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Curtybird95

Yz 450 engine knock?

23 posts in this topic

My 2003 yz 450 started making a knocking noise after i was riding. I was hitting the rev limiter and once i slowed down i noticed the noise, i heard they r loud but is this normal? Heres a link of my bike and the noise on youtube

Thanks for the help.

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I did not check the oil for metal, i just got the bike and rode it for two weeks then this happened? How do you replace a rod? Will it be okay to ride? I have a big trip coming this weekend and dont have time to fix it...

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How will i know if the tensioner is bad? And what about the crank? Im new to working on these bikes so need all the help i can get...

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if the crank is the cause then riding it will only due more damage,if it snaps then you could ruin the complete engine.My advice is get somebody who knows how to check these things,definately don't ride it the way it is.

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if you ride it like that then that's a possibility,as of now most likely just a crank.You can check the tensioner by taking out the end screw and use a flat top screwdriver to tension it,I think to tension it you go counterclockwise but not 100% sure on that now.

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This is the hard truth.....that bike is smoked. Cancel the trip until it's fixed.

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If the crank is the cause then riding it will only do more damage. If it snaps then you could ruin the complete engine. My advice is get somebody who knows how to check these things, definitely don't ride it the way it is.

x2

Is there any possiility that it could just be the timing chain tensioner?

Sure it's possible, and there are a few other possibilities too. Many responders believe the noise could be something serious, but most of us are giving you an educated guess and nobody on an internet forum can guarantee you what the exact problem is. To me, it sounds pretty healthy except for that suspicious knocking sound... I don't know what the noise is but I suggest that you not ride it until it's fixed. What is the bike's history? Have you hit the rev limiter ever since you got the bike two weeks ago? Does it have any performance upgrades or aftermarket parts? Do you have any information on valve checks, oil changes, or other maintenance history? More info would be useful for anyone here who wants to help you.

You said that you aren't very familiar with the bike, so if you want to get it diagnosed and fixed in time for your big trip next weekend, take it to a professional and be prepared to spend some money. If you want to fix it yourself, it's going to take some time to get it done. Good luck!

Edited by DGXR

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To tell you the truth I think its not that bad. Every yz450f ive ever heard has knocked, yours doesnt knock to out of the ordinary as to what ive seen and heard. I dont know if your not but make sure your running 93 octane and that your valve clearances are set to spec. Also if the bike hasnt been taken apart in a very long time it may be a good idea to get a gasket kit and dismantle the top end. Simply look for anything out of the ordinary and check the dimensions listed in your manual. Remember even with a new top end and everything perfect that engine is loud and will make a tapping noise no matter what. My 2009 yz450f has ever since Ive owned it and so has my buddies 2007.

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Actually i just watched the video again and listened and heard it knock even when you gave it throttle, thats not normal, you have to take that puppy apart asap. sorry

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It has hot cams stage 2 and a yoshimura pro series exhaust , now the bike is completetly locked up, i cant even kick it, the kick start is frozen.. And i cant push it in neutral, i have to have the clutch in otherwise it wont budge, any ideas?

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It has hot cams stage 2 and a yoshimura pro series exhaust , now the bike is completetly locked up, i cant even kick it, the kick start is frozen.. And i cant push it in neutral, i have to have the clutch in otherwise it wont budge, any ideas?

If you are SURE it's in neutral and the kickstart is locked and the countershaft won't turn without a pull on the clutch lever , all I can say is you have a serious problem with your bottom-end, maybe the crank or gears or gear shafts or something else. Time to finally do something and get it looked at. Let us know what you find. Good luck.

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Sounds like your crank is gone brother. Those bearings most likely seized up on you, if you check your oil filter you will likely find some metal shavings in it.

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