Sounds to me like there is a whole lotta extra work invovled trying to make an aftermarket gauge fit and work when there is a gauge already to go from the MoCo. I have the MoCo installed on mine and there wasn't any soldering or rerouting of wires or replacing the internal light. I did have to buy an adapter, which I did get at Napa.The adapter is a 3/8 NPT M x 1/8 NPT F, Napa #3220 x 6 x 2. I installed it in the pan for a year, then I decided to install it in the oil line per the MoCo instructions. Are you going for looks? I think the MoCo gauges look great and are an exact match to what I already had. Function and accuracy? It's all relevent. Your temp readings are not going to match the guy next to you. It is just a gauge, something for you to reference the running temps of your scoot. Just wondering why you wanna jump thru hoops for this mod. Don't get me wrong, I am not knocking the McEwen gauge.

 

My main reason was the thread in which they described the gap at the bottom of the HD gauge and the halo lighting effect. I don't have any first hand knowledge of this problem, but thought if there was going to be a possibility of a visual difference in gauges why not try the alternate and see how it looks/works. I don't think I'll have much to worry about as far as extra work as I will be routing the wires under the tank and therefor shouldn't run into the problem of the wires being too short. Changing the light bulb shouldn't bee too difficult and so far seems less of a pain than having to go to NAPA for the adapter that is included with the McEwen gauge.

Anyone know if the HD bulb from the Air Temp Gauge will work in the McEwen Oil Temp gauge? If so, I won't even have to leave the house when the gauge gets here...have everything I need already.

 

I moved the voltmeter and installed the HD oil temp gauge in its slot; the voltmeter is where the air temp gauge would be on a civilian EG, but my police model didn't have one. If I was doing this again, I'd put the oil pressure gauge above the oil temp since I'm more concerned about oil pressure than temperature.

Good luck with your project.

 

I am about to do the same project but with the HD gauge. Here is the link with the adapter type and even some pictures.
https://www.hdforums.com/forum/touri...-question.html

 

I installed the HD gauge which is different, but you should only need to run one wire under the tank (sender). Remove the rear tank bolt and prop it up an inch or so, then use a straightened coathanger wire to route the wire under the tank. It is a tight fit, a bit easier on the right side on my '07. I'm sure the McEwen instructions are good, but use the old ATG harness for power and ground for the gauge and light. The sender grounds to the pan on McEwan (separate wire on HD), so don't use Teflon tape on the sender or adapter. It's not necessary anyway. On my '07 the orange wire on the ATG harness is 12V (switched) and the black wire is ground.

 

I never notice this even though it is present, and I never even knew it existed until I read about it on this forum. After having it installed for two years I had to go out and check to be sure. I still don't notice it when I ride, day or night, and for me it's a non-issue.

 

In anticipation of recieving my new oil temp gauge...and rain for today and tomorrow...I just swapped the Volt Gauge into the old Ambient Temp Gauge spot.

I wasn't sure if I also needed to swap the wires to the other side...so I consulted the trusty Electrical Diagnostic Manual and low and behold they tap into the same wires and connectors. The only difference is that the Ambient Temp Gauge harness has one extra wire for the sensor. Since the mating terminal on the Volt Gauge is not present I didn't have to do any modifications to the harness to get it working. Just plugged the Ambient Temp harness into the Volt Gauge and it works like a charm.

Now about that hole in my dash....where's the UPS guy?

 

I put mine in place of the air temp gauge, little tight but had not problems. I like both my oil gauges on the bottom, makes it ez to read.

 

Finally got my McEwen Gauge yesterday and installed it. Here's the write up.

Everything you need to install the gauge is in the box. It comes with gauge, new mounting brackets, wire harness adapter, sending unit, oil pan adapter, and 1 long wire for sending unit.

I chose to move the volt meter to the ambient temp gauge spot and install the oil temp gauge where the volt meter was. This position allows easy access when installing.

Visually, the gauge matches the HD gauges really well. The only difference is the small script at the bottom says Roger McEwen Co instead of Harley Davidson.

I also figured out the issue some other guys were having with the needle resting to the right on the gauge. At first I plugged the wires in the way the directions said to and the gauge immediately pegged to the right until I turned the ignition on then it zeroed out. The instructions said to plug the 2 spade connectors into 2 spots on the 3 wire HD harness. I decided to see what would happen if I swapped the wires to the HD 2 wire harness. As soon as I plugged the spades into the 2 wire harness the gauge rested left instead of to the right. I left it that way and finished the install. Worked fine all day today and rested to the left like it should.

The sending unit install went much the same as everyone said. I had everything ready before pulling the oil pan plug and only lost about 2 ounces of oil into my catch pan.

Once the sending unit was installed I routed the sending unit wire behind the transmission, up under the seat in front of the battery, under the tank, and into the fairing. Man whoever said the wire was short....you were correct. With my routing I had no room to spare at all. I believe I took the shortest route possible to the gauge while still hiding the entire length of wire and I used every last inch of the wire. The last step was the crimp a spade connector to the sending unit wire and hook it into the gauge.

The sending unit wire, once it was installed and zip tied in various places, has plenty of slack to not cause any issues. But, make sure not to goof up because you will need every inch of it.

I rode a little over 300 miles today and the gauge worked very well. Originally, the only reason I bought this gauge was because of a flaw that was identified in another thread with the HD gauge. Well, I have identified 3 flaws with this gauge...

1) when installed, there is about a 1/8 inch hole directly over top of the gauge in which you can see directly into the fairing. I guess the mounting cup for the factory gauge used to rest in a notch that is not filled with the McEwen gauge. Easily corrected with black electrical tape on the inside over the top half of the gauge. Not noticeable at all with the fairing installed and the tape in place. I am wondering if it will turn out to be a dirt collection point though...

2) Sending unit wire length is to close for comfort. I think if you choose to mount it on the bottom row, either in the ambient temp spot of in the oil pressure spot you would have a few inches to spare though. It worked fine for me though and I expect no issues.

3) At night the backlighting is not as bright with this gauge as the rest of the gauges. The color is right...just not as bright. I may remove the fairing here soon and see if I can either use the bulb from the stock ambient temp gauge or order a new light as suggested above.

Seeing as I ordered this gauge because of differences in appearance from the HD gauge I would have to give it a thumbs down....only because of the hole and the backlighting. But the gauge works and I will not be changing it out. If I was ordering today, I would have gone with the HD gauge. JMHO

 

Just to add a couple more notes...

1) I've been told the HD gauge also has the hole over the top. The stock black plastic gauge mounting ring uses a notch in the inner fairing that is not used with the oil gauge install. You can either modify the plastic mounting ring and use it or use black electical tape or some other method of covering the hole.

2) Noticed this morning while ridiing in to work that the Oil Gauge fogged up pretty bad. The rest of my gauges have never fogged up...but not so lucky with the oil temp gauge.