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Engine locked up

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My son has a 03 yz450f; He had just got on his bike after cooling off and he was going down a straight away and he shifted down for a turn and the engine locked up and died. We took it to our local Yamaha dealer and the mechnic said it might have droped a valve, and if it did it would cost about $2-$3000. to fix because you would need to replace everything. We left the bike for them to check to see what could be wrong with it before we decide what to do. The bike was running great before this happen, We had changed the oil the night before and we need everybodys help any ideals what we should do.

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Well, first off, the mechanic was giving you worse case numbers. If it did drop a valave, you could be as lucky as merely needing the valves redone. Next worse is a the addition of a new piston and rings. Next would be a replacement head, then a replacement barrel. Next might be a new crank and case cleaning.

A lot of possibilities. Really need to wait for the tear down to get a real cost of the damage.

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Yes that is what I'm waiting for is the good, bad, and ugly or maybe something simple. I will let you know what I find out.

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how may hours on the bike? my bike locked up because of a stretched cam chain that allowed the exhaust cam to slip causing the piston to hit the valves.

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We had just bought the bike about 4 weeks back and we went to the track 4 times and changed the oil 3 time and cleaned the air filter every time. I would say about maybe about 7 hours. If I get this bike back with good news (not too costly ) I will get an hour meter for the bike.

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The dealership called today and said they checked the valve clearance and they were good but the bottom end was binding up and they think it might be a rod or crankshaft. They will do the bottomend with all new parts,crank,pistion,rod,etc and they advised me to go ahead and have the topend done also with new valves etc. they will do the whole job for $1900. What do you guys think?

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The dealership called today and said they checked the valve clearance and they were good but the bottom end was binding up and they think it might be a rod or crankshaft. They will do the bottomend with all new parts,crank,pistion,rod,etc and they advised me to go ahead and have the topend done also with new valves etc. they will do the whole job for $1900. What do you guys think?

haha..i say you get a two stroke :)

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seems like alot of work to be done for only having 7 hours on the bike. unless u ran it out of oil. my boss ran his rhino low on oil and the bill was $3000.00.

so if that is what happened i would say it seems pretty fair price

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The 7 hours is only how long we have had it. No the Oil level was right on the full mark after the incident. The mechanic said that the air filter was dirty and it might have sucked something into the lower end to cause the problem. We had cleand the air filter the day before. I guess I will invest into another filter to have on hand or buy some skins that fo over the filter and rip one off when it gets dirty at the track according to the mechnic.

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The mechanic said that the air filter was dirty and it might have sucked something into the lower end to cause the problem.
I find that interesting. He says it dropped a valve, and that this was caused by a failure of the lower end, which in turn was possibly caused by dirt being introduced through the air filter, which does not lead to the lower end. In truth, it could be either a lower end or a valve failure, or something else, but it's beginning to sound like the "baffle them with BS" ploy a little bit.

BTW, it wouldn't hurt to freshen the filter mid-day, but a properly oiled, high quality filter should be capable of dealing with a day's use and not pass anything major. Mine survive a 2.5 hr race in the SoCal desert OK.

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Guess THIS MECHANIC does not know the difference between a 2 stroke drawing in fuel and air compared to a 4stroke.

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You should seriously learn to do the stuff yourself i aint tryin to be a dick about it but it would save you a ton of money and you wouldnt have to listen to all the BS they say it could be . Try doin it yourself its not as hard as you think it is:thumbsup:

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Guys thanks for all the advise! grayracer513, they said it did not drop a valve it had something to do with the rod and crank. Rusty92, yes I would love to learn to do all the work myself but I'm disabled and can't do much, but I do go with my Son ( 17yr ) to the track and watch him loving the bike.

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Guys thanks for all the advise! grayracer513, they said it did not drop a valve it had something to do with the rod and crank. Rusty92, yes I would love to learn to do all the work myself but I'm disabled and can't do much, but I do go with my Son ( 17yr ) to the track and watch him loving the bike.

One awesome DAD :)

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Based on what the dealership is saying, they are not confidence inspiring. The dirt in the bottom end from a dirty airfilter is bs. Also, $1,900 sounds kind of step.

But again, they have not yet torn the engine down.

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I got the call yesterday from the Yamaha dealership service manager and he said that the crank froze up and it also done some damage to the cylinder. I asked what would cause the crank to do that and he said that it was probaly from age. He also told me that it will be less than $1900. in order to keep me as a customer. He said it would be around $1700. or less.

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The '03's do occasionally lock the big end, usually because the roller cage fails, and there is never any warning beforehand. So you would ordinarily be looking at a crank assembly, 8 bearings (unless you know how old the 6 for the trans and balancer are), a cylinder, piston, pin, and rings, plus gaskets and misc. parts. That's probably about $900 in parts at retail, perhaps more.

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Thanks Grayracer513. They will be rebuilding the whole engine, Topend and Bottomend for that price. I thought that while they do the bottomend go ahead and do the topend as well, that way it will be like it was a new engine.

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man thats makes me feel like a dick well im sorry to hear that you are im sure that you dont want anyones symphaty but the best of luck to you

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