30 mile blow up

a bad bore will cause that kind of scuffing to much piston slap i.ve seen it happen 2 a exciter the guy tried 2 hone the cylinder and egged both cylinders made about 40 km and run like shit
 
you keep skating around the ethanol hole. fresh ethanol fuel is not the problem. it what happens to the fuel after it leaves were its made. it degrades and absorbs moisture, once it absorbs enough moisture it phazes. now unlike non ethanol fuel it degrades but doesnt absorb moisture. if there is moisture it collects in the lowest area (bends in fuel lines from fuel pump to carbs, bottom of the tank, bowl of the carb) siphon the water out and you still have good fuel. how with ethanol it absorbs the moisture and carrys it through the fuel system, the whole time collecting more moisture from the atmosphere,once it gets totally saturated it phazes. if you remove the water you are removing the octaine. i cant tell you when the jelly starts to form, but it does, it clogs jets and passeges and its clear some times you look through a jet and it looks clear but take air and blow through it and out pops a clear bogger. all the things that happen to ethanol are what are bad, lean conditions(plugged jets) that lead to blow ups, water that leads to seiziers and bottom end failiers, not to forget that its a solvent fighting to break down the oil. and (yes gas is a solvent but it comes from the same compound thats why you mix to a ratio) as for the base fuel arguement i dont buy it, if the base was not the same you would need more ethanol to bring up the octaine, and 10% is max. as for the customers, the ones i talk to they all get there fuel at different places. i cant guarantee what there getting i can only state the issues with what they got. look at all the posts on here about low speed running issues (thats what most of my customers compaints are) what does every one say clean the carbs!!!!! there is no dirt in the carbs, its what ethanol fuel produces that plugs the carbs,look at how many times some people clean there carbs and cant find the problem, its because of the jelly it starts out with very small amounts and grows like f in a lab experiment! now this doesnt happen while your running your sled but it happens when it sits. i had a customer run his motor all day ran great, sat for a week and had the problem, when did it start to happen? he said it was fresh fuel checked it and it was phazed!
 
if the numbers i got are correct ethanol absorbs (6000/7000ppm) thats alot of water to be putting through a 2stroke with a solvent. all theses things are what is bad about ethanol. if it wasnt for ethanol everone would only have to clean there carbs when they were actually dirty, and that would be far and few between because of the filters! but as you have stated its been around for a while now and people are just used to haveing to clean there carbs
 
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i would have to disagree, that a bad bore would do this, you have two circles, one running inside the other, for example take two pipes and look at it the center line of the rod on the center circle will contact the outer circle first, now bring those circles closer to size on size to spot of contact will grow, and if it was the bore it would have started in the center and worked out and if this was a bore problem it would not have happened to one side only, if it was an oil problem it wouldnt have been on one side only, the intake side. the water logged fuel would hit the side of the piston and roll away from the flow and build up at that area (take an air compresser with a blow nozzle on it, oil a sheet then spray a mixture of water and oil and see what happens) you will get a bigger circle of water than the impact area and the oil will bond to the material inside that area but the water will stop/slow the oil from spreading past it. that is what i believe happened to this motor,and that it was a fresh rebuild didnt help, parts grinding together with water and ethanol as a lube when there should have been oil! everyone keeps missing the fact that the water contains ethanol as stated here a solvent.
 
I'm not skating around "the ethanol hole" as you say it.

Bad , old and poor quality fuel has been known to cause problems well before ethanol was ever used. I don't buy for one minute that good e10 gasoline that was left to sit for 1 week had phased. It was bad when it was put in at best. Regular 100% gas absorbs water too. It's not an ethanol only issue.

From what I see, unless fuel bowls have been allowed to sit and have the gas turn bad, the ethanol actually keeps the internals cleaner than old non ethanol gas.

The reason why used sleds not ever having run ethanol will clog filters and such is that the ethanol cleans the impurities from the tank and everything else those surfaces have acquired over the years. My 78 ski nautique's aluminum gas tank was a slightly yellowy tinted color when I got it about 9 years ago. It was used only up north WI where e10 was non existent from 78-2001. Old gas had sat in the tank from lack of use ( only 200 hours on it when I bought it) and crud deposited on the tank. years of e10 cleaned it to where it is bright aluminum now. Yes, I had to put a couple new fuel water separator filters on it over the years until the varnish was all gone.
 
well give me the amount of water that non ethanol old fuel holds (i believe next to nothing)( and found the answer 0, petrolem base is not water soluible) and lets compare that to ethanol 6000ppm-7000ppm that will solve the water issue. as for the stain in your tank that was most likely from stabil which was used in those years(and some still today) in winterizeing.this ethanol stuff is just like politics the media and the dems keep saying that the reps have done all these bad things, yet go look up history of the congress and you will find that the dems have been in the majority 90% of the time in the last 60 some years. just saying there is alot of misleading going on!
 
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as for the bad fuel always being around, that may be true, but the effects are different between then and know, back then there would be problems in the combustion chamber(detination) if the fuel was bad (low octaine), and after a long long time sitting with fuel on, tarnish and a calcium like build up, but i have never had a jet plug with tarnish. now there are problems through the entire motor and allot more scores than back then, and yes everything looks clean but there is a sustance that the fuel creates that looks like snot or jelly that plugs up everything, and i have found nothing that touches it, i have tried all the cleaners around and they all do the same thing push it around nothing desinagrates this stuff, a couple of times in the sonic cleaner will usually clean it after wire brushing and pokeing but thats it. back in the day with old fuel, carb clean and your done. so there is a big difference!
 
had something similar happen to my 99 srx after a rebuild where i bought aftermarket pistons. pistons were the right size, but i didn't know these needed excessive warm up time compared to the stock pistons. result was a cold seizure and another tear down. I also think a missing bolt on the intake boot caused the burn down cylinder to run lean, adding to the heat. Were all the gaskets tight?
 
motor tech said:
as for the bad fuel always being around, that may be true, but the effects are different between then and know, back then there would be problems in the combustion chamber(detination) if the fuel was bad (low octaine), and after a long long time sitting with fuel on, tarnish and a calcium like build up, but i have never had a jet plug with tarnish. now there are problems through the entire motor and allot more scores than back then, and yes everything looks clean but there is a sustance that the fuel creates that looks like snot or jelly that plugs up everything, and i have found nothing that touches it, i have tried all the cleaners around and they all do the same thing push it around nothing desinagrates this stuff, a couple of times in the sonic cleaner will usually clean it after wire brushing and pokeing but thats it. back in the day with old fuel, carb clean and your done. so there is a big difference!
Click to expand...

There is a product that dissolves the ethanol snot..takes a couple days but works 100%..Motorcraft Carburetor tune up cleaner, find it at a Ford dealer.
 
who does a bore job without checking the size (tolerance) of the piston to match the hole? If that was a dealer that did that to my sled, he would be buying and installing the NEW one free of charge. When you bore or hone a top end, you cannot do it without measuring the piston first period.
 
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