So a couple weekends ago I went for my last ride of the season and it ended with a poof of smoke and bit of flames.

My sled is a 97 Powder Extreme 600 (basically a ZRT 600 with slightly different carbs, 6000miles on orig engine, 900miles since last top end rebuild). I was doing some casual trail riding when it happened and it was about -15C outside. I got about 20 miles away from the cabin when I started to loose power. I was noticing it more and more coming out of corners. I would get on the the throttle and it just kind of bogged which was unusual for this sled. normal this sled runs great but on that day something went bad.

After i lost power, the idle started sounding very tame and when i turned it around and decided to head back to base... that's when it lost all power, leaned out hard in the middle cyl, pipes got way hot and started burning the underhood insulation. I jumped off the sled and was able to put out the flames before it got outa hand. It all happened so fast.

I waited a couple of weeks until I could tow it home and start taking it apart to find out what happened.

Viewers may find the following images graphic and distrubing, discretion is advised...

Pipes are off and look at this, the alum heat shield is burnt up.


Off came the the heads and what do we have here??? a big pile of yuck in the middle...



Middle piston is BAD, but on the service, maybe just maybe the other two pistons are ok??

Nope, not ok, they are scuffed too.





Cyls off and if you look at the middle one (left in the pic) it has chunks of it cracked off...toast.



So ny question to the other ZRT owners out there.... Is it worth fixing, what would you do?

I think i'm look at a hefty bill so far, here's my list as is...
1.) piston, ring kit (3)
2.) remove bottom ended, shaftm rods and bearings serviced
3.) One Cylinder
4.) One reed to replace the toasted on on middle cyl

Anything else i'm missing?

I'm debating repair vs. purchasing a low millage engine from... wherever.. another ZRT600.

I do like this sled and would like it fixed and ready for next year. Anyone have parts, engines or can point me in the right direction?

Wierd.. i tried to edit some typos in my original post but I cannot find the edit button.

Aused engine will likely be the cheapest and easiest to do. I just had one go bad as well and the middle cyl was the worst. In the bottom end where the retaining clip slips into the bearing and case the thin side of the case broke off and went up stairs and beat up the piston. The crank bearings feel good to turn but have alot of slop sideways, Im going to get the crank rebuilt and start fresh. Always lots of parts for these on ebay , a set of 3 cyl just sold for around 150. Split your bottom end and have a look , be interested in finding out what really happened to her.

i say engine but get a tcat 1000 instead fix up and upgrade

There's a zrt600 motor on rbay right now if you search zrt600 on ebay motors , I think it's on for another day and a half. It will cost you alot less than a rebuild if it's solid.

There is more side to side slop then i would like. The reason I'm not interested in tearing into the bottom end just yet is cause once I do I know I will have to send the crank in to have new bearing etc put in and that will add more expense. Plus the center rod appears to have a slight bend to it. i will tear into the engine deeper if I have to but i'm in the early stage of dealing with this problem right now.

My plan is to search local for a complete engine, if I can't find, then search ebay, if i can't find then collect parts to rebuild this one.



A Tcat would be awesome but for the type of riding I do a 600 is plenty. Now if I happen to come across a TCat engine cheaper than a 600 then that would sway me to go for this type of swap. I guess it depends what is available to me here in Manitoba. I would go to Ontario and pick something up if there was something good though.



hmm i wonder if that's one of the no reserve auctions I stumbled on. So far i've watched one engine pass by for around 600$ US plus 279$ shipping. by the time it gets to my door that will be well over a $1000. I'm hoping since the season is over here that I can find a cheaper deal (on a tight budget at the moment). Right now i'm trying to see what an average 600 engine sells for.



In my original post i forgot to ask... What do you think caused this?

From those i've talked to so far and based on the piston's scoring, all signs point to a cold seizure. Does that seem like that is the case? Any opinions on what else might cause this or if you think it looks like a classic case of cold seizure?

I would guess from the pictures that it was either severe overheat from you're coolant freezing in the cyls and not circulating, you can check the strength of the coolant to see if it was this, or lack of lubrication, no oil getting to the cyls. did you take the carbs apart yet? if so how did they look?

I took each carb apart and really focused on the middle carb. There wasn't a single spec of anything obstructing in the carbs, they look great.

The coolant I was a bit nervous about. I'm a bit of a noob with watercooled sleds (i used to own a fan cooled Polaris, ran like a top 8000 orig miles and still pulling strong. I noticed my resevoir would be at or near empty every ride so I topped it up with some pre mix stuff that I bought 9silver 4L jug from cdn tire). Is there a thermostat in this system? perhaps it wasn't functioning???

