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Discussion Starter · #1 ·
I just replaced a stator on my 97 Powder Extreme. I finally got it running and a buddy and I started up the mountain. Two miles into the ride the engine blew up. The crankcase (cylinder 3 - clutch side) blew out towards the front of the sled destroying the mounting bracket with it. It went with a loud bang and a lot of smoke. We towed it back to the trailer and the day was over (I forgot to gas up the spare sled that was on the trailer). When I got it back to the garage and pulled it out, I found that the break went all the way from the front to the bottom when the bolts are at that hold the case together.

The engine case can't be saved. I think that I will buy a used engine. The sled had the ZRT600 with the Black Magic 700 big bore. I don't really want go back to a 600 but I'm thinking about putting in the ZRT800. How much would I have to change out? Has anybody done this? I know that the exhaust is different. How about the electrical for the stator and sensor? The cooling hoses? If anybody knows of a parts sled in the SD, WY, CO, MT, or ID area, please let me know. I have been reading through previous topics and wasn't seeing quite what I was looking for.

The big bore was done before I bought it. The work was done in CO. I've been searching for the website for the Black Magic kit and can't find one. Anybody happen to have it?

Here are some pictures of the damage. One is from the front of the motor and the other is looking at the cylinder without the head. The piston is melted. Any ideas what caused it to blow? The rod is broke and the rod is probably what punched out the crank case.

[attachment=62983:engine_block.JPG] [attachment=62982:jug.JPG]
 

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Sorry to see your engine that way. Kind of gives me the shivers as I just rebuilt my 97 Powder Extreme engine but I went stock on it.

As for swapping in an 800, I have been told by two different sources that it is an easy swap, just have to buy a longer jackshaft and of course the carbs have to be changed out as the 800 runs 38mm carbs.

On Ebay there are some engines for sale right now along with a set of carbs for an 800 which are going cheap.

One question for you, do you still run the MAC or did you remove it? I removed mine as the guy who had it before me kept melting the mag side piston.
 

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Discussion Starter · #4 ·
<div class='quotetop'>QUOTE (JohnAB @ Feb 7 2007, 11:45 AM) <{POST_SNAPBACK}></div>
Sorry to see your engine that way. Kind of gives me the shivers as I just rebuilt my 97 Powder Extreme engine but I went stock on it.

As for swapping in an 800, I have been told by two different sources that it is an easy swap, just have to buy a longer jackshaft and of course the carbs have to be changed out as the 800 runs 38mm carbs.

On Ebay there are some engines for sale right now along with a set of carbs for an 800 which are going cheap.

One question for you, do you still run the MAC or did you remove it? I removed mine as the guy who had it before me kept melting the mag side piston.[/b]
I think that when you refer to the MAC your talking about the Altitude Compensater. It was unhooked when I bought it. From the reading that I've done, if it was still hooked up, I would have disconnected it anyway.
 

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Discussion Starter · #5 ·
Looking on Ebay, I found a lower end for a 2001 600. Will the 01 crank case work for my 97? How about dropping an entire 01 in? Will it fit or is the 2000 as new as I can go?
 

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I seen it happen many times, How many of you guys have taken out these 600 pistons that the intake and exhaust side piston skirts where cracked upon removal.

You lost a piston skirt that fell down in the front of the case and as the crank went around and there was no room for it as the skirt was in the way and it blew the front part of the case out to complete the rotation.
I have the same engine in my garage that looks just like yours, but on the mag side.

When you take the motor apart, I will bet you a beer that the other two pistons have cracked skirts.
 

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Discussion Starter · #7 ·
I read at the ZRT topic "More on stators" that Kev had a rebuilt stator from RM Stator that blew the exhaust off of the PTO cylinder. This is the same company that rebuilt my stator and the same cyclinder that went. I will have to pull the stator and look at it. Maybe it's more than a coinsidence.
 

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<div class='quotetop'>QUOTE (snow800 @ Feb 7 2007, 08:50 PM) <{POST_SNAPBACK}></div>
I seen it happen many times, How many of you guys have taken out these 600 pistons that the intake and exhaust side piston skirts where cracked upon removal.

You lost a piston skirt that fell down in the front of the case and as the crank went around and there was no room for it as the skirt was in the way and it blew the front part of the case out to complete the rotation.
I have the same engine in my garage that looks just like yours, but on the mag side.

When you take the motor apart, I will bet you a beer that the other two pistons have cracked skirts.[/b]

Wow, exactly right for my 98 ZRT 600. But the crank went and took out the mag cylinder. I was lucky that the block was OK. Upon removal of the other two cylinders bingo !! cracked skirts.
What causes this ?
Is it something common for ZRT600's ?
SDOG
 

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<div class='quotetop'>QUOTE (SDOG ZRT 600 @ Feb 8 2007, 01:52 PM) <{POST_SNAPBACK}></div>
<div class='quotetop'>QUOTE (snow800 @ Feb 7 2007, 08:50 PM) <{POST_SNAPBACK}>
I seen it happen many times, How many of you guys have taken out these 600 pistons that the intake and exhaust side piston skirts where cracked upon removal.

