[Glideman88]

Saturday the kid and I went riding. The temps were in the single digits and the trails were freshly groomed and fast! He was riding his '96 ZRT 600 and I was on my 'Ol '90 Wildcat that I've customized with a complete '95 ZR700 engine and drivetrain.

So we're 30 miles into our trip and heading down the trail @ 50+ mph when I decided to punch it (again). The engine took off great and suddenly dropped off, backfired and barely ran. The mag side cylinder was dead! We pulled the sled back to a small town and much to my teenage son's dismay, we both piled on his sled and rode back to the house to pickup the truck and trailer.

Yesterday, I pulled the mag side top-end and found deep scrapes and gashes on the exhaust side of the cyl. & piston. But what was really weird was the rings were completely gone!!!! I found the rings unraveled and almost scratch free in the exhaust pipe!

Has anyone else ever seen this happen?

 

[guitarman69]

I got to admit, I have wrecked and blown up my share of pistons and jugs before, and never seen this. The last One I did was caused from Detination and my rings got hung up on the exhuast port and looked about the same as yours, Short the unraveled rings. Mine just broke off in peices, But I did find out it was caused by the ethenol in my fuel, I have since went back to premium pump gas with no Ethenol

Hope you can figure out what caused your issues

 

[BC_Dan]

Ouch. Like guitarman said, usually when the piston melts and the ring groove can't hold the ring any more, the rings get beat to pieces. That is interesting how yours stayed together. That's actually good, you are certain there's nothing from the rings down in the crank to mess up the bearings (silver lining?)

 

[Glideman88]

Actually the piston isn't melted. It's just scraped and the exhaust edge is peeled up from hitting the exhaust port. The carbon pattern on the crown is almost perfect!

That's actually good, you are certain there's nothing from the rings down in the crank to mess up the bearings (silver lining?)

That's what's amazing! I inspected the crankcase with a "finetooth comb" and all I found was tiny piece of aluminum (about half the size of a head of a pin) resting at the top on the case! I think it probably fell off the jug when I pulled it apart! :dunno:

 

[vikingwrestler]

thats amazing haha what are the chances

 

[RJ Gleason]

Now it's a question as to which happened first, the ring catching and damaging the cylinder, or the plating starting to flake and catching the ring.

 

[musicfreako]

Now it's a question as to which happened first, the ring catching and damaging the cylinder, or the plating starting to flake and catching the ring.

Hmmmm...(strokes beard on chin, and takes a sip of coffee)

 

[RJ Gleason]

From the look of it, I suspect that the plating started to flake first.
I had an old Panther 399 that did the same thing.