of thermo switch settings, fan size, whatever.........why didn't Yamaha Motor Corporation make their own factory modification, after the bikes had been on the market awhile(say '86-'88)?? Seems to me that this would be a very inexpensive change for them to make, would cut in very little to their profit margin. My guess - only a guess - is that Yamaha considered even the maximum coolant temperatures encountered to be within acceptable limits for this model of engine. Let the debate (civil , of course) begin!
Cheers!
p.s., by the way - I installed a manual switch years ago. Didn't like the looks of that temperature gauge sometimes............

 

[naughtyG]

To me it made a lot of sense in Florida. Basically, sitting in traffic in hot weather, I just wanted to be able to switch the fan on earlier, so that the bike wouldn't have to get to that 'super hot' state it would get to before the thermoswitch flipped.
It really helped keeping ME cool too - that hot air from the fan is a real pain when you're already sweating at the lights in the sun!
And, I found our that the lower temp switch was not a good idea - it meant the fan was on all the time when running hot days at 70mph+ on the highway, which in turn made my fuel consumption shit by adding load to the charging system.

 

[PDWeyand]

I also installed a manual switch on mine, the temperature gauge would rise higher than I like when sitting at mutable lights. I would not hear the fan kick in until the temp was really up there, so sitting there with no moving air to help cool the motor or coolant, I worried about the bike overheating. I do not know if the temp gauge is a direct take on the real temp of the coolant or not, I would hope so.

 

[firefly]

I've always been curious :ummm:about this manual switch/replacement thermo switch issue. Not about what works the best, but about WHY either is needed in the first place!
Obviously, these mods originally came about because of owner's concerns about the needle position on the temperature gauge. Sometimes close to, or in the red zone.
However - has anyone actually measured the coolant temp, and how it relates to needle position? More importantly, if the engines tend to run "hot" at times, because of thermo switch settings, fan size, whatever.........why didn't Yamaha Motor Corporation make their own factory modification, after the bikes had been on the market awhile(say '86-'88)?? Seems to me that this would be a very inexpensive change for them to make, would cut in very little to their profit margin. My guess - only a guess - is that Yamaha considered even the maximum coolant temperatures encountered to be within acceptable limits for this model of engine. Let the debate (civil , of course) begin!
Cheers!
p.s., by the way - I installed a manual switch years ago. Didn't like the looks of that temperature gauge sometimes............

I think Yamaha thermo switch temperature setting has to do with emissions, a hotter engine emits less emissions,

I have a water temperature digital gauge, the stock thermo switch kicks in at 226* F, on any other bike it kicks at ~ 212* F, with a manual switch I can anticipate a long wait & turn the fan on as needed. the main reason I removed the Nissan switch is that it keeps working and prevents the battery from getting fully charged with 14 volts, according to my on board voltmeter the fan when on consumes ~ 0.20 volts but when stopped in traffic & idling the charging would dip to 12.80 volts barley charging the battery. I am using the smallest radioshack toggle switch rated 3 amps, its working fine & doesn't seem like it gets overloaded.

 

[Miles Long]

I think Yamaha thermo switch temperature setting has to do with emissions, a hotter engine emits less emissions,

I have a water temperature digital gauge, the stock thermo switch kicks in at 126* F, on any other bike it kicks at ~ 112* F, with a manual switch I can anticipate a long wait & turn the fan on as needed. the main reason I removed the Nissan switch is that it keeps working and prevents the battery from getting fully charged with 14 volts, according to my on board voltmeter the fan when on consumes ~ 0.20 volts but when stopped in traffic & idling the charging would dip to 12.80 volts barley charging the battery. I am using the smallest radioshack toggle switch rated 3 amps, its working fine & doesn't seem like it gets overloaded.

So....we're making some progress with this issue! I never thought to ask about the actual temperatures showing, that people with aftermarket gauges would see.
If the OEM switch kicks in at 126*F, can it be assumed that the coolant temp. never exceeds this, providing the cooling system components are all working normally (and the system doesn't need cleaning)
If so, is this temperature within the acceptable range for this type of engine? If that is true, can we do without manual override switches and different thermo switches, ignore the stock temperature gauge, and not worry about coolant temperature?
By the way, Mr. Fly, I recently did that RR wiring modification that you have actively promoted, and it rocks! I now get 14.4 volts to the battery. Thanks!
Cheers

 

[maleko89]

Stock fan kicks on close to 190*F. I didn't put aftermarket in because I was concerned about engine temp...I did because my legs were getting fucking hot.

