Last time I said the next ride was the duct. Sunday afternoon I took it.. 2017 RZR 4 900, three ThermoPro tips. The app handed back a share card that looked finished.
96° max, 90° avg, 18 minutes, 9.0 miles, 3 impacts. Green line flat. Blue line doing all the work. I almost posted that and called it done.
Then I opened the CSV.
The Hose I Could See
Clutch housing is in the left-rear wheel well. 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, because that’s the only place that got hot last time.
Garage got the two-probe preset. Belt. Ambient. Jack 3 fell through to “Probe 3.”
What the CSV Said
708 rows, every ~1.5 seconds. BLE held. Wake lock held.. no timestamp pileup like the first ride.
Jack 1 (“Belt”): 88–96°, avg 90.5. Jack 3: 91–97°. They never really separate. Jack 2 (“Ambient”): 106° at the start, 163° at minute 15, avg 142.
The card’s 96 / 90 is jack 1 only. Max and avg follow the first probe. The heat was on the channel I’d named Ambient.
After staring at it: clutch and cabin stayed similar. The engine compartment got hot. Labels didn’t match the plugs. The chart was honest. The headline wasn’t.
That Hose Is Intake
The J-tube is the CVT intake. A tip through the wall is sitting in incoming cooling air, so it should track cabin ambient. That’s jacks 1 and 3. The clutches are inside the cover at the far end, inboard.. not behind the rubber.
On this generation there’s no clutch-exhaust grill. Polaris pumps hot air into the engine bay.. open duct off the inner housing, over the trans, at the block and header. So the bay probe is mixed air: header soak plus whatever the clutch outlet was dumping. Same neighborhood as the 142° I read off the ThermoPro screen in July. Still not a belt reading.
I said I wouldn’t build GPS and Garage until the loop proved out. Then I built them anyway. Sunday they earned some of it.. three series on one card made the mislabel obvious, and the CSV let me argue with the headline. Labels aren’t decoration.
Still Not a Belt Temp
Intake air next to cabin air means I measured the hose, not the clutch. Next tip goes in the outlet duct, before it dumps into the bay. Plugs matching Belt / Ambient / Engine bay.
Live: utvtron.vercel.app.. Chrome on Android.
More once the tip is in the hose that actually leaves the clutch.