Looks like many people have replaced the ambient temp gauge by an oil temp gauge on their EG Classic and Ultra. I wonder why I've never heard of people mounting an engine temp gauge instead of an oil temp gauge.
The EITMS is triggered by a sensor located in the front cylinder head, not in the oil pan, so wouldn't it make more sense to monitor the temperature of the engine?
What do you think?

 

Most people would not know what the readings of a CHT monitor would tell them. They understand oil temp. Since these engines are not liquid cooled, the oil is a good place to read averaged operating temp. CHT would be all over the place as you ride and accellerate and decelerate. CHT could alert you to eminent failure a few seconds sooner.

 

There are vendors, not Harley, who sell gauges for measuring cylinder head temperature so if you want one, buy one and install it. Back in the day, HD offered a cylinder head temp gauge and they show up on Ebay from time to time.

If you have a SERT, cylinder head temp is one of the values that you can capture so the ECM is "seeing" cylinder head temp.

Personally, I don't care what the absolute/accurate oil temp is, any more than I would care about the absolute/accurate cylinder head temp is. I have the oil temp guage to identify any abnormal increase which would suggest a problem, and would use cylinder head temp the same way.

If HD offered a cylinder head temp gauge that matched the spun aluminum gauges in my bike, I would have purchased it instead of the oil temp gauge.

 

I don't mean to start an argument but what's easier to understand with OT? Both show numbers, one being slightly lower than the other, that's all.
The ECM doesn't track OT but CHT. That's what the EITMS uses. Your OT gauge will show something like 240-250F in the oil pan when the rear cylinder shuts off and the shut-off is programmed to occur above 285F in the front cylinder head. I would assume that it'd be preferable to monitor this information over the oil temp, no?
As far as CHT being all over the place during acceleration and deceleration, see what your OP gauge does.
I think Harleypingman confirmed what I thought, which is, in the absence of a matching CHT gauge offered by Harley, people mount an OT gauge but if they had the option, most likely a CHT gauge would be installed. I don't have an OT installed so I'm still undecided. If I can find a close match CHT, I might go this route, but only if the wiring can completely concealed.

I didn't know Harley had one on earlier models. I learned something new today. I wonder why they stopped offering it.

Thanks guys.

 

I think it would be very informative to have a gage for OT and CHT.
Outside of being fun to watch the numbers go up and down, it might inform you of a problem you might otherwise miss.
Maybe you could learn and understand how an engine reacts to situations better, like, more or less throttle, up or down hill, summer vs. winter, auto-tuners.....
Using a cheep infrared temp gage for RC trucks, my front head is about 20* cooler than the rear normally. When riding in 40 - 45* weather with fabric lowers on my 08 standard, the front head temp is about 210* and the rear gets about 310*. So I think it would be cool to see temp for both heads.
Some people that use Nightriders Xied's claim their bikes run cooler.
A CHT gage might prove that.
Maybe if CHT was discused as much as OT people would understand CHT better.
Maybe a CHT gage would just freak people out.

 

I would like to know the CHT as well as OT, but I haven't found a CHT gauge at a reasonable price that I feel would last on an HD. I also don't have a place to mount another gauge. Since CHT should stay within the range of an OTG (350° in the case of the HD model), it would be nice to figure out how to translate the presumed 0-5V output of the J1850 port (to head temp sensor) to the OTG, but my engineering credentials aren't good enough to know where to start.

DynoJet knows the algorithm and a display is shown in their PC software, so it's not like it's a deep, dark secret held within the hallowed halls of the HD engineering dept. If it could be done we could connect an A-B switch to the gauge and toggle between OT and CHT. Wouldn't that be sweet!

 

I'm with Harleypingman on this one. I understand the value of a CHT gauge and an OT gauge. If someone made available a CHT gauge that was as easy to install as the OT gauge then the decision probably would be more of a coin toss because they both bring value to the party. I don't understand the desire to have a CHT gauge so I know when the cylinder head temp is approaching the EITMS cut off. Then again I don't see the necessity for an idiot light (not my term) to warn me when the fuel level is low. Seems a bit redundant to me.

 

The MOCO has offered accessary CHT and OT guages for their touring rigs in the past (early 80's I believe).
Many, many phone calls to the MOCO with grave concerns over the "peak" temps seen on these gauges during rides which included sitting in traffic and high ambient temps.

The MOCO fielded these calls by basically telling owners the peak numbers are not important so just enjoy their bikes and don't worry about the temp(s).

It was with great reluctance for the MOCO to come back and offer an accessary OT gauge for the touring bikes again....possibly due to aftermarket suppliers taking business from the MOCO.

I personally doubt they will offer a CHT gauge again because it will scare the crap out of most owners who do not know how air-cooled engine temp can and do grossly vary in temps as a "ride" goes on through differing conditions.
Just my $.02,
Bob

 

+1 Just notice (too many to read) the 100's of threads about how hot their Touring models run, and the numerous threads about cooling them off. Imagine if those same folks had a CHT gauge to really send them around the bend.

No way HD offers a CHT gauge with the lean AFR, EPA induced heat the bikes now have IMO.

If you want to know your CHT, buy an inexpensive laser thermometer and measure it at the base of the spark plug while parked, of course.

 

You want CHT guages? There are some nice dual needle ones available now. They are easy to wire in. The thermocouple line goes from the guage to a copper ring that the sparkplug clamps down. You only need to run wiring if you want to backlight it.
Here is one example, there are dozens at this supplier alone.
http://www.aircraftspruce.com/catalo...HT_gauges2.php

CHT was very important to me on the dyno when the OEM I worked for was developing their own FI system. It's important in the airplane as it is an indication of mixture and pretty damn important since you can vary the mixture with a ****. On a bike, not so much to me. Oil temp gives me a better general picture of temps.