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flmx4

07 yz450 locked up

29 posts in this topic

I've seen 2 2007 yz 450' s lock up in the last week. Both started to make a clicking noise and by the time they were shut off they both locked up. Just tore one apart to find valves, head , cylinder, clutch, stator,cam chain, flywheel , all perfect. Rod moves on the crank but the crank is stuck like chuck. Any body else see this yet.

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You're the first. Now you need to elaborate on the cause, since you have the engine apart.

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You're the first. Now you need to elaborate on the cause, since you have the engine apart.

Yup, I agree too many details missing to get all nerveous. I know of about 100 current YZF owners, and the only time the engines blow for no reason (other then never changing your oil), is when the bike gets crashed, layed over on it's side, throttle pinned in the dirt WO with the engine running. Oil cavitation eventually kills the engine.

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Yup, I agree too many details missing to get all nerveous. I know of about 100 current YZF owners, and the only time the engines blow for no reason (other then never changing your oil), is when the bike gets crashed, layed over on it's side, throttle pinned in the dirt WO with the engine running. Oil cavitation eventually kills the engine.[/QUOTE]

I think I just barfed. That sounds like a terrible way to go.:applause:

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And because the YZF is a dry sump, it has to be beyond 90 degrees laid over to starve for oil, at least until half the oil has been pumped into the engine and not retrieved. Plus, both the rod and main bearings can survive on residual oil for a remarkably long time without damage. The piston and cams would be the first to suffer in a situation where oil flow was lost.

flmx4 is a CRF rider, and unless he comes up with a little more solid information than he's offered I see a trolling infraction in his future.

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And because the YZF is a dry sump, it has to be beyond 90 degrees laid over to starve for oil, at least until half the oil has been pumped into the engine and not retrieved. Plus, both the rod and main bearings can survive on residual oil for a remarkably long time without damage. The piston and cams would be the first to suffer in a situation where oil flow was lost.

flmx4 is a CRF rider, and unless he comes up with a little more solid information than he's offered I see a trolling infraction in his future.

What is a "trolling infraction"?

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http://www.thumpertalk.com/forum/faq.php?faq=vb_faq#faq_board_rules

"No trolling. Trolling is starting threads or replying to posts with the purpose of getting a rise out people. For example, starting a thread titled "Yamaha Riders Suck" in the Yamaha bike forums."

Infractions:

http://www.thumpertalk.com/forum/faq.php?faq=board_rules#faq_infraction_warning

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I was going to say maybe the crankshaft bearings but gray says they'll last with risidual oil so idk?

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You people crack me up ! I ride CRF 's so I'm just starting crap ! I only had time to tear it part of the way down the other night, and then I thought I would start a post to see if anyone else had ever encountered this yet. I'm going out to the garage right now to tear the bottom end apart. I will then reply to this again barring I don't need some kind of security clearance to let people know what I found. I work on every type of bike and could care less what anybody else rides.

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No problem. Hundreds of inquiring minds are eagerly awaiting your findings.

You might look into the gear train that drives the starter/oil pump, etc.

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You people crack me up ! I ride CRF 's so I'm just starting crap ! I only had time to tear it part of the way down the other night, and then I thought I would start a post to see if anyone else had ever encountered this yet. I'm going out to the garage right now to tear the bottom end apart. I will then reply to this again barring I don't need some kind of security clearance to let people know what I found. I work on every type of bike and could care less what anybody else rides.

Easy, we just want to know is up, it's all news to us. Plus I have one!:applause:

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The penalty for "trolling" Is Death by Yamaroost. We tie you a CRFwhatever and back up to you and hit the gas WFO. Seriously, I am sorry this happened to you and thanks for sharing your findings. These type of posts are very valuable to us if they prevent an event from happening. Thanks!

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The bolt that holds the top bearing keeper on the left side of the case, snapped the head off and the keeper wedged itself between the crank and the case. The head on the bottom keeper was 2/3 of the way off and ready to let go. The cases maybe salvageable, but any crank that stops abruptly is bad if you ask me. It really looks like it was a faulty bolt, but I'm not a metalurgist. Going to get ahold of somebody at Yamaha tomorrow. I hope it's not a bad batch of bolts.

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I always hate when such minor failures are caused by such big, expensive parts [/sarcasm] :applause:

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I have seen that problem with 07 yfz450 & raptors quads they've been doing this for years. Check your bike on the side of the fender next to 450. If its one of the defective models (for the quads anyways not sure if it holds true for bikes) it will say yamaha.

Hope i can help

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The bolt that holds the top bearing keeper on the left side of the case, snapped the head off and the keeper wedged itself between the crank and the case. The head on the bottom keeper was 2/3 of the way off and ready to let go. The cases maybe salvageable, but any crank that stops abruptly is bad if you ask me. It really looks like it was a faulty bolt, but I'm not a metalurgist. Going to get ahold of somebody at Yamaha tomorrow. I hope it's not a bad batch of bolts.

Any pics? For people who would like to know what to look for.

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