30 mile blow up

horkn said:
For me just seeing the cylinder makes it a non rotary motor .
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not rotary motor, rotary valve motor. Lots of rotaxes use a rotary valve design, instead of reeds like on other motors.
 
he was driving with wife and friend he was leading and following hes very careful and not speed racer there was very little powder in the air
 
Why

Why would anyone leave gas in the tank all summer and leave it in there and expect everything to be OK. Drain all that crap out and put it in your car or truck......they will burn it. Put 100% fresh gas in the sled. I do sort of wonder though....if the gas was so bad why is there no sign of detonation on those pistons? Maybe because the sled is in stock form and compression is not high???

Madmatt
 
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smokingcrater said:
not rotary motor, rotary valve motor. Lots of rotaxes use a rotary valve design, instead of reeds like on other motors.
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Yeah, I am well aware, but maybe others are not. I had a couple rotary valved motored doos in the 90's.

I can only think of 1 rotary motor in a sled from the factory...Evinrude.
 
no1chevyboy said:
well here it goes, when he called me and told me the story that i have put on here my thoughts where intake score, a couple of things can do this (dirt, port chamfer not done on intake side for some reason,water) but after he sent pics this eliminated dirt,port, as the scoreing started between port openings and on the same spot on both pistons one first then the other, which must have to do with flow through motor so where left with water, had him pull fuel sample and wala cloudy at first then it cleared the problem was ethinal!!!!!!! (satans piss) LOL the fuel was on the verge of phaze and with that and a fresh rebuild thats what took out this motor, and he goes out of his way to get non ethinal fuel and got this at a pump that said no ethinal ,now he filled two sleds there his first then the other one and the other one is what they doubled on to get home so my guess is the three gallons that were in the tank phazed then the fresh fuel did what it could to absorb the phaze, all the fuel was purchased at the same station, his former favorite oh and the three gallons that were in the tank were summerized with lottery juices that are suppossed to preserve your fuel.
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Maybe try some periods and capital letters. As is, I'm not quite sure what you're trying to say.

Lottery juice? What the hell is that?
 
You are there and looking at the parts first hand, But I would not be 100% convinced it was the ethonal. I would still be looking deeper, ethonal has taken a bad rap, but it is too easy to blame. Alot of different symptoms could have done this. If all of the sleds filled up at the same station, why not all engines seized? I think I would investigate much more before reassembly of new componets. Good luck Al
 
Either way, I hope the owner sucks out all of the gas and replaces with fresh, including any which is still in the fuel pump/lines. I thought the engine siezed, but if it just lost power, then yes, it could be as simple as fuel contamination of alcohol and water. The seperation will wipe all oil from the intake. We are still in learning curve of what the effects of ethonal will produce. Best of luck Al
 
no1chevyboy said:
Well here it goes, When he called me, and told me the story (that I have put on here) My thoughts where intake score - a couple of things can do this (dirt, port chamfer not done on the intake side for some reason, water), But after he sent pics this eliminated dirt, port. As the scoring started between port openings, and on the same spot on both pistons, one first then the other. Which must have to do with the flow through motor. So we're left with water. Had him pull a fuel sample, and wala, cloudy at first then it cleared. The problem was ethanol!!!!!!! (satans piss) LOL! The fuel was on the verge of phaze and with that and a fresh rebuild thats what took out this motor. AND, he goes out of his way to get non ethanol added fuel, and got this at a pump that said no ethanol added. Now he filled two sleds there, his first, then the other one, the other one is what they doubled on to get home. So my guess is the three gallons that were put in the tank in the summer phazed, then the fresh fuel did what it could to absorb the phaze, all the fuel was purchased at the same station. his former favorite! Oh and the three gallons that were in the tank were summerized with lottery juices (stabilizers) that are suppossed to preserve your fuel.
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Chevy Boy, I am leaning towards the "old fuel" theory also. There is ALOT more humidity in the summer time than in the winter time so this may have also added to the "extra" water in the fuel. Your theory sounds rational to me.

How is your friends sled jetted compared to his wifes sled? Is his jetted a little leaner?? This may also have added to the already bad scenario.
 
her sled is a 500 fan i think, when he rebuilt it he up graded the intakes,up graded the head,and pipe,he did all the fattening up of the carb per upgades request bigger main, raised needle, same pilot i believe. id have to call to get no.s. he said plugs were dark brown and piston tops were wet and dark.the wifes sled was stored empty and her fuel checked ok ! the biggest problem is if the fuel would have been non ethonal (like advertised/purchased) it may have lost octaine but would not have absorbed water or phazed !
 