No oil had me very concerned too. On my last ride, when it blew up... I topped the gas tank up with regular fuel so it was a full tank. Then I topped up my oil resevoir right to the rim. Now when it blew up I had just under 3/4 of a tank of fuel and my oil consumption was only what was in the neck of the resevouir (maybe 250mls of oil TOPS). Does that sound right????? I think it should have used more oil than that. i did about 20 kms of riding. That doesn't seem right???

Lack of oil is something I REALLY want to know how to check for. I've read mixed things here. Sometimes pumps fail to open, other times they fail and restrict.

Can someone tell me how to trouble shoot an oil pump on this kind of sled?

Thanks!

Also when I took off the heads yesterday. it was -17 and the coolant was very liquidy. I wouldn't describe it as frozen or slushy in any way.

UPDATE

Now that I have a new used engine I'm going to take it in somewhere and have those coolant and oil seals replaced as a precaution. I'd also like to have the weeping hole enlarged. Then i'll install it back in and see If the sled can be brought back to life.

Before I started working on the new engine I thought i'd better get the old one completly out of the chassis so i can have an easier time accessing the magneto and clutch. These will have to be removed and transfered over to the new engine.

A shot of where i work on it. I've kept it on my trailer so it's easier to move it around.


A pic of the melted down engine finally out of the chassis. I labelled all the electrical and ground points.
Question: Is it hard to remove a magneto, any tips? Is it hard to remove the clutch, need special tools, any tips?


Empty engine bay.


Bulkhead damage from the heat. i'll make a plate, drill some holes and add some rivets to strengthen it up.


Burned insulation under the hood.
Question: Where to buy this stuff? Home Depot?


Exhaust pipes. The aluminum shields are burnt up pretty bad, irrepairable.
Question: Where do you buy this stuff from? I couldn't find a part number or numbers for it in Arctic Cat dealers websites???


Any answers to these questions would be a MAJOR help.

Thanks!

I would check "snowmobile exaust" on ebay I saw a set of 600 pipes, like new on there last week. Other than the oem material, you could use some aftermarket exhaust pipe wrap. Someone on here would know where to send you, or google "exhaust wrap". Wrap the pipes only where they were covered by the factory. On the hood I have used aluminum heat reflective tape from Home Depot on past sleds with success. You don't need the insulation if it's burnt too bad to keep.Hope this helps.

I would also clean and flush all of the carbs. empty the gas tand and put in fresh gas, and make sure the oil pump cable is adjusted correctly. pre mix you're first tank at 50/1. What I do is on the first startup of the new motor, Have a piece of bent hanger wire and reach down and pull the oil pump rod up to full on, it will smoke like a son of a b%**, but you know it will get the all important oul on the first startup.

I had the same problem with my 98 it was the left side not the middle.The dealer could not find the cause of the burn down.I also burnt the insulation and the hood.Cost me 800.00 to fix,needed everything on the left side.Rode the sled 300 miles that year.That was 2 years ago,it has not started since than.The winter after the fix could not even pull it over.I thought the moter was siezed.Amazing the engine turned over this year.It would not start though.Maybe changing the gas and plugs might help.

The carbs are all clean and no plug ups of any kind. They are ready for a reinstall.

Right now i'm at the stage where I have my old engine and my new engine on the bench. I need to swap the clutch and the mad over. I'm trying to find tools or buy the tools that i'll need to do this. I'll also need to remove the water pump and change out all those seals that I think caused the engine failure. Better safe than sorry.

When you change the waterpump, pack the end balanceshaft bearing up good with lithium grease.

it's hard to tell from the pic of the pipes. but is that a crack I see in it along the underside ?

no balance shaft on this engine... by the pic's it
looks like it ran lean or a cold seize... split the cases
ya need a puller for the mag... look over the bottom
end real good.. if bearings feel the least bit rough
the will need replacement=$$$$. a used engine is
probably best if the price and condition are right!
On any reinstall ck the oil lines and ck valve at the
bottom of cases.. I have seen those fail if you mix
the wrong type of oils together. failed in a closed
condition.. not the pump.

check out ksi enterprise in wisco. they usually have ues and new motors out of the box. bought a bran new motor for my zl for about 1000. when i really looked at it piston kit re worked cylinders ect... it added up to be about the same $$$$$. or theres always haydays!