What's the deal with the temperature gauge?

[BlackAndBlue]

I realize that most automobiles have coolant temperature gauges that are "rigged" in the sense that they show the same position for a decent range of operating temperatures so that people don't think there's a problem when they see it go up and down. Obviously, the FZ6 does not have that. Since I've been riding my FZ6, I typically see it around 160* while I'm actually operating it. If i let it idle, I've had it climb as high as 207, which is pretty much too hot for coolant in most cases. The strange thing was that the radiator fan still didn't come on even when it got so high. I've actually never noticed it come on. So why does it stay so low yet spike so high without even turning the radiator fan on? Is it maybe broken? Does anyone know what temperature the thermostat is set to keep the coolant at? Does the temperature gauge on the dash even show coolant temp? Or is it oil?

 

[dpaul007]

That's not too hot for coolant. I believe my fan has kicked on around 212 F, cools it down to a certain temp and turns off. It's been a handful of months since I've been on my bike, so I don't know the exact numbers

 

[ChanceCoats123]

For water at 1 atm (at sea level) it boils at 212 F. Since coolant systems are mixed with a coolant that has a higher boiling temp, AND the coolant systems are pressurized, it's not uncommon to see coolant temperatures spike over 212 F and the fan probably won't kick on until it's close to boiling just to save energy.

 

[BWillie]

212 Fahrenheit is the boiling point of water in atmosphere (100°C)

Pressurized coolant can exceed that temperature considerably without boiling, but most vehicles will get to 100°C (212°F) before the fan switches on anyway, and switches off when it reaches 93°C or so.

 

[FinalImpact]

210 - 212°F is the number to beat (fan on). Let it idle longer and confirm it does come. Mine cools to 207 or so and fans off.

Stat opens around 162F. So its all pretty normal. It takes about 35mph to maintain cooling and riding with a 35mph wind offers no cooling until you turn away!

Its a small system so it fluctuates a lot.

 

[BlackAndBlue]

I understand about the boiling point. Most cars that I've dealt with have had the fan cut on somewhere below 200 though to keep the temperature closer to the 170-190 or wherever the engine was meant to run. I'm sure I'll see the fan work in the summer then.

 

[Ultrarandom]

Most definitely sounds right. When I'm sitting in traffic (mine is in Celsius) my fan kicks on at 100 and then cools down to 95 before it shuts off again. Usually if I can maintain speed it does sit at around 72 though (which is thermostat temp). I know in my old car as well I put a thermo switch in which would cut in at 95 and cool it to 88 before switching off so these temps aren't really that high. Some Honda cars (from what I remember, don't tend to deal with them) go even as high as 112 before fans kick in. All depends on the engine itself and what it's designed to handle

 

[BlackAndBlue]

i guess i've just dealt with cool running engines or i'm not remembering correctly. The FZ6 definitely has a different strategy of a cooling system than my Miata though; it has a 192.5* thermostat and the fan definitely turns on before 212 but I don't remember exactly where. I think it's 200.

 

[Vertigo]

Mine is similar to others. Fan kicks on around 207-212 and then cools it back down. I had a 94 vette that was about the same(might have even went to 215-220 can't remember). Probably just depends on the maker and what they feel their equipment can handle.

 

[iviyth0s]

210 - 212°F is the number to beat (fan on). Let it idle longer and confirm it does come. Mine cools to 207 or so and fans off.

Stat opens around 162F. So its all pretty normal. It takes about 35mph to maintain cooling and riding with a 35mph wind offers no cooling until you turn away!

Its a small system so it fluctuates a lot.

I always hated how low the TS opens on this bike, if it's cold out the bike struggles to get higher than high ~167F (74C-76C) and mileage is god awful. Same problem my car had when I got it, because it had a stuck open TS, and the new one (set for 195F) noticably increased my mileage. WTH Yamaha!

 

[BlackAndBlue]

I wonder if there's a hack around that. The cardboard in front of the radiator that people do on deisels all the time maybe.

I guess that what I still can't figure about the situation is that while most automobiles try to stay as close to the ideal temperature as possible and very within a range of 20 degrees or so, the fz6 regularly runs anywhere within a range of 45 degrees. As the previous poster points out, it's less than efficient. There's probably a good reason for it, but it eludes me.

 

[iSteve]

Don't put cardboard over your radiator the Yamaha engineers know what they are doing. You are comparing motorcycle systems to auto systems. If you compared your FZ6 to other motorcycles you would see this is all normal operation.

This is the exact reason auto manufactures use slow reacting gauges in their cars.

 

[Dry Martini]

Don't put cardboard over your radiator the Yamaha engineers know what they are doing. You are comparing motorcycle systems to auto systems. If you compared your FZ6 to other motorcycles you would see this is all normal operation.

