Last time I said the next ride was the duct. Sunday afternoon I took it.. 2017 RZR 4 900, three ThermoPro tips this time. The app handed back a share card that looked done.
96° max, 18 minutes, 9 miles. Green line flat, blue line doing all the work. I almost posted that and called it a day.
Then I opened the CSV.
The Hose I Could See
The clutch housing is in the left-rear wheel well, and a fat J-shaped hose clamps onto the round cover. That’s the hose I could see, so that’s where a tip went. One stayed in the cabin. One went in the engine bay, since that’s the only place that got hot last time.
In the app I labeled the first two jacks Belt and Ambient, and the third fell through as “Probe 3.”
What the CSV Said
708 rows, a reading every second and a half. Bluetooth held, the screen stayed awake, no timestamp pileup like the first ride.
“Belt” sat around 90°. Probe 3 sat around 90°. “Ambient” started at 106° and hit 163° fifteen minutes in. The card only showed the first probe, so the headline was 96° while the actual heat was on the channel I’d named Ambient. I had the plugs backwards.
That Hose Is the Intake
The J-tube is the CVT intake.. it pulls cool air in. A tip in there is just going to read cabin air, which is exactly what it did. The clutches are further inboard, not behind that rubber.
And on this generation there’s no clutch exhaust grill. Polaris dumps the hot air right into the engine bay, over the trans, at the block and header. So the bay probe is a mix of engine heat and whatever the clutch was blowing out. Still not a belt reading.
I wasn’t going to build GPS or multiple probes this early. Built them anyway, and they paid off.. three lines on one chart is what made the mixup obvious.
Next tip goes in the hose that leaves the clutch, and this time the names match the plugs.
Live: utvtron.vercel.app.. Chrome on Android.
Update, Aug 15: I got the tip in that hose. Then the belt came apart.