Temp Gauge

ofdave

Member
Always like to know what's going on with engine temp.
Our CTX doesn't have a gauge so I dug around and found one to use.
https://www.amazon.com/gp/product/B009D3HXEG/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
Went out for an hour and a half today to see how it works. Outside temp was 81* Engine temp before starting was 77* (water in the hose where the sending unit is).
Half a mile only 79 got about a mile and it was 109-mile or so later 177.
Cruising at 3000rpm it was 179-181. Rolling at 4000-4500 is was 188 or so.
Is it accurate? Don't know. What should the temp be? Don't know but the thermostat opens at 183.
This gives me a base to go by, 's all I wanted.
When I got home I sat and idled in the driveway-it slowly crept up to 210 then 219 then 217 and 212. My guess is the fan comes on at 219. Now 219 may seem hot but it isn't. My Valkyrie would very often run at that temp and my Road King was near 230 a lot of the time.
Install was easy, remove the top radiator hose (requires draining the coolant) mark for the connector and cut out about 5/8" of hose. Install connector in each piece of hose (remembering to put the hose clamps on first) and reinstall the hose without tightening the clamps. Get everything lined up and tighten all 4 clamps.
There is plenty of wire from the sending unit to the gauge so then route the wire up under the tank to the top of the triple tree. If you have a faired model you can likely find several places to mount it. The sending unit comes with double face tape for a surface mount but that seemed a problem to me to get to the back of the unit if you ever need to (change battery, set calibration) so I went a different way. I screwed it to a small piece of 90* aluminum and then double face taped that to the dash as seen in the pic. 3M makes some outside double face tape at Home Depot for 5 or 6 bucks-it is awesome.
So now I know if I see above 219 for any length of time, I should probably check it out.
P1010619.jpgP1010616.jpgP1010617.jpg
Last thread I started was pirated by jfc at the other place-wonder if this will get there too?
 
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randy1149

New member
Nice find dave. From what I find the specs for the thermostat opens at (176 - 183)º, the fan kicks in at 220º. And your gauge is spot on.
 
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ofdave

Member
@randy
I knew about the thermostat but not the fan, good to know my "scientific study" has basis in fact
am now looking for a flux capacitor to add
 

randy1149

New member
A flux capacitor is just an adjunct to an existing thermal couple to prevent superfluous infrared radiation from extended beyond the Higgs Bosons expected life expectancy of .04 micro seconds.

I hope that clears it up for everyone.
 

randy1149

New member
Well well well... seems those "other guys" came around and copied the "flux capacitor" theory and posted it HERE in their forum by JH700CTX... that's called negligent plagiarism. Shame on you!
 
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ofdave

Member
Thought I'd bring this back.
Over on the other forum a guy just posted his install of this exact same gauge and the exact same location of the sending unit in the radiator hose-what a coincidence.
No mention of seeing the install explained here.
His average temps are much higher than what I run.
Either he rides slow in traffic or he may not have gotten the radiator full.
He consistently runs 212+ and I consistently run 182+. A big difference.
Anyway, this gauge install was a good thing for me. Only because I'm kind of nerdy and I like to see what's going on.
 
Only because I'm kind of nerdy and I like to see what's going on.

Do people think that is a bad thing? :) Actually, I'm aware of people who do at least think it is, if not bad, at least incomprehensible.

FWIW, the Honda radiator is pretty much identical in size to that of a first gen SV650 which puts out 30-40% more power so there should be plenty of excess capacity on the Honda. However, Honda in their wisdom has done a poor job of mounting it. Air needs to be able to get out of the back as well as into the front, and the frame/engine clogs up that space behind.

On the faired versions there are shrouds to direct air into the radiator which is good, but I guess they decided they'd look odd on the naked versions so they lack that bit of help.

If a good inlet/exhaust duct system can be used to take air to and from the radiator the size of the radiator can often be reduced pretty significantly. It can be difficult to find space for that ducting on a motorcycle, though many of them could at least have inlet ducting that forced air to go into the core and do some work instead of going around the sides.

It would be interesting to see if a faired CTX tended to run slightly cooler because of the shrouds.

cheers,
Michael
 

ofdave

Member
@michael
Mine is a naked one. It has side caps on the radiator, maybe not as big as the faired version, but there never the less.
I ran without the radiator side end pieces for a month or so when I first installed the gauge.
After reinstalling the end pieces, I noticed no real change in engine temps-maybe a couple degrees but I attribute that to warming weather-up from the low 70's to near 80.
The space behind the radiator, while seemingly small, does, not to me, appear to be appreciably less than many bikes. The FZ10, S1000RR, and others have similar limited space.
I like the gauge and I like having a voltmeter and I like installing a tach on every bike I ever owned that did not come with one.
It's enjoyable to me to add stuff and tinker rather than ride and repair as on some other bikes I've had.

Air does flow pretty well through the radiator as evidenced by the warmth felt on my shins at some speeds.
 
That's interesting to hear. I tend to do a lot of tinkering and occasionally my bikes will get back together and be rideable. And then I take them apart again to do something else. :)

Bikes have a problem of not being very large vehicles, and there are a lot of compromises that get made to get all the pieces on. With a conventional design it is probably a lot easier for the manufacturers to spec an overly-large radiator than it is to provide good intake/exhaust ducting to them. The intake duct should slowly expand from the air inlet to slow the velocity/up the pressure of the air before it gets to the core, make sure that all of the air then goes through the core instead of around it, and then the exhaust duct should converge to speed the warmed air back up before dumping it into a low pressure zone. The Britten and Tularis racers tried to achieve this by mounting the radiator nearly horizontal under the seat, though they didn't use exhaust ducting. But the intake side is the more important as it the air has already done its work after it gets through the core.

cheers,
Michael
 

MJC

Super Moderator
I like the idea of a temp gauge but hate that Amazon said " Currently unavailable.
We don't know when or if this item will be back in stock."
 

randy1149

New member
The capacity of the engines water jackets also affects the cooling efficiency. The more coolant you can circulate thru the engine the cooler it will run. Also the type of coolant... oddly plain water is more efficient than ethylene glycol but lower boiling point. Engine cooling is science in and of itself.
 
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I remember the guy who did my RR engines porting the water manifold on a 900 Ninja race engine. The engine was having some heating issues and he hooked the manifold to a water supply and ground away inside it until all the streams of water coming from it were of equal length (some ports didn't flow much at all). It didn't make a big difference, but every bit of improvement was useful.
 

randy1149

New member
Thought I'd bring this back.
Over on the other forum a guy just posted his install of this exact same gauge and the exact same location of the sending unit in the radiator hose-what a coincidence.
No mention of seeing the install explained here.
His average temps are much higher than what I run.
Either he rides slow in traffic or he may not have gotten the radiator full.
He consistently runs 212+ and I consistently run 182+. A big difference.
Anyway, this gauge install was a good thing for me. Only because I'm kind of nerdy and I like to see what's going on.

No water cooled motorcycle runs normally at 212+. That bike has got the same 180 thermostat as we do. Something is definitely wrong. If he posted here he would know that!
 
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