Looks like the classic 800 stuck open oil pressure relief plunger. You likely had plenty of oil, just no pressure when the pressure relief device stuck open. Common failure mechanism on this engine.
In the end, we found that an exhaust valve stem seal had failed which allowed his oil to leak down and burn out. He had less than a half a quart left in the oil pan when we took it apart. Normally, the person following him would say "hey, man. You're burning oil" and we would know. But, in the rides leading up to this failure, he was always the caboose with nobody behind him. That being said, I've never seen a stuck oil pressure relief plunger, but I did some quick searching and see that it is pretty common as you said. I'm surprised that these machines don't have oil pressure sensors on them. With all they go through, that would save countless engines! This machine is my uncle's and he is planning to add an external oil pressure gauge, hoping to prevent a 3rd rebuild!
@@3DayWeekend An oil pressure gauge/sensor should be standard equipment on the 800s for sure. Interesting on the exhaust valve seals. The 800s I’ve had apart only had valve seals on the intake valves.
In the end, we found a leaking valve stem seal. It was letting the oil get down into the cylinder. During those 3 rides, he was always the "caboose" so nobody was behind him to say, "hey, you're burning oil!" New seals are in, and the oil level is holding strong. He still checks it before every ride though, just to be safe!
I am working on my brothers that he gave me and it is identical failure connecting rod failed locked up bent rod 90degrees knocked off a ear on the cylinder jug and everything lol it just didn’t snap the cam in two other than that identical
Thanks!
Thank you very much! I greatly appreciate that, and thanks for watching!
Looks like the classic 800 stuck open oil pressure relief plunger. You likely had plenty of oil, just no pressure when the pressure relief device stuck open. Common failure mechanism on this engine.
In the end, we found that an exhaust valve stem seal had failed which allowed his oil to leak down and burn out. He had less than a half a quart left in the oil pan when we took it apart. Normally, the person following him would say "hey, man. You're burning oil" and we would know. But, in the rides leading up to this failure, he was always the caboose with nobody behind him. That being said, I've never seen a stuck oil pressure relief plunger, but I did some quick searching and see that it is pretty common as you said. I'm surprised that these machines don't have oil pressure sensors on them. With all they go through, that would save countless engines! This machine is my uncle's and he is planning to add an external oil pressure gauge, hoping to prevent a 3rd rebuild!
@@3DayWeekend An oil pressure gauge/sensor should be standard equipment on the 800s for sure. Interesting on the exhaust valve seals. The 800s I’ve had apart only had valve seals on the intake valves.
So it was checked 3 rides earlier… where did the oil go? Did it smoke when it was running?
In the end, we found a leaking valve stem seal. It was letting the oil get down into the cylinder. During those 3 rides, he was always the "caboose" so nobody was behind him to say, "hey, you're burning oil!" New seals are in, and the oil level is holding strong. He still checks it before every ride though, just to be safe!
@@3DayWeekend Wow good to know! Thanks for the update.
I am working on my brothers that he gave me and it is identical failure connecting rod failed locked up bent rod 90degrees knocked off a ear on the cylinder jug and everything lol it just didn’t snap the cam in two other than that identical
Oh man! That's crazy! Hopefully you're able to fix it up and get it running again! Thanks for sharing and for watching!
Absolutely I enjoyed the video, keep up the great work 👍