Last time the hose I could see was the CVT intake. Share card said 96°. CSV said the bay hit 163° on a channel I’d named Ambient. Next tip was supposed to go in the hose that leaves the clutch.

Saturday I put it there. The belt died on the way home. The log has a pretty spike. I already knew it was coming.. I heard it.

The Tip

ThermoPro on the bay plastic, 77 / 72 / 68 before we rolled. Jack 2 (blue) into the machine, tip above the slotted housing next to the quilted heat shield. Outlet air, not cabin. Names on the ride: Engine bay / Clutch / Ambient.

ThermoPro TP25 in the RZR engine bay before the Saturday ride, three tips live, jack 4 empty

ThermoPro tip at the clutch outlet, quilted heat shield on the left

The Ride

Out of Four Corners, south on River Road, all the way down Axtell / Anceney to Amsterdam, backroads back to pavement. Forty-five minutes. Then 84, last climb into Four Corners from the west, before Cottonwood. 65+ up a long hill. That’s where it gave.

GPS trace: Four Corners, River Road, Axtell / Anceney, Amsterdam, back

utvtron history: 58 min, 36.6 mi, Clutch 164°F peak, 54 impacts

58 minutes, 36.6 miles, 65 mph peak, 54 impacts. Clutch 164° max, 127° avg. Bay 102°. Ambient 89°. Headline follows the hot probe this time, so the card isn’t lying.

Cruise on the loop was 115–134°. Last six minutes are the hill: 126°, 140°, 151°, 164° at 55:56. Engine was fine. I could hear the belt shredding. That’s also the 65 on the card.

The app did what it’s supposed to do. Session held, GPS held, a BLE drop in the first five minutes didn’t kill the ride. None of that told me the belt was about to go. I heard it.

What Came Apart

A CVT belt has cogs on both faces and a tensile core through the middle. The core went. Outer cogs started peeling. That fluff in the tunnel is the core, blown into fiber. Same stuff packed the output duct.. the hose the tip was sitting in.

Shredded belt packed around the probe braid in the tunnel

I pulled the fiber out of the outlet and drove it home at 50. Didn’t walk. Wasn’t limping. It was already cooked.

Broken CVT belt fragment over the RZR center console

2017 RZR 4 900 in the yard after the ride

The belt was nine years old. The machine lives outside in Montana.. twenty below, then a hundred. Timebomb. Expected. Saturday it went off. 164° in dump air is not a prediction. It’s the funeral.

I’m not doing that loop again to “see if a new belt looks different.” I’m putting a new belt in so I can drive the thing. utvtron is a ride logger. It is not a crystal ball.

Live: utvtron.vercel.app