I bought a basket case 86 elite 250 awhile back. Previous owner had tried to put in a new exhaust valve to fix low compression, but still only got 60psi...I figured out that he timed the cam gear wrong, now it has 140psi.

I cleaned the carb tonight and tried it on the road for a very brief go...at about 15-20mph there was a large POP sound...I thought it was from the rusted out muffler but decided to park it since it was already late and I didn't want to wake neighbors.

But after I parked it and was checking for any leaks, I see that the wire that had been on the temp sensor was dangling and the metal end was missing...when I looked for the prob it had been on, well...see the pics.

How the heck did this happen? I'm not familiar with liquid cooled engines, and I have all the hoses hooked up the way the previous owner did.

I assumed that was a temp sensor since it kinda looks like a thermostat housing.

Any ideas of what to check? I diagrams of how the hoses all around the carb should be routed? I'm thinking the only way for it to blow off that sensor was for something to be routed incorrectly.

 

That is very odd. That is the temp sensor. And it looks like it had pressure build up and blow out the sensor bung. But it doesn’t appear to be leaking coolant. I’d try a new sensor and make sure it’s wired correctly. I would try grounding that green wire that it was attached to with the ignition on and see if the temp gauge goes all the way to hot. Only do it for a few seconds to confirm it’s the correct wire and not damage the gauge. That wire will follow the wires from the autobystarter and plug in near the voltage regulator I can take picture of the carb and hose routing if needed.