 

[bazwell]

So....we're making some progress with this issue! I never thought to ask about the actual temperatures showing, that people with aftermarket gauges would see.
If the OEM switch kicks in at 126*F, can it be assumed that the coolant temp. never exceeds this, providing the cooling system components are all working normally (and the system doesn't need cleaning)
If so, is this temperature within the acceptable range for this type of engine? If that is true, can we do without manual override switches and different thermo switches, ignore the stock temperature gauge, and not worry about coolant temperature?
By the way, Mr. Fly, I recently did that RR wiring modification that you have actively promoted, and it rocks! I now get 14.4 volts to the battery. Thanks!
Cheers

+1

Temp. should be above 212'f(100'c). That is why cooling systems are pressurised. They run above the boiling point of water.

Thermostat should block water flow until 188'f(87'c). Anything below 188'f is damaging the engine. A fan cutting in at 190'f indicates a faulty switch.

The air that blows on your legs is hot. It is supposed to be!
I have ridden on 115'f days. On days like that the fan cuts in when I stop at traffic lights. Thats normal. I have never noticed the fan on when riding.

If I was concerned about temp. I would take the RH scoop off and check the temp of the metal part where the radiator cap is with a $15 digital infrared thermometer.
If the fan kicks in and the temperature doesn't come down (and the fan keeps running) while I'm testing it, it means the radiator or water pump is inadequate, not the fan.

Turning the fan on early is running the engine too cool, which promotes cylinder wear.

 

[firefly]

So....we're making some progress with this issue! I never thought to ask about the actual temperatures showing, that people with aftermarket gauges would see.
If the OEM switch kicks in at 126*F, can it be assumed that the coolant temp. never exceeds this, providing the cooling system components are all working normally (and the system doesn't need cleaning)
If so, is this temperature within the acceptable range for this type of engine? If that is true, can we do without manual override switches and different thermo switches, ignore the stock temperature gauge, and not worry about coolant temperature?
By the way, Mr. Fly, I recently did that RR wiring modification that you have actively promoted, and it rocks! I now get 14.4 volts to the battery. Thanks!
Cheers

I made the correction on the initial post its 226*F not 126*F, yes temps can go up to 230* F, in my vapor speedo I have two levels of warning lights, I set the amber light at 226*F (when the stock fan kicks in) and 230*F as dangerous level the red light turns on.

when the stock temperature gauge needle is at the middle the vapor temp reads 210*F I try to keep temps at that level and turn the manual switch on if I am still idling in traffic.

 

[firefly]

Stock fan kicks on close to 190*F. I didn't put aftermarket in because I was concerned about engine temp...I did because my legs were getting fucking hot.

Theoretically the fan should close at 190* but these things are analog and not very accurate, on the vapor speedo temp gauge the fan starts at 226*F +/- 2 to be accurate. I think the most beneficial temp measurement should be oil temperature.

 

[bazwell]

Firefly, is your engine modded?
I really like the fact that you have a proper temp. readout.

 

[firefly]

Firefly, is your engine modded?
I really like the fact that you have a proper temp. readout.

No my engine is bone stock.

 

[2fear]

Good reading, great thread.....

 

[bazwell]

230'f certainly sounds like a good number to keep it below.
Maybe 226'f starting of the fan is too high.
But then you come back to the initial problem.

What you need it to be able to turn the fan on when the amber light comes on. Then you can just adjust it!

 

[firefly]

230'f certainly sounds like a good number to keep it below.
Maybe 226'f starting of the fan is too high.
But then you come back to the initial problem.

What you need it to be able to turn the fan on when the amber light comes on. Then you can just adjust it!

With a manual switch as I come to a traffic jam I flip the switch on then turn it off as the road opens, I think this is the most efficient use of the fan without having it working when its not needed, on most bikes the fan kicks at 212*F which on max is the middle of the stock gauge. keeping the temperature at that level is by no means over cooling, also monitoring how fast the fan cools the engine gives an idea about the health of the cooling system, if temperature stays high even when the fan is on that alerts me of problems like leaking or worn radiator cap, stuck thermostat or other engine problems. I also took a temperature reading on an open road, the coolant temp stays ~ 198*F at an ambient temperature of ~ 70*F.

The Vapor speedometer I have provides much more information vs the stock speedo, I don't think I'll ever go back to the stock speedo.

 

[misiek93]

The Vapor speedometer I have provides much more information vs the stock speedo, I don't think I'll ever go back to the stock speedo.

Do you have a picture of the speedo you're using? I have a digital one that only tells me the speed but I'm thinking of upgrading to a more advanced one maybe with an RPM gauge as well, not sure yet.

 

[firefly]

Do you have a picture of the speedo you're using? I have a digital one that only tells me the speed but I'm thinking of upgrading to a more advanced one maybe with an RPM gauge as well, not sure yet.

http://trailtech.net/motorcycle_vapor_kits.html

 

[misiek93]

http://trailtech.net/motorcycle_vapor_kits.html

That looks pretty good. Thanks for the link.