SportPart piston????

[ZL50068]

I blew my motor on my 2002 ZL 500 last winter with 5000 miles on it. I replaced one cylinder and both pistons. The pistons put in were sportpart brand. Well, 400 miles later, same damn thing happens on the same cylinder(mag side I believe). So, we sent the pistons back to see if we can get new ones under warranty. Now, I did take the sled to Cooke City prior to both blow-ups. I believe I was jetted correctly, but maybe the parking lot to riding areas elevation change had something to do with it? My MAIN question is, does anybody have experoence with sportparts pistons and why do you think my motor failed with 400 miles on a rebuild? thanks...........

 

[ZL50068]

ttt eh

 

[ZL50068]

ttt, anybody??

 

[Snorider]

Never delt with those pistons, but do you remember what your plugs looked like and depending on how bad the piston was damaged the wash on both pistons, or at least the one that wasn't damaged?

And what failed on the piston?

 

[jsledder]

Do you have pictures of the piston? What exactly happened? Did it lock up, skirt break, pop a hole in the top, ???

 

[ZL50068]

The first time, the rings stuck and ate up the cylinder and damaged the head. The second time is was very similar. I do not have pics of the piston, but the rings were stuck, the piston was scuffed, the head had lots of chips in it. The plugs everytime I checked them were light brown and occasionally a little blacker, so no lean burn down

 

[ZL50068]

ttt eh

 

[jsledder]

Did you measure the piston to wall clearance and the ring end gap to be sure they were within specs?

 

[Burndown1]

I will say the so called parking lot that you are talking about is called Pilot creek parking lot. The area before the parking lot a corner used to be called Phazer corner. The sleds would run good at cooke ,daisy or lulu. But on the way home bang down hill and lower ele. down it would go. That area has got alot of pistons in the last 30 years.

 

[ZL50068]

Did you measure the piston to wall clearance and the ring end gap to be sure they were within specs?

Hell man I dont think we took none of them measurements. See, I am having a friend help me in all of this. But what would make them pistons go bad after 400 miles??