Adding a Temperature Gauge to a 2001 Ski-Doo MXZ 800X
My 1995 Mach I 670 is as fast as most 700cc sleds today. The rotary valve Rotax twin in the Mach I is an incredible powerplant and runs with bigger sleds, but the chassis is really starting to show its age. On smooth groomed trails, it corners incredibly well and of course, on the lakes, it is a rocket. However, when the trail got rough or the ditches packed hard I found myself envying the sleds ahead of me soaking up the rough without taking such a physical beating. Therefore, I bought an MXZ to try, for the rougher stuff. The ride is incredible, especially when pushed hard. The more aggressive I ride it, the better it works.
One thing I miss from the Mach I, however, is the complete gauge package. With the Temperature gauge and electric fuel gauge, the rider could keep informed of the vital information with a quick glance at the dash. Riding on the hard pack I could watch the temperature slowly begin to edge up and every once in a while run through some powder or looser snow at the edge of the trail and see the results as the gauge moved back down into cooler temps. Warm-ups were not a mystery. It would take about four minutes on a warm day and six or more minutes on a sub-zero day to see the gauge begin to register the type of temperature I wanted before revving the engine. Even after a thorough warm-up, I noticed that as I headed down the trail, the temperature would fall off as the still cold coolant in the rails circulated faster with the higher revs. I really wanted to be able to monitor this critical engine information on the MXZ also. Therefore, I ordered up the temperature gauge kit from my local SKI-DOO dealer and added it to my MXZ for this season.
The kit comes with all the wiring and fasteners necessary and a new temperature sensor/sending unit. The factory-sending unit is an off-on type as required for the idiot light while a gauge requires the variable-resistance type. I went with the SKI-DOO kit because I wanted the gauge to match the other factory gauges, but an aftermarket gauge will do fine. You will just have to get the matching male electrical connector and sending unit. Ski-Doo has prewired the dash for the gauge and the kit comes with the matching male spade-lug connectors. The instructions included with the kit are reasonably detailed and presented no difficulty, but a few photos here and there can make it more interesting and perhaps induce you to add a gauge to your sled.
The sending unit on the 800 Rotax is just below and to the right of the coolant outlet fitting. You can see it here as the brass hex fitting directly below the coolant line hose clamp.
You must remove the airbox, the DPM unit, and the intake resonator (sometimes called a Boost Bottle). Take a note as to the hose and cable routing for reference. A quick sketch or photo will do nicely. With these items removed, there is easy access to the sending unit. Remove the wires from the sender, but leave them strapped to the plastic connector housing as shown in photo. When removing the sender be very careful of the limited clearance on the backside. Clearance is machined on the head, but if the wrench binds into this area while loosening or tightening, the sender can break very easily at the threads.
Apply a small dab of thread sealant and install the new sender. The instructions call for a torque of 53 in-lbs. However, there was insufficient clearance on my sled to get a socket on the hex. Therefore, I had to use an open end. Reconnect the wires to the new sender, there is no polarity concern, so as long as the male spade-lug blades are close to vertical it will go fine. You can now reassemble the airbox, DPM, and intake resonator. Double check hose and cable routing, airbox to carb clamps, and check the throttle and choke for binding, they must work freely.
Now you can remove the air intake plate from hood. The four brass colored screws are all that hold this on.
With the air intake plate removed, create clearance for the gauge. You must move any wires or cables that may interfere with the cutting of the gauge hole or installation of the gauge. You can see on my application, it was completely clear behind the gauge area on the left side of the dash.
Time to cut the hole. Be sure and accurately mark the center of the cutout area. The kit includes a template for the location. I carefully cut it out and placed it on the dash only to find it lined up with the factory Ski-Doo logo circle. Nevertheless, it still gives you a convenient method of finding the center-point of the cutout. A 2-1/2” hole-saw will provide the cleanest hole. However, a Dremel type tool or a keyhole saw could be employed to do the cutting, if you do not have a hole-saw. Just clean up the edges nicely and test-fit the gauge often. You want a snug fit that will not be prone to moisture getting past the gauge.
A rubber gasket slips over the gauge housing to help keep the snow and moisture on the outside of the dash. Slip this on and insert the gauge in the hole.
Slide the L shaped retaining clip over the screw studs and install the flat washer, lock washer and the nut. Finger tighten these and check the gauge face to ensure it is aligned correctly.
Now for the wiring, Ski-Doo has installed the wiring from the sender to the gauge for you, it is Zip-tied to the wire loom right beside the Speedo cable. Snip the tie and pull the wire connector end out in the open. Locate the male wire spade-lugs from the kit and crimp them securely onto the wires coming from the gauge. Two yellows wires are connected to a single male wire end spade-lug, one from the gauge and one from the light. They are pre-stripped and the length of strip is plenty for a secure crimp. Remember when crimping wires, the exposed end goes under the first set of crimp tangs while the second set is crimped over the insulation; this secures the wire from tension pulls. There are also two yellow/black wires (Yellow with a black stripe) they must be crimped to a single spade-lug also. The purple wire (in picture, green on instruction sheet) is single and is crimped to the last spade-lug. They can then be inserted into the plastic connector housing where they will snap in securely. You will also need to unhook the factory temp light wire and tie it out of the way. If left connected, the gauge will read incorrectly.
CAUTION: Once snapped into the plastic housing a special tool would be required to remove it. Not a common tool so make sure your crimp connections are secure before inserting the spade-lug into the plastic connector housing. From the front-side, as in picture, the yellow wires are the vertical spade spade-lug on the left, the yellow/black wires or the vertical spade spade-lug on the right, the purple wire will be the horizontal spade spade-lug above them.
Now connect your new connector end with the factory connector. They push together snugly. Use the zip-ties in the kit to route the wires away from areas where they may rub against the gauge housing or hood. The kit comes with two ties; after this photo I added two more to secure the wire loops shown, because the rubbed against the foam air intake retainer (seen behind wires in photo) when the air intake plate was reinstalled.
Replace the air intake plate on the hood and check that no wires or cables are pinched or kinked. Top off the coolant tank if necessary and fire up the motor. It was about 50◦ F when I fired up the 800 and I timed how long it took to get the gauge to move off cold. It took just over four minutes to get the reading in the photo. It seemed like a lot longer just standing there waiting and I am not sure I would have waited that long before heading out, especially if I was completely suited up and ready to ride. Generally, I will leave the gloves and helmet off and let it idle while putting them on back in the shop. I doubt it takes four minutes though.
The entire project took approximately three hours. That included taking photos and pulling the carb bowls off to clean too. I am very satisfied with the outcome. The factory kit is very complete and the gives the gauge that OEM look I wanted. I can now look forward to getting out on trails with the ability to monitor the critical warm-up and operating temperatures.
Submitted by MNSledder