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I don't know about the old fuel idea. He likely does the same thing to both his and his wifes sled at the end of winter. If his wifes sled is like my wifes, she has even older fuel because he hits the last ride. But her sled is fine with same if not older fuel and no extra oil added?
 
fourbarrel said:
Something nobody mentioned but the carb boots are a known weak area on Rotax engines,I've seen too many of them around here crack and cause engine failure so if he hasn't checked/changed them I'd for sure give them a VERY close inspection.
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i'm sure you already checked it but this is a very notorious problem with ski doo's
 
bad fuel, bad intake boots on a non rotary doo motor, dirty carbs, and poor judgement caused the failure (all common problems). text book early season (first ride) burn down. just because you add stabilizer, doesnt mean it will be good to go, when you think it is time to ride.

the best thing you can do to ALL motors is put in an in-line fuel shut off, and run the sled till it dies, eliminating all fuel in the carbs. or drain the float bowls after storing it for the year.

for the first ride, drain ALL THE GAS OUT OF THE TANK, AND PUT IT IN YOUR CAR. add fresh, proper octane fuel to the tank, and go for a short and easy shake down run. better safe than sorry.

i am sorry for your friend. would suck to spend all that time and money and have it fail when it was running before the rebuild. good luck to him. ski
 
no1chevyboy said:
her sled is a 500 fan i think, when he rebuilt it he up graded the intakes,up graded the head,and pipe,he did all the fattening up of the carb per upgades request bigger main, raised needle, same pilot i believe. id have to call to get no.s. he said plugs were dark brown and piston tops were wet and dark.the wifes sled was stored empty and her fuel checked ok ! the biggest problem is if the fuel would have been non ethonal (like advertised/purchased) it may have lost octaine but would not have absorbed water or phazed !
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The big thing is buying premium fuel from a gas station right now. I don't know about where you are but here no one buys premium fuel. It is too expensive so it just sits in the tanks and collects condensation (water). You go out for a ride, engine injests water or you have ice formation in the jets (low pressure area) and you have a lean burn down. Simple as that. The ethanol in the fuel doesn't matter. It has been in our regular fuel up here for years.
 
To avoid engine stall due to "slugs" of water in the fuel lines interrupting fuel flow, the fuel must exist as a single phase. The fraction of water that an ethanol-gasoline fuel can contain without phase separation increases with the percentage of ethanol.[41] This shows, for example, that E30 can have up to about 2% water. If there is more than about 71% ethanol, the remainder can be any proportion of water or gasoline and phase separation will not occur. However, the fuel mileage declines with increased water content. The increased solubility of water with higher ethanol content permits E30 and hydrated ethanol to be put in the same tank since any combination of them always results in a single phase. Somewhat less water is tolerated at lower temperatures. For E10 it is about 0.5% v/v at 70 F and decreases to about 0.23% v/v at -30 F.[42]

There ya go
 
why don't they just ban the ethanol stuff.That is so stupid what is going on with that fuel.Give us straight gas and no fillers..what's the problem with that..A conspiracy seems to be existing to eliminate all 2 stroke motors then and force everyone to go 4 stroke and less pollution..The 2 stroke motor manufactures are sure gonna get rich on selling parts for tons of burnt down motors..Did I say a conspiracy may be looming.....
 
BURN DOWN SUCKS!!!!!!

Tell your friend to keep a positive attitude and not assume anything caused it!!! look at every single little detail when he installs his new bullet as to not roach another one!!!

Sorry about the bad luck!!!

Wish I could help!!!
 
no1chevyboy said:
the article you posted is about the effect on 4stroke motors,(the fuel mileage declines)and im not sure about the numbers in it. but non ethonal fuel, example (mtbe) only holds 60ppm and doesnt phaze, if there is condensation it goes to the bottom of the tank were it is sucked up to the motor and the motor getting just water and maybe a little oil will not start at all. now take a 5 gallon bucket, put 1 gallon of 91 octane non ethonal gas in it, then put 3 gallons of water mix it up as much as you want, then let it settle you can remove the 3 gallons of water and the fuel is good to go you still have 91 octane fuel. now put in 1 gallon of 91 octane ethonal which holds 6000/7000 ppm and 3 gallons of water mix it up as much as you want,let it settle then remove the water at the bottom and what you have left is ? 80 octane low enough to burn any 2 stroke. and if this happens in your tank were the amount of water will be way less ,your motor will run on the water, ethonal,and oil. they dont idle that good but they like rpms. and with that combo water, and a solvent, its the kiss of death for a 2 stroke. then leave it sit for awhile, your whole system will get this clear jelly like substance, that could be other colors depending on what additives you have in your fuel, that will cling like glue in passeges and on internal fuel system parts (fuel tanks, lines, fuel pump, floatbowl. you have to be very careful with this fuel and not let it sit.
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What you said is correct. The non ethanol fuel would not absorb the water. However the fact that no one buys premium high octane fuel except us people with fancy toys, the fuel in the ground tanks at the station is full of water because it sits (condensation). Even if the fuel didn't have ethanol in it, the water is still going in your tank and would still make its way through the carbs into the engine. That is why they have heated carbs to prevent the water going through them from freezing (gasoline won't freeze till like - 80F but will form wax crystals) Its not gonna sit in the tank and seperate when your swishing it around. You're better off to buy a lower octane ( if you can run it) with ethanol in it because there won't be water in the fuel if it is fresh like it will be because its being sold everyday.

Think of gasline antifreeze, it is Isopropyl alcohol and makes water soluble in gasoline. Doing the same thing as ethanol (makes fuel absorb water) I run the stuff all the time, never had a problem yet touch wood. I can't understand why there has been so many burn downs this year and last.
 
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