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Cody miller
https://www.ebay.com/str/cmill987?mkcid=16&mkevt=1&mkrid=711-127632-235…
My point is it either hits or doesn’t. The piston and crank can’t move that much unless the rod or rod bushing is coming apart and then yeah they could hit.
Pinit racing on you tube claimed their bike was low on power and the x dimension was way too tight from the factory. That could damage the rod and/or crank over time. I think the early calibrations were too lean on top which is risky. TPS setting is important too and they are not getting set consistently.
They can and do hit from day 1...
Some live to tell others not so much.
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All i can say is it's a known issue. Someone posted actual measurements of the difference in skirt thickness and most don't fail immediately.
100 hours on a 2 stroke crank is a lot if ridden hard. And you have to be precise with the X and Z settings on top end rebuilds. Just putting in one base gasket (what size????) isn't the way to go. You have to check X once jug is on and torqued even if you used the same thickness as what came off.
I'll guess 3 things - X was off, crank was worn, and you were detonating on 92 octane. I run a blend of VP110 and 92 to hit about 103 octane at 40:1. 20-25 hours per piston ridden pretty hard. Ours are all 125s but there's little real difference in material or maintenance.
ah man that's a bummer sorry to hear that! Sounds like you did everything right just some bad luck. Glad you didn't get hurt let us know what you find!
I’m guessing you measured the original base gasket thickness and installed the same one?
Yes
Small end failure. It got tight and popped. Notice the color of the bearing surface. That is not an something that is an instantaneous failure but rather it got hot and then popped. These type of things often fail at later times than when the damage was done. Saying it didn't have to be damaged on the day it failed, only that it was previously damaged and finally failed.
Probably the crank or wrong head base gasket my 17 husky had 4 options for base gasket thickness, if it’s hitting head that hard for 20 hours I can see this happening.
Holy crap! That thing disintegrated. Tbh, I’ve never seen that before. It would be nice if the dealer rebuilt it for free or free labor. The problem is that the stock parts are obviously suspect at this point. I’m not sure I would feel comfortable putting OEM piston, head, or crank in it.
We asked GasGas what they could do for us, and we got nothing.
Wow, that sucks. Looking at that failure, even if it had an air leak, stuck a piston, or wrist pin failure, there is no way that the head should have failed like that. At most it’s gonna just seize up and maybe blow the head or base gasket. It’s a clear manufacturer failure. I guess it doesn’t do any good now unfortunately. Just crazy 🤔
Would it be cheaper just to get a new crate engine? lol
Yes if we could find one
That's a cheap looking base gasket.
And everything looks hot in there. Crank looks hot, cases look hot, everything has a "fast guy in sand" look to it.
Pit Row
Everything is OEM 🤷♂️, and it happened at Glen Helen
100 hours is nothing as long as you don't buy into the 60:1 and leaner BS for the 250s and 300s
Jet for 30-40:1 and your crank will be happy for a couple hundred hours...
At some point it got hot or dried out. The chance of a good bearing failure are slim at best.
I hate to agree with @MxAddic but the small end looks burnt, overheated, from the blackening of the base gasket, I'd guess an air leak through the base gasket, causing it to run lean.
I definitely don't dispute that.
Running 32:1 vs "recommended" 60:1 means it was running at a leaner air to fuel ratio than intended. OP said "all stock", so no jetting changes made to compensate? Not sure how good the stock jetting is on these bikes though... For all I know it was dialed with the premix ratio change.
Either way, feels like an air leak would be the most likely culprit as mentioned above. Or, the OEM cranks are occasionally garbage.
Holy crap thats grenaded alright.
Looks very dry for being the bottom end
For these bikes, the OEM base gaskets come in 5 thicknesses - .20, .25, .40, .50, and .75mm. The one in your bike looks like a .25mm. I have all of them here and the .25mm is the only one that is white like that. All the others are green. Most of these bikes come from the factory with a pretty thick setup to get the X dimension with the piston flush with the top of the cylinder. Most bikes will have 1 or 2 stacked to get around .75 - .90mm total of gaskets. Maybe you measured wrong and picked the wrong one? I have never seen a stock KTM 2-stroke with one single 0.25mm gasket. Compared to 0.80mm, 0.25mm is really thin and will tighten the squish a ton. Anyway, you can pull that gasket off there carefully and measure it with a caliper and let us know what thickness it is. They really don't compress a whole lot and you can usually distinguish what thickness it was.
That sounds logical, but if you go back to page 1 and look at the other photos; the piston crown and combustion chamber don’t support your lean theory.
Good point, plug, top of piston would be white, maybe no premix in the fuel.
At some point in is life, option 1. I would not call the OP a liar if he said no. Option 2 would be run low/out of coolant previously. There are couple more with decreasing odds.
Don’t really matter, poor guys engine is toast.
Definitely had premix, I only know this is for sure because we used the rest of it when we mixed gas for DITD when it happened 😂
Engine is 100% toast, running total for parts so far is at 4k and we haven’t even checked past the rod
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