You lost a piston skirt that fell down in the front of the case and as the crank went around and there was no room for it as the skirt was in the way and it blew the front part of the case out to complete the rotation.
I have the same engine in my garage that looks just like yours, but on the mag side.

When you take the motor apart, I will bet you a beer that the other two pistons have cracked skirts.[/b]

Wow, exactly right for my 98 ZRT 600. But the crank went and took out the mag cylinder. I was lucky that the block was OK. Upon removal of the other two cylinders bingo !! cracked skirts.
What causes this ?
Is it something common for ZRT600's ?
SDOG
[/b][/quote]



It is very common on these engines, I can't tell you how many of these motors that I have fixed that had cracked pistons.
The pistons need to be replaced every 2500 miles, I never put Cat pistons back in them.
I have had very good luck with SPI or Wiseco pistons's in this engine
 

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<div class='quotetop'>QUOTE (sdle101 @ Feb 7 2007, 11:22 PM) <{POST_SNAPBACK}></div>
I read at the ZRT topic "More on stators" that Kev had a rebuilt stator from RM Stator that blew the exhaust off of the PTO cylinder. This is the same company that rebuilt my stator and the same cyclinder that went. I will have to pull the stator and look at it. Maybe it's more than a coinsidence.[/b]
I'd say more likely a coincidence. Backfiring, I'm sure, isn't good for an engine but piston skirts cracking would be a more likely scenario.
 

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I pulled my 1997 600 zrt apart at 5000 miles and found the centre piston had a crack down the centre on the exhaust side.This was the pipe that was always red when running hard in deep snow about 0 degrees celcius.I ported and replaced all pistons and ran it up to 12000 miles and pulled it apart again. No issues this time .I replaced the wrist pin and bearing on each piston and put it back together with new seals and gaskets.Not sure how many more miles it ran as i sold it the following season.I also ran all Castrol oil at 150 miles /litre.I was warned about the pistons so I guess there was an issue with some pistons.They are an awesome engine.
 

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Discussion Starter · #13 ·
Prior to this, I hadn't thought about the pistons being bad. The sled has 1900 miles and less than 800 on the Black Magic Big Bore kit. I checked the other pistons and everything looks good with them. I'm taking the crank and cyclinder to a guy in town to see if they are salvagable for a rebuild. I'm not very optomistic about the cyclinder though.
 

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Could the motor in my 2000 TT have the same problem...cracked piston skirts????

I have 2000 miles on the motor now. Should I tear this engine down now and check them or did they get the problem corrected by this model year?

Thank goodness for forums like this. Pistons are cheap if they dont blow your engine up first! I would never have known there was even a problem!
 

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Discussion Starter · #15 ·
I'm slowly getting things taken apart. The other two cyclinders look good. I can't find any cracks or signs of weak points. I found the other half of the rod (the end that connects to the piston pin). It looks like it had been bent to the breaking point.

Trying to pull the clutch off but things aren't lined up quite right inside. It took over 20 minutes to get the bolt out. Got tired of trying to get the clutch off and will try again tomorrow when I'm fresh.

For financial reasons, I think that I will stick with the 600 motor. Still looking for one. May have to wait for the tax return first.
 

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Discussion Starter · #16 ·
Had the cylinder looked and lower engine looked at today. It looks like the problem may not have been a piston problem. Something caused the cylinder to run lean and everything melted until it gave out and that was when the @#$% hit the fan.
 

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Discussion Starter · #17 ·
Well, I have found a replacement motor. I don't want the same thing to happen again. Can anyone help and offer an opinion as to why the engine blew.

The sled was running at about 7k and then jump to 9k. The engine didn't sound like it wound up, though. It would then return to 7k and jump again to 9k. It did this a few times. I can tell that the cylinder was dry. Since the other two cylinders were wet, I'm assuming that the oil pump was good. There was oil in all three tubes leading from the pump. I haven't checked the metal inlet from the tube to the engine.

How about the primary? How can I check to see if it was opening up correctly?
 

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It may have had an air leak, which may have been at the PTO crank seal, or at the carb flange. With the big bore kit the pistons were likely Wiseco pistons. You could put your 700 kit on the new engine, but you'll need to send that cylinder out for replating. Millennium Technologies should look after that for about $200 US. The only thing you can do is to check everything over as closely as you can and check it over on a regular basis. Rubber seals and flanges can fail as they age, so if you don't catch it first, you find it when the engine goes down.
 
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