Ski-Doo Snowmobiles Forum banner

Pics of meltdown

2K views 27 replies 17 participants last post by  Rev_Rider_03 
#1 · (Edited by Moderator)
Pics are of wieseco pistons, only 500 miles on them for the season. Full pull across a lake in canada. 100 mph and the sled shut down, PTO side melted it could have been bad gas but i think both sides would have been the same. mag side looks 100%. maby a bad gasket on the reed cage? (v force) or maby a bad crank seal (outter has the retainer) and a breather. New main jets (390) and the carbs are clean. any ideas?
 

Attachments

See less See more
1
#2 ·
pics?
 
#3 ·
JPN800 said:
Pics are of wieseco pistons, only 500 miles on them for the season. Full pull across a lake in canada. 100 mph and the sled shut down, PTO side melted it could have been bad gas but i think both sides would have been the same. mag side looks 100%. maby a bad gasket on the reed cage? (v force) or maby a bad crank seal (outter has the retainer) and a breather. New main jets (390) and the carbs are clean. any ideas?
[snapback]703522[/snapback]​
Water in the fuel often affects only one side. If one side gets enough slush in the float bowl to plug the main jet before the other side then you'll only fry one side. that's why running iso in every tank is such cheap insurance. And it allows you to eliminate icing as a factor when diagnosing a burndown.

If you didn't ice it up then she's obviously pulling air in somewhere. Good luck
.
 
#6 ·
JPN800 said:
Pics are of wieseco pistons, only 500 miles on them for the season. Full pull across a lake in canada. 100 mph and the sled shut down, PTO side melted it could have been bad gas but i think both sides would have been the same. mag side looks 100%. maby a bad gasket on the reed cage? (v force) or maby a bad crank seal (outter has the retainer) and a breather. New main jets (390) and the carbs are clean. any ideas?
[snapback]703522[/snapback]​
I just lost the PTO side on my 800X on Sat. on the lake too! There was water in both carbs and dirt. I filled up on the trail from an above ground gas station. I think maybe cause the temp.s are warm there is much condensation in the gas stops on the trail. The dealer told me it cant be covered under warrenty.
 
#7 ·
Hey guys get this stuff called sea-foam and put it in each tank we carry a full can with us everytime we go out. We put about 1/4 can in each tank. Stuff works awesome my buddy has a like 1976 bombardier that basically runs on the stuff lol, it is just like gas treatment but then it also keeps everything clean and does wonders, stuff is great no lie a 1976 and i bet half of the fuel is this stuff and it runs awesome lol. You can get it at Napa so i am assuming any auto parts store. My garage looks like a dealership for this stuff i have shelves of it but it works awesome...Check it out sometime
 
#13 ·
REV*BARON said:
Doesn't look like a meltdown to me.

Looks like a piston ring pin broke off and did the damage.
Is your head smoked on that side? If not then it was a lean condition.
[snapback]705887[/snapback]​
or it looks like you didn't have the c-clip in all the way when you did your rebuild.

..and before any of you say "He had 500 miles on it"! My buddys 99 Mxz 600 had this happen bout 2 weeks ago and the piston looked exactly like that.

Doesn't look like a lean meltdown to me either.
 
#16 ·
both wrist pin clips were still in place, and in good condition when i removed them. the top of the piston was melted by the exhaust side. and it did score the jug but very light. The head was banged up on that side also. Both ring pins were still in place also. I'll know on monday what way i will be going. but i will probably be parting out the sled.
 
#17 ·
The same thing happened to me, mine turned out to be a slight air leak after the carbs. Took mine about 600 miles to let go. Does your piston have a hole in it on the exhaust side or is it of a considerably lighter color than the rest of the piston? kind of hard to see in the pics. My air leak turned out to be between the reed boot and the block.

hope it helps.
 
#19 ·
My 03 800X let go last year. Like others have said, that doesn't look like a lean burn down, it looks like something came apart.

In my 03 800 motor, a thrust washer came apart in the bottom end, and made it's way into the top end. Beat the hell out of one piston and the head, and then fell back into the bottom end and broke the case wide open.

