Blown motor help please

[Snowshovel]

Well the day started off perfect, we started up mountain and by the time we got to the trail head there was 10 inches of fresh powder on the trail and more falling in buckets. About 5 miles in I was in the lead and as we started to go up an incline i gave my (new to me, bought used last week) 03 Mountain Viper more gas. The result was bogging and the sled dying... hmm i thought bad gas from last year? fouled plugs? improper jetting as the altitude increased? So after inspecting the plugs the center one looked like it was burning lean, hardly wet at all after running for at least 45 minutes. Swapped in new plugs, and tried to start it, the crank would not turn, i pulled on the rope and she would come out about 5 inches and stop dead.

Fearing i had somehow seized the engine up I pulled the clutch shroud off and tried turning the primary by hand. At first it seemed stiff but then gave way and was turning fine. After many attemps the sled would not start so i hooked up my snatch strap and towed her out using my sons 600 Mountain Max. Once we got back to the trailer, i figured wtf lets give it another go before we try to drag the sled up the ramp into the trailer. Couple pulls and she fired right up, but something didnt sound right. It was almost like a piston was knocking, and the engine was shuddering.

I gave her some gas got it 1/2 way up the ramp and heard the sickening sound of the center piston rock going through the bottom of the case. A mad dash after moving everything off the floor to avoid the coolant that was leaking everywhere we popped the hood open to survey the damage. First thing out of my buddy's mouth "Rob we got debri" you dont want to know the first thing out of mine. The center piston rod had come loose and popped a hole right in the bottom of the case. I just bought this sled 8 days ago, the guy i bought it from said it was awesome for him and other than some minor "kissed a tree" repair he had no issues. It had 7000 miles on it and after looking it over had no visable defects other than a minor oil leak.

I had all fluids full, I was using oil the reservoir had gone down some from where we started. Only maintenance i have done on it was clean the power valves yesterday, which after pulling the top end off looked fine. So no way the powervalves caused this, di i just get the $hitty end of the stick and it was me the engine happened to fail on? Those of you who have owned these sleds please weight in and give your opinions. I am attaching photos of the damage, and am looking for a new motor if anyone has one.

Also is there a way to test your oil pump with the motor tore apart? A way to energize it and watch it pump to ensure it is working before i get a nerw motor and do it all over again?

[KWB]

Viper I assume?

I don't know too much on the Viper Motor but check to see if oil cable came disengaged- it would be oiling at ~200:1 (idle mix) so you would show some use for the day but when making real power you are oiling at ~20:1.

[777]

7000 miles, it was just time.

[Yamahamod]

Originally Posted by 777

7000 miles, it was just time.

x2, Wow 7000.

[Get Lucky]

I woudl say lack of lube is $.02 I have seen several yamm's goover 10000 miles with no problem other then rings.

[m8magic]

you must have had added alot of fresh gas to last years i hope..??..check that center carb once the float bowl is of for debris in jets or torn carb boot

[Blownoutlaw]

all of the above,looks lein to me,you center cylinder always run hotter..so you either got it to hot ,, or the center carberator is plugged,pull the carb and inspect all the jets after removal,,like stated theirs probably crud in them..i always clean my carbs every year no matter how the sled runs just to make sure theirs no crud in the float bowls..Then i put 1/2 a can of seafoam in the tank and never had any issues.

[hurricane]

Looks like a broken ring. The Viper has wide exhaust ports and the rings will snag when they get worn too thin. They dont last forever.

[RedneckRidgeRider]

mine is blown too. 8000 miles on ams oil .We were racing full bore witch I dont do much ,no where to go that fast for long anyway around here except the lake. I need a cylinder . Got one???