What causes this?

[polarisrider1]

I find this as brand new information. The XLT triples had issues when they went to a mono head design. The 90's Polaris sleds had bullet proof Fugi Heavy Industries Motors in them still, both liquid and fan models. Then The bullet proof 500/600/700/800 Liberty motors came out. There were issues with the storm and ultra triples mostly crank issues. This piston thing can you give me specifics. There is not much in the Polaris line up that I have not owned.

 

[mjkaliszak]

This thread going hostile ? Pretty hard to say for sure what caused the grenade pin to pull after 1 lunging it home for 40 ? I Like the "expensive oil " theory !

 

[polarisrider1]

This thread going hostile ? Pretty hard to say for sure what caused the grenade pin to pull after 1 lunging it home for 40 ? I Like the "expensive oil " theory !

No hostility here. In Tech talk it would be great if real help would prevail. The longer a link runs in this topic the farther from the question it seems to get. Making it about useless. I hope John and Paul can split this tech section into brand specific sections so true loyalist of their brands can truely help each other out. Think about if you were in the topic posters spot, crap posts do nothing for that person or this forum or the advancement of this wonderful thing we all share, Snowmobiling!

 

[bouncer]

The piston pin clip will let loose if the pin is thusting against the clip
One cause could be a bent rod.
Another could be worn upper or lower rod bearings
Check the lower rod bearings and always replace the top pin bearing when
replacing a piston. Good luck.

 

[mjkaliszak]

No hostility here. In Tech talk it would be great if real help would prevail. The longer a link runs in this topic the farther from the question it seems to get. Making it about useless. I hope John and Paul can split this tech section into brand specific sections so true loyalist of their brands can truely help each other out. Think about if you were in the topic posters spot, crap posts do nothing for that person or this forum or the advancement of this wonderful thing we all share, Snowmobiling!

I was having a little good hearted fun. What I said was (is) true. Pretty hard to tell what caused this from the facts presented . Next time what should be done ( IMO ) when the sled burns down or grenades is to STOP. Pull the belt and tow it back. (Running )Turning the motor over for another 40 miles or any distance for that matter can only create more problems and damage. That motor should be gone thru there is bound to be collateral damage to the crank & bearings after that event.

Furthermore don't call my post "crap". It shows a lack of respect to a fellow JD member.

 

[maxwell]

I was having a little good hearted fun. What I said was (is) true. Pretty hard to tell what caused this from the facts presented . Next time what should be done ( IMO ) when the sled burns down or grenades is to STOP. Pull the belt and tow it back. (Running )Turning the motor over for another 40 miles or any distance for that matter can only create more problems and damage. That motor should be gone thru there is bound to be collateral damage to the crank & bearings after that event.

Furthermore don't call my post "crap". It shows a lack of respect to a fellow JD member.

I think he as directing the comment at me. If not, you can assume he was directing it at me. I am looking for pics and detailed information of my Polaris piston skirt issues (in which I replaced with Wiseco pistons) to correct a piston issue.

From here on, I am going to PM Toddspolaris with the pictures as to not take this topic any further off course.

 

[dopp]

THAT IS DEFINETLY NO OIL.
When rebuilt mix oil in gas and pull the oil injector hose off to check for oil flow (while running)

 

[dab102999]

Dopp, If u pull the injecter hose won't you be sucking air??

 

[doomsman]

40 miles steady speed were you in the back of the pack eating snow dust, are all the filters in place. Just asking looking for the why it happened.

 

[G]

toddspolaris - It has been awhile since I have had to put in a piston in a two stroke but in the olden days we used to have troubles with the Wiseco pistons. Correct me if I am wrong but piston to cylinder clearance is very critical when using Wisecos. We were sticking new pistons because one material expanded faster than the other. This was on early 90's Pols. Sorry to hijack the thread. If the sled was driven 40 miles with that piston you need to take the engine down to nothing to clean out the shrapnel. This means splitting the cases - everything.

 

[sundown]

yamaha 600 b/o piston

I've seen several of these on that vintage 500 & 600's. The problem is the ports were not chamfered enough and usually around 5-6k miles the ring catches the ports and tears things up. Replace cylinder making sure chamfer is OK. Take the other cylinder off and rechamfer that one. Replace piston &rings (I like Wiseco, but OEM will be OK) and you should be good to go. I've not seen the problem reoccur after this repair.