Thread: Lost the PTO on the 780
07-14-2008, 06:30 PM #1
Lost the PTO on the 780
I'd been riding for about 2 hours when the ski died. Fired right back up but wouldn't idle. We headed back to the ramp (3-4 miles) and I was down 100 rpm.
I pulled the plugs, they looked good but the PTO has a tint of silver/ash color to it. Redneck compression test (thumb over hole) told me it was low on the PTO.
A little background...topend .50 OS WSM rebuild about 28 hours ago. Carbs were cleaned and rejetted for good wash,new fuel lines,filters,selector,sending unit,etc. Case passed leak check.
I expected to find a holed piston but instead found this. There's small pieces embedded in the head. The cylinder walls are smooth, the marks in the picture are undetectable with your fingernail and mostly oil streaks. The piece embedded in the piston near the exhaust port is more squared off the round. The piston has no detectable up and down motion when at TDC.
I'm thinking crank seal failed and leaned it out but what is the debris?
07-15-2008, 05:34 PM #2
07-15-2008, 05:51 PM #3
- Join Date
- Sep 2006
My guess is that you have a rod pin, thrust washer gone or blued.
It also could have been a circlip and that it went out the exhaust. thats kind of what the dent above the exhaust port shows
Crank seals just dont FAIL. They have a reason for it and I dont see that anywhere on your piston. Did the piston seize in the bore?? You pics dont show the side of the cylinders
07-15-2008, 06:13 PM #4
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By addicted in forum 4-Tec PerformanceReplies: 20Last Post: 11-15-2011, 02:14 PM
By Piranha Performance in forum 2-Stroke PerformanceReplies: 0Last Post: 09-14-2008, 10:13 AM
By Feral in forum Polaris Open DiscussionReplies: 32Last Post: 07-06-2008, 11:57 PM
By JGringo in forum Polaris PWC PerformanceReplies: 16Last Post: 08-22-2007, 11:27 PM
By rapidacceleration in forum 4-Tec PerformanceReplies: 3Last Post: 02-25-2006, 11:07 AM