Intruder Death Whistle

[no-h2o]

.... So me and some buddies are out on a vintage river run, and just as I hold it to the bar to whiz past a Polaris Colt, an AC Cheetah, and a Ski-Doo Citation, I start to hear this whistle noise. Looking back quickly thinking somebody is catching up, I begin to think vacuum leak, and let go of the throttle. Within a second or two of that, the engine instantly quits, and I come to a halt. The clutch side plug is insanely hot, and a pretty silver colour; ugh. I'm assuming I have just experienced the dreaded crank seal failure that I've heard about. The jetting was spot on last winter, and carbs nicely synchro'd. It pulls over fine, so I hope the cylinders are OK. I'll pull the engine out later this week & begin the tear down; any suggestions on where to find parts in Canada?
BTW, I'll never live down getting towed back by a machine with a leopard print seat ... LOL

[jimvw57]

Yup you got a melted piston. If it hasn't gone all the way through, you are lucky. Still need to tear it down and do a thorough clean up job.

[no-h2o]

Before & after pics. Break in run this weekend. Question about spark plugs: What is the difference between NGK BR9EYA (which was in it when purchased) and the BR9ES ?
Like anything else, all my buddies have different opinions, and some say the 9 is too cold of a plug & I should swithc to a 8 series plug.
Thoughts

[Interceptor398]

9 is what the book says.

[mswyka]

I run BR9EYA in all our sleds.  They run great and the split electrode seems to be less prone to fouling than the stock BR9ES plugs.  The side of the piston looks terrible.  Usually when we burn out a piston on a lean condition we both bore a hole in the crown just downwind of the plug and ruin the exhaust side of the piston.

[Checkmarks]

Look at that piston wash, unless you have new pistons that have not had time to carbon up.  Looks like a lean cylinder.  What does the other piston look like when you look down the hole with a light?  If one side looks like your photo and the other piston looks like it has a good wash plays a role in diagnosis.

With that PTO side toasted I would be first be checking the carburetors for the right jets and that they were clean first.  Second I would go after the carburetor flange looking for cracks and or air leak.

Last suspect the crank seals (in this case).  Always change the crank seals unless you know the somebody that put them in and >two years old.  Only because the crank seals on that side of the motor are bathed in oil on the far side via the gears that drive the oil pump and or the water pump.

Too hot of a spark plug would punch a hole through the piston (Br8es maybe).  The book says Br9es,  which ones do you think you should run?  Maybe go with your buddies suggestion he might know something the Kawasaki engineers overlooked.  X2 with mswyka.

Do you have the oil injection pump working for you?  Are you a premix gentleman?

[Lloyd (ljm)]

 that happened to me once ( hate that sound). Fan belt had broke and cooked the PTO piston.

 Now the first thing I do when I get a fan cooled sled is change the fan belt.

 Lloyd

[no-h2o]

It looks like a 4corner seizure; and the temp was -25 Celsius when it failed at WOT. Fan side looked good, but replaced both with Wiseco. Crank brgs all good & both cylinders fine. Oil injection system intact, and set up according to shop manual. After burning an entire tank of fuel following the break in procedure, I put fresh 91 octane in and did 80 miles yesterday on a vintage poker rally. I think I've got jetting issues. Starts & idles fine cold & hot, very slight hesitation / bog on accel up to 1/4 throttle then cleans up nicely as you continue to accelerate. There is a sweet spot just past half throttle where it seems to clean up & it goes like a bat out of hell hitting close to 50mph as long as you hold it there. Try and squeeze the throttle past that point & it slows down and bogs, like its suddenly too fat & the more you squeeze the worse it gets. Elevation here is 2200 feet; any suggestions on jetting sizes ??
Thanks

[Checkmarks]

Jetting,

Sounds like you are a slight rich at idle.  Lean in the needle and jet and then rich in the main numbers.

How is your carburetor set up now is the first big question before anybody can answer.  When you can answer that then a solution can be working in the correct direction.

My best guess is somebody dropped the needles to attempt compensation for jetting that is too rich.  This is likely the cause for your first seizure, too lean in the mid throttle.