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rubberband-man

2008 yz450 Engine quit PLEASE HELP

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I was riding at the track yesterday, landed a big table---on the gas when i touched down, and suddenly i lost throttle response and the engine bogged down until i stopped, at which point i pulled off the track and can now not get the bike to start. I noticed my oil drain plug by the shifter was loose and leaking some oil, but i tightened it up and the leak stopped, checked the oil and there is still oil, but it was low. I added oil. i try to kick it, and it feels a little easier than it normally is to kick it, but it's always been really easy to kick start. it's a 2008 yz450. oh yes--there was no smoke coming out of anywhere, but when i tried to kick it, smoke would come out of the tube that comes off the top of the engine and empties by the shift lever. Please help. Thanks

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check for fuel, (is the plug wet) check for spark, (pull plug ground to engine see if it sparks), check compression or do a leakdown test if you got spark and fuel

list of possibles is as long as your arm but above tests will cut it by 2/3.

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I was riding at the track yesterday, landed a big table---on the gas when i touched down, and suddenly i lost throttle response and the engine bogged down until i stopped, at which point i pulled off the track and can now not get the bike to start. I noticed my oil drain plug by the shifter was loose and leaking some oil, but i tightened it up and the leak stopped, checked the oil and there is still oil, but it was low. I added oil. i try to kick it, and it feels a little easier than it normally is to kick it, but it's always been really easy to kick start. it's a 2008 yz450. oh yes--there was no smoke coming out of anywhere, but when i tried to kick it, smoke would come out of the tube that comes off the top of the engine and empties by the shift lever. Please help. Thanks

Pull the left stator cover off and check 4 a stator bolt broken or broken coil wire. The 08 stator was mounted with 3 bolts and some people had problems with loose bolts or broken coil wire from excessive vibration. This was fixed with 4 mounting bolts in 09. Good luck!

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It very well could be that your cam chain jumped time. When you came down on a load it may have skipped, this would also explain the easy kicking if the cams were not timed correctly. I would take the valve cover off and make sure they are dead on in time. If the bike has over 30 hrs it should have been replaced.

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i checked the spark plug first, there is barely a spark and it is pretty black. i'm going to get another plug tomorrow, then go through all of your suggerstions if that doesn't work. thanks for your help.

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