Lean Seizure

[John.Jr]

I have a 01 KX500,was running 32:1,93 oct.,top end went,piston was a little heated near circlip area thats all but on the exhaust port area near the top above the top ring melted in 2 places' Could this be a lean seizure? Or just time to go. My buddies said they didnt see any smoke while I was riding it. Somebody told me that one of the guys mixed my fuel 32:1 then poured a little that was left in bottle in the gastank on the bike, Let me know something guys,Thanks John.Jr

 

[whenfoxforks-ruled]

Running lean will not erode/melt the exhaust side top of the piston like you describe. Detonation does.

 

[2strokesrock]

If it was a lean siezure adding more oil to the gas will not help, you should beable to raise the needle in the slide a clip or two and that will make it richer.
When a bike is running lean it is getting too much air and not enough gas to lubercate properly, by raiseing the needle it allows more gas into the crankcase resulting in better lubercation.

 

[jason33]

If it was a lean siezure adding more oil to the gas will not help, you should beable to raise the needle in the slide a clip or two and that will make it richer.
When a bike is running lean it is getting too much air and not enough gas to lubercate properly, by raiseing the needle it allows more gas into the crankcase resulting in better lubercation.

really depends on what its lean on , air fuel or oil,gas doesnt lubricate oil does, a wet plug is fuel fouled, oily is black ,and nasty,a bad plug can look either though sometimes


(rule no1)---NEVER LET ANYONE ELSE MIX YOUR FUEL,AND OIL!
no2 there are "smokeless oils out now"
sorry for your problem , i honestly dont know, i wasnt there or am looking at parts,if it was a detonation thing i think it would have melted a hole in the piston,and burnt the electrode off of the plug
(possibly too lean on the oil)

 

[IndyMX]

really depends on what its lean on , air fuel or oil,gas doesnt lubricate oil does, a wet plug is fuel fouled, oily is black ,and nasty,a bad plug can look either though sometimes


(rule no1)---NEVER LET ANYONE ELSE MIX YOUR FUEL,AND OIL!
no2 there are "smokeless oils out now"
sorry for your problem , i honestly dont know, i wasnt there or am looking at parts,if it was a detonation thing i think it would have melted a hole in the piston,and burnt the electrode off of the plug
(possibly too lean on the oil)

Again, for the hundred millionth time, LEAN / RICH only refer to the FUEL/AIR mix and have nothing whatsoever to do with the amount of premix oil in your fuel.

This misinformation has been spread around here way too much.

 

[helio lucas]

http://www.eric-gorr.com/piston problem troubleshooting.pdf

chek it out and point the image for better understanding...

 

[rmc_olderthandirt]

How long has it been since the last top end rebuild?

How long had you been running since the last fill up before it failed?

How about more details, like how hard you were riding. Were you in 5th gear pinned? Or just putting?

Like Jason said, I would be very careful about who mixed my gas. Preferably do it yourself. And you shouldn't be pouring oil directly into the gas tank, the mixing should take place in a can before you put it in the tank. If they added straight gas to the tank, then poured in the oil it would be possible that a layer of straight gas settled to the bottom of the tank and didn't mix with any oil. This could explain it if the failure was right away. I would expect the first set of whoops to mix things up well enough so if the failure was well into the ride it probably wasn't that.

 

[John.Jr]

How long has it been since the last top end rebuild?

How long had you been running since the last fill up before it failed?

How about more details, like how hard you were riding. Were you in 5th gear pinned? Or just putting?

Like Jason said, I would be very careful about who mixed my gas. Preferably do it yourself. And you shouldn't be pouring oil directly into the gas tank, the mixing should take place in a can before you put it in the tank. If they added straight gas to the tank, then poured in the oil it would be possible that a layer of straight gas settled to the bottom of the tank and didn't mix with any oil. This could explain it if the failure was right away. I would expect the first set of whoops to mix things up well enough so if the failure was well into the ride it probably wasn't that.

 

[John.Jr]

yes,to your question,I was in 3rd ,just shifting to 4th and not really nail it but not going slow either and the back wheel slid pulled in the clutch then let it back out slid again then it rolled again.FIRST topend on it since 01 according by my mechanic.Just got it near Christmas,I mixed 1 gallon myself @32:1 and rode it out and had no problems till the next batch was mixed by my buddy.

 

[rmc_olderthandirt]

I would drain the gas out of the tank, put some in a clear jar and take a look at it. Does it look like it has the proper amount of oil in it?

If you are reasonably sure that the oil was mixed properly then I would assume that the seize was due to the long time since the last top end rebuild. If I understood what you said the engine has never had a top end rebuild until now. That would be way beyond the recommend interval for changing out the piston.

Rod

 

[aaronnaland]

Again, for the hundred millionth time, LEAN / RICH only refer to the FUEL/AIR mix and have nothing whatsoever to do with the amount of premix oil in your fuel.

This misinformation has been spread around here way too much.

Im starting to notice hes right

 

[jason33]

lean rich when it is a 4stroker sure ,not a 2 smoker
you can richen a fuel jet on a 2 smoker but its liable to wet foul plugs instead of burning complete

 

[IndyMX]

You need to quit while you're ahead.. You have no idea what you're talking about, again.

 

[John.Jr]

I would drain the gas out of the tank, put some in a clear jar and take a look at it. Does it look like it has the proper amount of oil in it?

If you are reasonably sure that the oil was mixed properly then I would assume that the seize was due to the long time since the last top end rebuild. If I understood what you said the engine has never had a top end rebuild until now. That would be way beyond the recommend interval for changing out the piston.

Rod

Hey Rod a couple of people in this area said the same thing, that it was proboly time for a topend since it was the original, Thank-you for your input