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Discussion Starter · #1 ·
I've tried searching to see if anybody else has had this happen to them without much luck. The story goes that my brother (who is building an exo-cage for me) gave his daughter a 5 mile ride and when he got it back to his house it made a loud pop (obviously) and died. There was plenty of oil in it but this is what popped.


 

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King of crash!
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did a valve come lose? i see alot of damage to the top or is that from the broken ring lands.... it looks like something stoped the piston from going all the way up and thats how the skirt broke...or it siezed n the bore but looks more like something hit the top
 

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Discussion Starter · #3 ·
My brother lives about three hours away from me so I haven't seen it myself but he said that he could grab the rod and pull it up about a half inch and it doesn't move the crank. Whether that is the cause or the aftermath I couldn't tell you. The cylinder has two big gouges in it as well, presumably as a result, and I don't know about the valves. The head is marred but may be able to be fixed.
 

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My brother lives about three hours away from me so I haven't seen it myself but he said that he could grab the rod and pull it up about a half inch and it doesn't move the crank. Whether that is the cause or the aftermath I couldn't tell you. The cylinder has two big gouges in it as well, presumably as a result, and I don't know about the valves. The head is marred but may be able to be fixed.
Wow I would say the crank bearing failed first allowing the piston to travel further up than it was supposed to. Hitting a valve and possible the head and then busting the skirt off in the weird angle it was forced into. That looks rather expensive. Piston, Rod, Crank, Head, Valves, Cylinder.
 

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Discussion Starter · #5 ·
Yes it does look expensive (cringe)...I'm thinkin' I just as well do the big bore kit while I'm at it. Most of that stuff generally comes in a BBK doesn't it? Minus the crank and rods maybe. I think the valves might be okay...dunno yet though.
 

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Yes it does look expensive (cringe)...I'm thinkin' I just as well do the big bore kit while I'm at it. Most of that stuff generally comes in a BBK doesn't it? Minus the crank and rods maybe. I think the valves might be okay...dunno yet though.
I wish you the best, but if its anything like the grenades I have had the valves are toast. I hope you get lucky though. Not sure what comes in the big bores anymore. Been a long time since I put one in anything. But they didn't come with cylinders and I am not sure if Polaris uses the nickel plated cylinders or not. So if you have damage to the cylinder and I am certain you have you are going to need to address that issue. The kit might come with sleeves to push in though. I would have it checked very close for cracks in the cylinder.

There are others on here that have WAY more experience with Polaris engines than I do, so I would imagine they will lead you in the right direction.

Good luck let us know how it turns out.
 

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Discussion Starter · #7 ·
Yeah the cylinder is wasted too, it has two big gouges in it. I've only read a little about the BBKs and have seen "bolt on" which leads me to believe that a new jug comes with it but I don't know...getting ready to do a little more research on it. Anybody that does know about the BBKs is welcome to chime in at any time.
 

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Yeah the cylinder is wasted too, it has two big gouges in it. I've only read a little about the BBKs and have seen "bolt on" which leads me to believe that a new jug comes with it but I don't know...getting ready to do a little more research on it. Anybody that does know about the BBKs is welcome to chime in at any time.
You might look on ebay at used cylinders. I have seen them on there before. Or someone on here might have the stuff you need in the classified section on here? I used to build racing banshee motors and most of the BBK's I used did not come with jugs. There were companies that offered them but man they were expensive.
 

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the 840 BBK will come with pistons, rings , gaskets and a new cyl. It sounds like your gonna need a new crank too.
Call alen over at ricochet racing he will hook ya up.
 

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King of crash!
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most of the bb kits for the rzr come with a sleved cyl or a new cnc jug.. but some also have a cyl core yours might not pass for a good core....
 

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Discussion Starter · #11 ·
Yeah I was kinda figuring that I would have to pay the extra $$ without a core. Rebuild, unfortunately, is going to have to be on hold for a little while...a piece at a time kinda thing. So is the crank pressed together and not rebuildable or can I just replace the rod? Thank you guys for your input.
 

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I read somewhere on here that the stock ring gaps are too tight. You add heat, the ring expands to a point where it will stick. Iv seen a couple sbc 350 pistons that look like that. Something to think about...... and very probable........
 
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