This is the exact reason auto manufactures use slow reacting gauges in their cars.

No they use slow reacting gauges because most car owners are stupid. The first gen miata had a real oil pressure gauge. Then in 95 they changed to an idiot gauge because too many owners began questioning why the gauge was "fluctuating".


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[The_Paragon]

Hahah, Read the owners Manual...

I believe Yamaha doesnt state concern untill temps reach 220 or 240F...

They're built to be hot running motors.

My car would would be blowing gaskets at that point!

 

[FZSexy]

lets see....600cc high performance I4 motorcycle engine kicking out 100hp and goes to 14,000rpm. should be running cool in mid summer imo

i once asked a yamaha tech what the engine temp range should be. dude looked at me and said "hot". the tech next to him said "and hotter"

 

[FinalImpact]

Its tempting to throw a 180°F ish stat in there to reduce wear. Im sure something would fit. The problem is it needs to be fully open at say 190°F so thats a tight window. OEM is 160 = fully closed, 185 = fully open.

With ambient temps in the mid 60F, it maintains low 16# far to often. Making it a good candidate for increased wear and oil sludge (unlikely due to quality and & OCI). Mine being ah "unrestricted" (S2), it no longer runs as warm as it used to. Needless to say, it bothers me enough to mention it so, ya - been thinking about it.
See sig for ref to restriction.

 

[Dry Martini]

Its tempting to throw a 180°F ish stat in there to reduce wear. Im sure something would fit. The problem is it needs to be fully open at say 190°F so thats a tight window. OEM is 160 = fully closed, 185 = fully open.



With ambient temps in the mid 60F, it maintains low 16# far to often. Making it a good candidate for increased wear and oil sludge (unlikely due to quality and & OCI). Mine being ah "unrestricted" (S2), it no longer runs as warm as it used to. Needless to say, it bothers me enough to mention it so, ya - been thinking about it.

See sig for ref to restriction.

Interesting. There was a story a few years back in one of the Moto rags about Moto courier in London reaching a million miles on an R1. Now assuming the R1 does not run quite as hot as an R6, it may last longer than the R6. So let's assume the stock R6 is good for 600,000 miles, is increased wear all that big a deal?


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[FinalImpact]

Interesting. There was a story a few years back in one of the Moto rags about Moto courier in London reaching a million miles on an R1. Now assuming the R1 does not run quite as hot as an R6, it may last longer than the R6. So let's assume the stock R6 is good for 600,000 miles, is increased wear all that big a deal?


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IDK!

Its all about the design clearances. For example: at ambient room temp ~70°F the engines piston to cylinder wall clearances are checked. As are the piston ring clearances (end gap). The piston, rings, cylinder all expand with heat and meet some target temperature where the parts are now **supposed to be size wise** (i.e. thermal expansion) at there proper clearance. Not to tight or too loose. But ideal.

Point: cold starts induce more wear than 10,000 miles on the interstate.
Engines which run too cool or are subject to repeated short trips show greater wear than those going 50 miles round trip and being shut off.

160 seems very low but I have no facts to suggest its doing harm. It just seems very low.
- Although if one looked at it differently: if the OIL TEMPERATURE INCREASES while COOLANT temps are low, yet OIL temperature decrease while the COOLANT is near say 195°F, is that an indication that the clearances are too tight, as in increased friction raising oil temps??? Maybe!?!
- just thinking out load... thoughts?

 

[Dry Martini]

My thoughts on the subject are, the quality of the engine builds is so good that for normal driving, they will last for more miles than I will ever be able to ride, due job and other non-moto obligations. So if my FZ6 only lasts for 400k miles, I will not be disappointed.


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[iviyth0s]

IDK!

Its all about the design clearances. For example: at ambient room temp ~70°F the engines piston to cylinder wall clearances are checked. As are the piston ring clearances (end gap). The piston, rings, cylinder all expand with heat and meet some target temperature where the parts are now **supposed to be size wise** (i.e. thermal expansion) at there proper clearance. Not to tight or too loose. But ideal.

Point: cold starts induce more wear than 10,000 miles on the interstate.
Engines which run too cool or are subject to repeated short trips show greater wear than those going 50 miles round trip and being shut off.

160 seems very low but I have no facts to suggest its doing harm. It just seems very low.
- Although if one looked at it differently: if the OIL TEMPERATURE INCREASES while COOLANT temps are low, yet OIL temperature decrease while the COOLANT is near say 195°F, is that an indication that the clearances are too tight, as in increased friction raising oil temps??? Maybe!?!
- just thinking out load... thoughts?

I've noticed obvious harm...to my fuel economy! lol