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sordze25

blown motor

20 posts in this topic

yes it was a bad day today.

I have yet to see the exact damage that's happened to my 2003 wr450. Im to scared to look. but what i can see from the outside is connecting rod protuding out of the front of the cylinder. there is also a crack down the right side of my crank. My question is I am from Edmonton Ab. Where is the best place to order parts from. (cheaper is better than quicker as i am on abit of a budget.) Suspecting by the look of some of the damage i will need a new cyl. , piston, crank assembly, half a crank cover(if there is such a thing, may have to buy whole thing) etc. :applause: also i was wondering if anyone else has had this much damage under normal riding. ( 1800 miles with orginal piston ) use yamalube syn. oil changed after every 2 rides, clean filter ... generally well maintained, or so i thought.

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The Thumpertalk store here seems to be the cheapest, by a long way.

Sorry to hear about your bike, it is extremely rare to see a yamaha grenade its self like the way you describe.

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what was the situation when it tore up? Were you screaming along, pulling a hill, what were you doing? Were there any signs leading up that you may have dismissed, but in hindsight could have helped you. Was it getting difficult to start?

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what was the situation when it tore up? Were you screaming along, pulling a hill, what were you doing? Were there any signs leading up that you may have dismissed, but in hindsight could have helped you. Was it getting difficult to start?

Yeah sorry to hear about it :applause: ,

but good qusetion, was there anything leading up too it that might of caused it?

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spent an hour at the track, then spent an hour in the sand dunes riding pretty hard, then proceded back to the track via highway where i had it full out in 5th for about five seconds when the rear wheel locked up. bike was running great though with no signs of blowing.

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just talked to a mech. who says i should have replaced my piston after so many hours. is this true on a four stroke? i don't race, but i tend to go to the dunes quite abit which is really hard riding.

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I blew my wr426 the exact same way...I never saw it coming, the rod ripped thru the cylinder and case.

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HI,

You should change piston + rings and conrod after 100hrs

Timo Mc

Maybe on a Supermoto (and a bike ridden in the dunes alot) but on a WR ridden offroad :applause: I don't think so....... if everyone did that I would be willing to bet you would see more threads about engine problems due to shade tree top end work.......... Just my .02 cents worth

:D

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The Thumpertalk store here seems to be the cheapest, by a long way.

Sorry to hear about your bike, it is extremely rare to see a yamaha grenade its self like the way you describe.

:applause: Im with this guy. TT is the hook up. Sorry to hear about the implosion. I've been shreddin knobs on the street for almost 10,000 miles now...hope that I have no such luck. :D

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Wow, that sounds way expensive :applause:

Its a racing motor that red lines up around 11,500 rpm's. Mechanical failures can and do happen. You might know what caused it after you tear it down. Usually when a rod bends and breaks through the block, its cause the piston exploded. Could be a valve keeper failed, broken or weak valve spring, or there was a flaw in the quality of one of the parts that metal fatigue gave way to.

But I really dont think im gonna start rebuilding my bike every 2 months with a piston and rod. :D

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CHeck E BAY I recently saw a YZ motor on there. Just look to make sure the seller has good feedback. By the way the 100 hr piston job sounds like a two stroke problem to me! Sorry to hear about your trouble.

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Hey Sordze,

Sorry to hear about the damage.

Keep us up to date on the progress of the rebuild.

I'm from the Edmonton area too so am very interested to learn which dealers in town have been the most/least help to you.

Good luck.

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Maybe on a Supermoto (and a bike ridden in the dunes alot) but on a WR ridden offroad :applause: I don't think so....... if everyone did that I would be willing to bet you would see more threads about engine problems due to shade tree top end work.......... Just my .02 cents worth

:D

Yeah, The piston should last more than that. I rode my '00 Wr for 4 years and thousands of miles and the piston and rings were within specs. I'd suspect a small end rod bearing in something like this, not the piston. My motor did have a slightly scored small end when I took it apart.

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I tend to agree with R Little, possible small end bearing failure. Changing pistons often is for 2T's.

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Small end bearing was the only part of my engine that had wear to it, when i cracked it open this spring..

I also changed the piston, but the original piston was still in spec.. Allthough mine wasn burned on one side after the oildrain got loose...

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Do you know about how many hours you had on the bike? I had 300 hours on my 03 before I changed the piston and rings. I would look for another engine or bike as the cost to fix what you have is spendy!

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No i dont know this :applause: I bought it used, and without any hour meter or odometer that tells the total.. But i really dont think it had been doing alot of hours, but i suspect that there has been used way to thick oil at winter time..

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finally got around to pulling motor apart. when i pulled the head apart i noticed the bolts holding intake cam were loose. upon further inspection intake cam ground its way down causing valves to possibly interfere with piston. Looks to be even worse than i thought. Need new head now as well as cam and valves, cyl, crank case piston etc. Anybody out there selling a complete motor. Had about 250 hours on mine. Guess i should have opened it up a long time ago.

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Sounds like a complete motor would be the best investment, but dont forget that the new motor youre buying might be due for some rebuilding too!

250hr was a little early i think..

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