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XR250_RIDER_14

Blown up or not?? 03 450 Please Help!!

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I was riding my 2003 yz450 today pretty hard when all of the sudden it sputtered and it died really quick. I was probably about 5/6 throttle for about 30 seconds. I kicked it again and again and it seemed to be harder to kick like there was more friction and not compression. I got it to start up and ran it again for about 1 minute and it died like it did before:foul: .

I can't get it to start anymore. I took the plug out and kicked it over and its like the plug is still in there!! Is this normal for a 450? It is really hard to kick over even though there is no plug in it.

Water in the gas?

plug is fine brown color (good)

I'm pretty sure that some bearing has siezed from heat or something with the piston and rings.:worthy: In my opinion that is.

I have been running new oil. Its been changed probably 2 hours of riding ago and is still a golden color. Castrol Syntec 10w40 for motorcycles. Oil level was good and I DID have antifreeze in it and the radiator was full.

ANY IDEAS PLEASE PLEASE HELP ME:cry:

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Steps I need to take to finding the source? If the piston and rings are ***#$d up then I dont want to kick it anymore right? Wouldn't that just scratch my cylinder even more.

By the way when I ran it that hard I was doing like a 70mph wheelie about wide open for about a minute. Would that mess up the oil flow resulting in what happened?

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Sounds like its time to tear it down and check it over. A possible big end bearing failure comes to mind, but you can't be sure until you start taking it apart.

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By the way when I ran it that hard I was doing like a 70mph wheelie about wide open for about a minute. Would that mess up the oil flow resulting in what happened?

too much and too fast wheelie time I suspect? :worthy:

if it is what you suspect...get ready to get your wallet out...:D

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By the way when I ran it that hard I was doing like a 70mph wheelie about wide open for about a minute. Would that mess up the oil flow resulting in what happened?

With the way the oiling system is laid out, and if you had the right amount of oil in it, no.

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Does anyone know or have any idea what I am looking at? piston? Lower end ? What is the best brand for the lower end. Is it crank and rod or do you buy them separate for 4 strokes

JE or Wiseco?

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Does anyone know or have any idea what I am looking at? piston? Lower end ? What is the best brand for the lower end. Is it crank and rod or do you buy them separate for 4 strokes

JE or Wiseco?

No one here has x-ray vision, let alone the long distance variety. Tear it down.

For the most part, seizures will involve one or more of 3 sets of parts:

The piston/cylinder

The crank/rod

The cams/head

I recommend you use OEM replacement parts, or if you find you need to replace the cylinder, a big bore kit from somewhere like Luke's Racing that offers an exchange allowance for your old damaged one. Be sure you check the oil pump.

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You probably have seen me up at victory lane.

I suggest you get a 2nd opinion....wheelies can not seize these bikes. I was joking....Anyone qualified to assist in your area?

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I thought I remember hearing problems of de-compression plugs blowing out on older YZF's?

Could that be a possibility? :worthy:

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