highly unlikely that its the crank........the piston will break because of too much "piston to cylinder clearence".........there will be a little side to side play in the rod....but there should no up and down play
Anyone want to guess what happened?
- Thread starter blastapole
- Start date
highly unlikely that its the crank........the piston will break because of too much "piston to cylinder clearence".........there will be a little side to side play in the rod....but there should no up and down play
my guess... running the 40:1 without rejetting caused it to run lean, ending up with a hole in the piston.
sh*t balls. i have been just reading the first post in threads lately, then post, then read after lol. sucks about the skirt man.
it sounds like what freek said about the cylinder clearance or ive heard of skirts braking off on cast pistons.
If the rod big and small ends aren’t blue then you know it was getting oil. Sound to me like you leaned out. And not because of the 40:1 That will fatten it up a little. Is the piston top some what melted, more so toward the exhaust port? Is the first ring pinched around the exhaust side? Look at your head. Do you have small embedded chunks of aluminum? If so, then it can be only one thing, Lean seizure. And most of the time the skirt will break. Check the Yamaha shop manual. It will tell you how to jig the crank to measure the radial play at the rod small end.
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yes one side of the top piston ring was siezed on probably due to inproper mixture of the gas cuz see i run amsoil and I was mixing it 32:1 and on the bottle it says to mix it 50:1 so i tried leaning it out to 40:1 cuz people were saying that 32:1 was too rich.....
A lot of you refer to the amount of oil you mix in your gas as rich or lean. Your oil mixture should only be described as a ratio 32:1, 40:1. Rich or lean refers to the amount of gas in your air or air/fuel mixture. This is causing way to much confusion on this forum. Now to confuse you even more. A 40:1 oil mix will run richer than a 20:1 oil mix because there is more fuel in a 40:1 mix. I really don’t think you starved your bike of oil even if you were running 60:1 Look at the head and even the plug that was in it at the time. If they both look like the surface of the moon then you had an air leak, way low float level, clogged main jet, ect,ect. “LEAN”
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