Not very impressed with a thrust washer ripping in half. We found both pieces in the bottom end and in the engine compartment.

Ended up buying an 04 shortblock with the chrome rings. Had Bondi do all the work, and now it flat out rips.

Oh. 4000 KM's on the sled when it happend. Disposable machines.
 
#20 ·
pm'd ya
 
#21 ·
JPN800 said:
both wrist pin clips were still in place, and in good condition when i removed them. the top of the piston was melted by the exhaust side. and it did score the jug but very light. The head was banged up on that side also. Both ring pins were still in place also. I'll know on monday what way i will be going. but i will probably be parting out the sled.
[snapback]706713[/snapback]​
Since it happened on the pto side i bet this has something to do with with venting on the case.Im sure i will catch some flak for this but it is very possible with those crank case breathers that are being sold on here and people are making them that they can suck air back thru the crank case and lean out the pto side cylinder which is gonna lean her down and burn her up .I wouldnt part the sled out ship your cylinder to a repair shop let them fix it and put it back together.I would recommend someone like hildebrands in michigan they can also drill your top case so you can do away with the isoflex grease.And get rid of that crank case breather just my opinion. Good luck
 
#22 ·
Did you get your rave valve machined for the wiseco pistons? Did you warm up the sled (really really good) before the blast across the lake?

I agree, too much damage all the way around for a lean burn down.
 
#23 ·
IBREVIN said:
Since it happened on the pto side i bet this has something to do with with venting on the case.Im sure i will catch some flak for this but it is very possible with those crank case breathers that are being sold on here and people are making them that they can suck air back thru the crank case and lean out the pto side cylinder which is gonna lean her down and burn her up .I wouldnt part the sled out ship your cylinder to a repair shop let them fix it and put it back together.I would recommend someone like hildebrands in michigan they can also drill your top case so you can do away with the isoflex grease.And get rid of that crank case breather just my opinion. Good luck
[snapback]707079[/snapback]​
I'd put money that the breather's not the culprit, and if it is then his inner seal is shot and needs to be replaced at any rate. I have 4123 miles on my sled with a breather installed with no burndowns yet
.
 
#24 · (Edited by Moderator)
i cant get a better pic of the piston to show that it was a lean burn. The corner of the piston cracked off and rattled around in there for a while. Bottom end is still in excelent condition, and no pieces in the case. I also think that the breather might have had something to do with it, ( one inch of white grease in the tube since i installed it and it is still the same color and one inch) being that the rest of the motor is in such good shape and the only damage was to the pto side.
I was thinking of parting it because i found a local 03.5 B/M for a good deal with less than 1000 miles....Plus i need a new summer project


gobblestopper: no machining due to stock bore, and yes they were really really warm. about 20 min trail before the lake
 
#25 ·
JPN800 said:
I also think that the breather might have had something to do with it, ( one inch of white grease in the tube since i installed it and it is still the same color and one inch) being that the rest of the motor is in such good shape and the only damage was to the pto side.

[snapback]707295[/snapback]​
If the breather is the problem, and you still have the 1 inch of isoflex in the tube that's been there from the start, how could it have pulled air through the breather?

For the engine to lean out because of the breather it'd have to pull the grease in first so there'd be an open tract to pull air through. if the grease is still there then you didn't pull air through the breather. I'd look elsewhere.
 
#26 ·
JPN800 said:
i cant get a better pic of the piston to show that it was a lean burn. The corner of the piston cracked off and rattled around in there for a while. Bottom end is still in excelent condition, and no pieces in the case. I also think that the breather might have had something to do with it, ( one inch of white grease in the tube since i installed it and it is still the same color and one inch) being that the rest of the motor is in such good shape and the only damage was to the pto side.
I was thinking of parting it because i found a local 03.5 B/M for a good deal with less than 1000 miles....Plus i need a new summer project


gobblestopper: no machining due to stock bore, and yes they were really really warm. about 20 min trail before the lake
[snapback]707295[/snapback]​
What corner cracked off?

I had a wiseco catch my rave valve and chunk a piece of the piston off (stock bore, drop in pistons). The wiseco's expand and contract alot more than the oem pistons.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top