Hey guys. What do you think happened.

[rminier]

http://www.dootalk.com/forums/topic/951545-piston-failure-analysis-guide/

Follow link to the bottom for pics...
This may help at least eliminate some possibilities.
Sorry to see this.....don't give up!

[Vader440]

This is why I got rid of my El Tigre's. These liquid cooled engines just seem to be more trouble than they're worth. As much as I like the look of the Invaders, I think I'll stick with the fan cooled Intruders. Just my two cents.

[chaddyg8]

This sled has been a Challenge  since I bought it! Lol!!! It was one of those good deals! At only 200 bucks. After a rebuild, new drive cog, 2 new used carbs and a lot of small parts it was running!! I still think it’s something I did or missed? When I was growing up my dad had a drifter which we loved! And I always wanted an invader....  i’m a little bummed now but it will run again!!

[Vader440]

Definitely hang in there! I just got tired of wrenching on the Tigre's.

[mswyka]

Like Winston Churchill said, never give up, never give up, never give up. But I will add that with these sleds the long way is the short way - and the best way to have them work satisfactorily is to do as thorough a job as possible.

Early on, because of their simplicity, I had a preference for the intruders. But as time passes I enjoy the invaders more and more. For many years my favorite was the 340, but again with the passing of time I have become more fond of our 440. I wish there was some magic to make them work the first time, however it always seems to be a series of little things. There may be a few frustrating moments, but you are on the right track. These times of frustration are just one more symptom of Mad Kaw Disease. If you look at the number of posts that I have made I will tell you that most were to ask advice about a problem I was having a hard time figuring out. Thank God the guys on this site are patient.  Oh, and somewhere on this site I had shared the story of our first Invader - "Free Snowmobile - $2,000."

[kawhead]

free sled...$2000  you got by cheap   

[kawhead]

bought a kitty kat for 800, needed new track and drivers and misc,300,....grand kids better like it

[mswyka]

bought a kitty kat for 800, needed new track and drivers and misc,300,....grand kids better like it

Well, with the grand kids, it is 50/50.  But I am sure grandpa will like it!

[kawhead]

lol  already looking for a 120     had a 550 2 81 invaders and a 440 trail twister at Waconia, helped me get more interested

[Boomologist]

Two things came to mind.
1. Was the engine allowed to warm up at idle before running hard?
2. Was the fuel fresh? Could fuel have separated and the engine took a drink of alcohol/water

[chaddyg8]

Yes engine was warm.  Up to operating temperature.  No seat on it so i make sure the heat exchanger is warm. And yes fuel was fresh and pre-mixed. I still had break in fuel in it.

[sprocket]

With the new pistons keep in mind the angle on the top is different make sure you don't have a reverse squish that can cause lots of problems. Just because you rebuilt it doesn't mean all parts are the same as years ago. I don't have any problems with any of my liquid engines

[sprocket]

Here one. I’ll try and get a better one later.

this is lean, jetting not correct, air leak, coolant issue, too tight of clearance

[kawhead]

imo  yup

[sprocket]

Here one. I’ll try and get a better one later.

this is lean, jetting not correct, air leak, coolant issue, too tight of clearance

I like to add timing could be off and lastly the crankshaft was that trued ?